Before you read the  forecast   BELOW  Please    click on     THIS   LINK .   There are some  points  I need to make   before you read the forecast below   

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.AS   OF  1511    EDT   3 MAY    2012 ……    If   you are running a  weather   sensitive Business…   such as a   Propane or Energy…  Mountains resorts… Marinas …. landscaping….  or  construction  and    you need    DETAILED    two and three   week forecasts  you  really should   try  VA   BUSINESS  Weather  Newsletter    ( The   VA Business  Weather Newsletter   is a paid  subscription    service.   If you are interested    send me an   Email at  wxrisk@comcast.net  or   at   facebook.com/ wxrisk  )

 CLICK  ON  THE  MAPS   FOR   FULL  SIZE 

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THIS  COMING   WEEKEND      MAY   4-5-6
 

the  MAIN  feature this  weekend will be the  cold   front  dropping North to south through the area.  FRIDAY MAY 4  will be the  most    ” unsettled” of the  3 days    with  storms   likely   over much of central and     eastern Virginia and eastern MD   Friday  4-8 PM.   There    COULD  be a  SEVER E THUNDERSTORM   WATCH  issuesd  by   NWS/ SPC.   SUNDAY  MAY 6  will be  the    best of the 3 days with NO rain anywhere and   dry  / low   Humidity
FRIDAY   MAY  4	SATURDAY   MAY  5	SUNDAY  MAY 6

HPC official   Day  1-5  rainfall total forecast is pretty impressive with regard to the event coming up the East Coast late this weekend early next week.  They show a large areas of 1 to 5 inch rains which is what I was talking about earlier in the week.

This is a pretty good indication that the forecast of holding  without a lot a changes but there are still some issues of uncertainty here  which  mainly  centered around

1 the track of the   surface  Low   up the   coast
2 and the  the  Upper  Low  and Vort max   in the base of the trough Sunday Morning.

It is essentially these two features   of this event which will determine  the potential for any sort of significant severe weather outbreak    in NC   VA  MD  DE    eastern PA    and NJ/ NYC.

In my first posting on this event over on the FACEBOOK/ wxrisk.com  page my initial belief and concern is to play up the severe weather threat  in addition to the idea of heavy rain especially for the area from    RDU to   PHL.     The weather models on Monday–   see  these two images — clearly showed that the phasing between the Upper Low over the Gulf coast and the    Midwest trough   ” digging :” into  the  SE states would grab the  surface LOW  and  pull  it  NORTH … NOT  Northeast.  This would allow the warm sector of the system to cover most of the mid Atlantic states with the surface LOW going up the spine of the Appalachians.  And as you can see the European model and Monday had the main   Vort max tracking very close to the  surface Low  and right over  RDU RIC   DCA   corridor.

12Z MONDAY AFTERNOON EUROPEAN MODEL valid 4/22

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12Z MONDAY AFTERNOON EURO MODEL valid 4/23

However since then    some of the models  have been  wavering with regard to the track of the  LOW.  This is such a significant coastal Low that some of weather hobbyists/ weenies maybe lamenting the fact that this is not occurring on February 23rd-24th because is a waste of a perfectly good coastal storm.  However I need to point out that even  if this system had occurred in late January or February it would be primarily a rain event for most of the coastal areas of the middle Atlantic  and the New England  nregions.  The entire  synoptic ( large scale atmosphere features)  is   completely wrong for anything resembling a significant East Coast winter storm for the coastal areas.

That being said…  IF…IF…   this coastal Low  were track closer to the coast… it would pull the  stalled front  from the Appalachian Mts towards the eastern  coastal areas of  NC  VA  MD .  The low level winds will become North  once the Low  reached these  eastern areas …   whch means    there  would only  be widespread heavy rains with maybe a rumble or  two of thunder ….but no significant severe weather event.  You simply do not get  ANY   kind of severe weather on the  East coast  with a coastal Low on   or  just  off the coast  with  strong  Northeast winds.  The key word here is of course significant.  And this  rule  …such as it  is… does  NOT apply  to   AL   GA SC  for  southeast   NC.

This image shows the European model from early this morning and as you can see the model clearly has a complete phase between the southern closed  Upper Low and the energy coming into the Ohio Valley from the great lakes.  They had perfect phasing of the two jet streams allows the surface low to be captured  under the   large  deep closed Upper Low  and   the Low gets  pulled North into central and Western   portions of Virginia  then into Western Pennsylvania.  In fact according to the oz  WED  European… the Low   stalls Monday morning over western of Central Pennsylvania–  New York City and Boston  would bec seeing  warm temperatures and rain   while cold air is over  WVA    western MD and most of VA.

This inland solution was supported by the 0Z  EURO ENSEMBLE    and 0z GFS .

but the 6z GFS    shifted East again taking the SE  LOW  to the NC  – VA  coastal areas…  And thus removing the threat of any sort of significant widespread severe weather for  mich of  western  & central NC and most of VA.

Unfortunately the GFS flip flop again hre at midday   with the 12z  WED    run shifting the track back to the west once more.  As you can see from this link the model now shows that the two streams to phase .  This means the southern Upper Low and  its surface Low   gets   “captured”  and pulled northward up the spine of the Appalachians…  which means that most of North Carolina Virginia and Maryland stays in the warm sector as the heart of the energy comes over these areas on Sunday.  As I said before this sort of scenario    / tracks   sets the stage for significant severe weather threat for some areas.

Complicating this even further is the new one of the European which has just come out — the 12z   WED  run.  This run of the  ECMWF  Has shifted back to the east a little bit which reduces the severe weather threat.  According to the new   run  of the European..  The phasing between the two streams takes longer to develop which forces the southeastern Low at the surface to track further to the east.

When the new 12z  European ensmbles come out it will be interesting to see if ensemble   MEAN  is supportive of the operational European or whether not it holds the consistent trend of the system tracking inland .

Of course is possible that  would they end of saying a compromise solution.  That is to say the southeast surface low tracks up into Eastern North Carolina and then makes a slow look to the Eastern VA   or  southern MD coast.  This would still placed the potential for some severe weather into Eastern Virginia but the western half of the state   as well as    WVA would see mostly just heavy steady rain.

Here is the  12z  UKMET  from  todays ‘s 12z  run… again the Low tracks  Due North  because the UKMET  says   the   2  features   Phase and  th   Low gets Pulled Due  North   into  VA  then PA

It is not out of   the question that on Monday …. IF … this system is actually has deep and as powerful as some of the models are showing…  that the rain could go over snow with the mountains of north central Pennsylvania  into central and Northeast New York State.

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2100 EDT  17 APRIL  2012 … STAR DATE   201204.17

There is increasing potential for a significant or major severe weather outbreak for much of the southeast and lower Middle Atlantic states this coming weekend. (GA SC NC VA MD eastern TN and WVA) .  Inn addition there will be   widespread  1 to 3 inch rains from  GA  to Maine   4/22 to 4/24

So far this SPRING 2012 we have been pretty lucky on the East Coast but does not look like that Luck is going to last.

Starting at the end of this week the jet stream over the eastern portion of North America is going to undergo a major amplification.    A deep trough in the jet stream is going to form over the eastern Pacific Ocean on Thursday and Friday. This in turn… will force a large  ridge to form over the West Coast and the Rockies…    which   in turn will force large deep trough to form over the East coast this coming weekend.
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At the surface this will appear as the cold front which will move through the Midwest on Friday and head towards East Coast. However because of this deep trough that will building over the East Coast…the cold front will come to a screeching halt along the East Coast running on a line from Atlanta to Albany NY.
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Low pressure is going to form over AL and GA on Saturday and track up the Appalachian Mts along the stalled cold front and head into eastern PA eastern NY State and New England by Monday.  In some ways this Low track will be similar to what we might see during the wintertime with regard to East Coast winter storm. But there are some important differences.
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FIRST… ahead of this cold front is going to turn very warm again up and down the East Coast.
SECOND… HIGH pressure off the East Coast will be sending in strong southerly winds which will increase the low level moisture from SC to Maine ahead of the cold front.
THIRD.. The pattern that sets up in the jet stream at the upper levels of the atmosphere will become very ominous looking for the East Coast and especially for GA to MD. The Jetstream over the East Coast will take on a particular tilt or alignment in the atmosphere which meteorologists call a negative tilt -- this is when the trough axis is aligned in a NW to SE direction.
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Thus when the surface area of LOW pressure forms over GA on Saturday it will rapidly intensified as it tracks over Raliegh and central NC and into central VA/ metro Richmond area on Sunday. Because of the temperature contrast west of the front vs. east of the front… the low level southeasterly winds… the upper level south winds that will become Easterly as the Low tracks through NC and VA the potential exists for significant severe weather outbreak from Georgia into New England.
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These two LINKS can show you the threat nicely
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12Z MONDAY AFTERNOON EUROPEAN MODEL valid 4/22

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12Z MONDAY AFTERNOON EURO MODEL valid 4/23

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The thunderstorms will not only be significant rain producers but the potential exists for   Tornadic  thunderstorms as well as large HAIL.    Over the next two days I will be issuing statements on this as we get closer and closer to the event.   Most areas up and down the East Coast will see anywhere from 1 to 4 inches of rain BUT … over the mountains blue rudge and the Shenandoah Valley as well as Western NC western MD and central and northeastern PA rainfall amounts could be significantly higher.
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Here is the approximate sequence of events for this weekend starting on Friday.
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FRIDAY 4/20. Everybody looks fine. The looks warm and sunny the coal fund will be sweeping through the delta and the Ohio Valley. There’ wil be increasing showers and thunderstorms developing Friday night into Saturday morning over AL GA eastern TN.

SATURDAY 4/21 storms/ rain over GA SC eastern TN and western NC but it will stay dry and even sunny over eastern half NC most fo VA MD DE eastern PA.

SAT NIGHT: Heavy storms /rains move north in western VA by 8pm into western MD central PA… and into all of eastern NC VA central MD by 2am Sunday and into MD eastern PA and NJ as well as NYC

SUNDAY morning the Upper and surface Low right travel right over Raliegh and through central VA / Richmond. SEVERE WX THREAT could be HIGH for all of northern half NC – VA-MD with heavy rain. More heavy rains all for central and eastern PA NJ DE eastern NY Moderate rains into New England … by 2pm LOW is right over Richmond VA… not good

SUNDAY 7PM… the surface LOW begins to Weaken as it moves into eastern MD and towards Philly … worst is over for NC MD VA ..still some rain over nw VA and western MD and western PA… heavy rains in the NE ;

MONDAY 7AM Low is over Philly Squall line of severe storms driving thru NJ NYC se NY Long island into CT

After record shattering warm March 2012 the pattern has shifted into something that winter lovers would love to see during the cold season months. APRIL 2012 is not going to be any where NEAR as warm as February and March was.     Late last week I issued a statement over on the Facebook page about the possibility of significant coastal storm for some portion of the East Coast during the Easter weekend.    That possibility still there but the data appears to be turning away from the big solution into smaller event

IMAGE #1 is a depiction of the current hemispheric pattern and I am using the initialization of the European on this Monday afternoon April 2. We have a very clearly defined  and easily discernible 4 wave pattern which has set up across the northern hemisphere with four large distinct Vortexes across northern hemisphere. I have highlighted these features  to  assist   in pointing pointing out   these  4  powerful large vortexes at 500 MB.:
Eastern Siberia… the Gulf Alaska ….southeastern Canada …and Scandinavia in Europe.

This is a very different pattern from what the atmosphere has been depicting over the past 4 or 5 months. More importantly…   a 4 wave pattern is very stable and is likely to stay in place for prolonged period of time. This is especially true with the NAO moving into the negative phase and possibly the AO ( arctic oscillation ) moving into the negative phase as well.

IMAGE #2 is the 12z Monday April European model valid for 72 hours ( 12z APRIL 5).    Again there are several noticeable features here.    First we can clearly see that the north Atlantic “THUMB RIDGE ” has now extended all the way into southern Greenland.    Parenthetically this has always been a point of contention with some uninformed and meteorologists and weather hobbyists: they seem to be fixated on the fact that every single Ridge n the north Atlantic is an automatic -NAO. A few weeks ago I got into a debate with some weenie on the FB page who tried to argue that having a strong ridge in the north Atlantic at 500 MB was a -NAO … and the fact that there was a huge closed deep 500 mb Low centered over Greenland did NOT count. Oh well.

But I digress. We can see a very important closed upper Low moving through the central Plains and the Lower Mississippi Valley.   This feature is part of the trough which is now over the Rockies and it is going to separate itself from the main flow on Tuesday and Wednesday.   However the number of large and powerful systems coming in across the northern Pacific into the West Coast North America shows no signs of letting up.   I have highlighted  two  important troughs in the Jet streams moving across the northern Pacific towards the West Coast.     In response to the deep and persistent   trough   over the West Coast the atmosphere is countering this feature by developing a strong Ridge over the eastern Rockies and western Plains which extends all way up into South Central Canada. This Ridge is VERY important…. because it does a number of important things…

FIRST …. these huge trough coming into the West Coast are being diverted into Western Canada and the northern Rockies which means that the upper Plains … the Upper Miss valley and south central Canada — Manitoba and eastern Saskatchewan areas  are  not getting the needed  moisture that those area needs   we move   into the heart of the Spring season.     SECOND…  the combination of the huge Ridge over the Rockies and Plains … with the -NAO over Greenland…. strongly favors a persistent and possibly a deep trough over the eastern Conus    (probably over the East Coast ).    This in turn favors below normal temperatures EAST of  the Mississippi River as long as is pattern holds. This sort of pattern is strongly supported by the Current MJO.

IMAGE #3 shows the latest European MJO forecast plots the European ensemble MJO forecast and the Ukmet forecast Plots.   As you can see over the next 7 to 10 days the data shows the current MJO will pick up in intensity then move through phase 8 and into Phase 1.   During the month of April the MJO in Phase 8 and 1 strongly supports a persistent trough over the East coast of the CONUS.

IMAGE #4 shows the 12z European model valid for 96 hours.    Note that the Upper Low that was over KS and KS has tracked ESE or SE towards the se US coast.   This is significantly different from what the model data was showing late last week;    The European model was taking this Upper Low due east to VA-NC. and  this sort of track WOULD  have  supported a significant phasing between the Upper Low in NC / VA and  the Huge Upper Low over southeast Canada..   and hence the Coastal Low.     However if the  APRIL 2 European models are correct …  the system dives of southeast  and  the potential for a significant coastal Low is much reduced. The track of the upper Low to the SE tells us that the overall   pattern  along the East Coast is not favorable for phasing but instead is favorable for suppression.     The model  produces    a coastal low off the SC- GA  Coast which would impact places such as the Masters golf tournament in Augusta.    But the coastal Low in this set up would move ENE out to sea.     April 6 and 7 would be cold — relatively speaking –with large HIGH pressure covering most of the East Coast.

But in addition …we also have that next strong system coming out of the west coast and tracking northeast into the northern Rockies ( see the “X” spot on the MAP in Image #4).   This piece of energy ( a ” short wave”)   is about to develop a   “negative tilt  ”    and this allows for the surface  Low to develop rapidly  and pull  in cold air from southwest Canada …and producing snow over Eastern MT     and  possibly the western Dakotas  on APRIL 6-7.

IMAGE #5  … shows the 12z European Model valid at 120 hrs .   The intensifying LOW  over the western Dakotas can clearly be seen — which I have highlighted in a white circle.   The Sunday GFS model runs were also quite bullish on this feature and developed a significant late season snowstorm for the western Dakotas into southern and central Manitoba APRIL 6-7.    Meanwhile over the eastern CONUS… we can see the Low way off the southeast coast and heading out to sea .

IMAGE #6 shows the day 8   ( 192 hr)   12z April 2 European model. That piece of energy which may or may not bring a snowstorm too the western Dakotas  and Manitoba …   ends up going  over the top of that huge Ridge in the Rockies and Plains …then drops southeast  into the deep trough over the East Coast.    At the surface the amplification of this trough causes a large cold HIGH to form and come south over ND… and strong surface cold front driving rapidly through the central Plains …the lower Midwest ….and into the Middle Atlantic states.    The model even develops a wave of Low pressure on the front across Central Virginia.    As you can see the dark purples and blues over south central Canada -which represents very cold temperatures for early April — is being driven southward on strong northerly winds.

IMAGE # 7 show the day 10 European with a very impressive colder outbreak which given the fact that it’s mid April… could really be called an ” arctic” outbreak.      If this map turns out to be correct we would see a hard frost and freeze across all of the Midwest east the Mississippi River and there would be significant damage to many of the vineyards across North Carolina Virginia West Virginia Maryland Pennsylvania and Western New York.

IMAGE #8 shows the 6-10 day 850 temperature anomalies…. Now we need to check the operational European because as impressive as it is the European ensemble might show something significantly different.

IMAGE # 9 is a comparison of the European Ensemble vs the operational.     In the general maps are somewhat similar but as you can see the trough over the eastern CONUS is much less amplified and therefore would not pose a threat for saying significant cold over the East Coast APRIL 10-11-12.

What happens after APRIL 11-12…. is somewhat uncertain.   If you notice the MJO forecast plots back in image #3… the Model forecast plots clearly shows the impulse collapsing rapidly in phase 1 and moving into the neutral or circle of death zone in the middle of the chart/ diagram.   This sort of development would mean that more uncertainty and shift to a pattern of persistence.

 some of you may to  have to  COPY  and patse this link 

http://1664596.sites.myregisteredsite.com/seasonalforcst/SPRING2012/SPRING2012public.htm

Well my post winter break is over so   it is  time to start posting  and  doing weather analysis again.  For those of you that are new to the website as a general rule after the Winter ….I usually take a week or two off just to recharge my batteries.  In addition I  have   to switch   my  focus  on  to the  SPRING forecast for my grain clients.  The SPRING 2012  forecast has already been available for  my   grain and agricultural clients for few weeks …  But there are some contractual obligations about releasing the SPRING  forecast on the web site for the general public  too  early.  However I can announce that the spring forecast will be on the website Friday morning MARCH 16.

This remarkable stretch of exceptional warmth which I predicted  on the  FACEBOOK Page  back on March  1 st  2nd and 3rd…  shows no signs of letting up and  it is quite remarkable.  Of course  the immediate concern  seems to be  that since  SPRING 2012   has jumped off to an early age    WARM   start     (which could be argued that these temperatures relative to normal are downright  “HOT”) …  that   it somehow implies   or increases the chances   that the SUMMER 2012  is going to be a hot and dry   for much of the central and eastern CONUS       ( CONUS  =  contiguous 48 lower   states).   While that concern is only natural the fact is that  IF…  we are going to move into   EL NINO    by MAY 2012  …  rhen the odds would clearly not favor a hot and dry summer over most of the central and eastern  CONUS.

If we take a look at why the pattern has turned  so very warm…  the actual  causes  become  well   kind of obvious.  Once again we have a large deep vortex    (feature  #1 ) centered as it has been all winter long over Alaska and the Bering sea!  That feature still has not yet moved.!!  The persistence of this thing is really remarkable and continues to dominate the entire pattern over the western hemisphere the planet.
And because we have that deep   500 Low or   vortex  over the Bering sea and western Alaska…  this forces the jet stream coming across the northern Pacific south of the vortex to get compacted … SQUASHED!!!   ( feature #2) .  Because of these   enhanced  velocties   in the Pacific jet …. it continues to  crash  these major   weather systems  and    short waves   (upepr air energy)  into Western North America  and carving out deep troughs into British Columbia the Pacific Northwest and the California Coast .    In order to counter this influence of the deep trough on the West Coast the atmosphere responds by developing a  RIDGE   in the Jet stream downstream  . FEATURE  #3.
In addition we still have a very east positive NAO …  Along with a very strong    RIDGE   over the  Azores in the northeast North Atlantic Ocean.  This Ridge  extends into the United Kingdom and all of western   Europe.
Over the next several days a major surge in the Pacific jet is going to carve out a huge trough over the west coast of North America.  And of course the atmosphere has to counter that somehow which in this case means the Ridge  over the  central and   eastern US  is going to get amplified driving north into the great lakes and even into Southern Quebec Canada    starting this weekend and continuing through all of next week.

Now if you are located  underneath this RiDGE or  to the east…  It means more amazingly nice weather with lots of sunshine very little rain and warm temperatures.  It  is quite possible this warm dry pattern will last over all of the central and eastern half of the country until the end of the month!  On the other hand  the   deep  trough over the   West coast  and the  Great Basin means more much below normal temperatures times of heavy rain and really miserable conditions for these areas.
Eventually as the deep trough pushes east across   the Rockies and into the Plains significant showers and thunderstorms will develop along the surface cold front.  The Gulf of Mexico will be open for business.   Yesterday — MARCH   14…. the European model was developing a closed   cutoff    DEEP   500 Low  over  the Lower  and  central  Plains    in the   8 to 10 day time frame.  Initially I viewed this development with some skepticism

but after seeing the Thursday morning in midday data it’s pretty obvious that the models are really going gangbusters with this idea of a   closed cutoff    deep 500 Low getting trapped over the eastern portions of the lower Plains …the Delta and the Tennessee Valley.

The development of this system is important because  WHERE   the closed cut off  500 Low   forms will determine what happens to the jet stream over Eastern Canada and the Northeast US.    Yesterday the Wednesday afternoon European model was developing  new   closed  500 Low over  New foundland Canada.  The model  was showing   that the interaction  of this  Low  over Southeast Canada and the    Upper Low  stalled  over the  central Mississippi Valley  would cause   a large cool  HIGH to form over southeastern Canada  — Quebec and eastern Ontario.   This in turn were dry the    BACK DOOR  cold front into all the Northeast us…  as far south as Virginia North Carolina and as far west as Michigan and Ohio.  Keep in mind that the ocean water  temperatures are still frightfully cold so  the any time in the northeast  US    you get an NE   or  EAST  wind   in March and  April…   temperatures will   tumble very quickly especially  along coastal areas.
That being said it is not at all certain that  there will  be  a backdoor cold front.  It’s possible that the models may be over developing this system over southeastern Canada…  so  if that feature turned out to be a lot weaker…  then we end up getting no large cold HIGH forming over Eastern Canada and hence no back were cold front.

As we look towards the end of the month– say the last week of  MARCH  2012  and possibly into early April  2012…  the model data continues to show very strong Pacific jet sending in more energy down from the gulf Alaska into the west coast of Canada and  the US.  Clearly if this happens again that we will  see another strong large   Ridge over the  Midwest and Northeast   happening again..  Indeed the GFS     CMC  and the  ECMWF   11-15  day  all show this happening during the last week of March and  the 1st week of  APRIL.

Exactly one week ago  — FEB 19– eastern Kentucky the southern half a West Virginia and Virginia experienced a significant snowstorm.  I have had a week now to think about   this event and to compile all of my forecasts… statements and present a thorough review.  Thus this  web page entry.

In addition I will explain why I argued so strongly that this was going to be a KY  WVA VA  snowstorm and that the system had little chance of turning up the coast into the big cities of the northeast.  As  we go  through this analysis  I will stress  several key points.

1.  The  pattern  strongly favored  this Low tracking ENE  off the NC coast and not coming  up the coast.   Unfortunately   many Meteorologists  and weather Hobbyists  along the  East coast  were   ignorant   of this and blindly  clung to the   old  saying
   ” the north trend “. 
2.  The GFS Model  performance sucked moose. The Model performance was appallingly  bad   in the period from  day 10/ FEB 10  to  Day2/FEB 17 with frequent  wild swings  from  solution to solution.  
3.  The close adherence of this seriously  flawed Model by   weather  hobbyist and professional meteorologist caused unnecessary Hedging and   uncertainty in the forecast.

The first statement was issued by me based upon the Day 10 12z European model February 10 run….  which showed a significant Low pressure area along the just off the southeast coast of North Carolina.  It turns out that the day 10 European model from FEB 10 was amazingly accurate and as close to a direct hit with respect to the actual surface   on February 19   for a  ten day forecast as  you have.  Of course the   FEB 10 European model   was off by one day but still  the  day 10 European  model  depiction  was pretty darn good.

FRIDAY  FEB 10  235 PM  I  posted    this:

* ALERT DAY 10 EUROPEAN MODEL HAS MAJOR EAST COAST SNOWSTORM … even for most of NC and all of MD and VA on  FEB 20

Of course several  times this winter we seen false alerts from weather models especially  at Day 8  Day 10  and Day 12.  However in this  case something was different with respect to the large scale or synoptic pattern.  The PRIMARY    reason WHY I believe this event had a better chance to become a reality  and a significant  event  … even at Day 10…  was the collapse  that was  forecasted by all the models of the super intense and large Polar  Vortex   (PV) over Eastern Canada.

I have said this many times before and I am sure I will say again.  The overwhelming amount of data shows that having a large powerful intense PV over eastern Canada— over Hudson’s Bay or  central or Northern Quebec / or Labrador–is an extremely negative or Hostile  synoptic  feature to development of major East Coast Winter storms.  Having the PV below 500 dm  in that geographical position is a  manifestation of the  + AO pattern.  That being  said … if  one  looks at the 500 mb maps  in  January and  early February you would  have seen a   large intense   PV  situated consistently over northern Hudson’s bay or Northern Quebec  or Baffin island.  Sometimes this feature has been as low as  474  dm and has been so large that it has  6  or  8     lines — height lines –around it.   That represents a lot of wind and  energy and becomes extremely hard to get the Polar Jet  (PJ)  to dive south and  merge or   “phase” with  the subtropical jet  (STJ)  over the Eastern CONUS.  And without the phasing…  you don’t get big winter East Coast storms.

In addition on the 10th I argued that  another key aspect to this  POSSIBLE event  happening was the cold front and significant Low pressure area tracking through the Great Lakes and February 17.  In order for this possible winter storm scenario to develop  the Great Lakes   Low had to move into southeastern Canada and become a  50 /50 Low.  This in turn would force the cold air south  into the Northeast   US and prevent the next system and tracking up into the Ohio Valley.

The    12z  FEB 10 european  had some partial support the next morning   from the 6z   GFS but  the model  truncation  after day 8/192 hour  clearly  caused the  flawed  GFS Model  to “lose ” the southern  system (the short  wave)  at the 500 MB.

The  12z  FEB 11  operational  European  model had the  southeast Low  but it was further south. The 12z  euro  ensemble  had the Low 200 miles further North  and this trend continued  with the 0z  FEB 12  run of the Operational European… and I posted   this  on the Facebook  (FB) page at 0155 hrs  12FEB

*** ALERT *** ABOUT FEB 19-20 THREAT ****  
The  NEW 0Z — early Sunday AM –   run of   the  ECMWF ( the european) shows a  CLASSIC VA -NC -MD SNOWSTORM  … but only  IF one looks at UPPER AIR maps .   But the surface map does NOT look all that good.   At 500mb  on day 8 – 7PM SAT FEB 18 the 0z euro has closed 500 Low centered over central ILL -IND…. the surface Low for  some reason is waaaay to the south which makes NO sense . The Model has the surface Low on the SC coast which is a tad  further North than the 12z Saturday run. BY the Morning of FEB 19 the closed 500 low is right over southern VA … and there is some snow falling  over central and eastern VA…. but again the Surface Low is waaaaaaay to the east which makes NO sense.

On the   other hand   the 0z  GFS   took the Low  into the Great Lakes  and  developed a   strong  SE  ridge.

However the 12z GFS  FEB 12  run  showed  a Major change or     “flip flop”  in that  the Model  took the Low  from MI  to the  GA coast and showed the   southern energy  — the short  wave–  weakening   rapidly as  it  propagated  east along  the  Gulf coast.

The 12z  Euro  run on 12 FEB  remained   very consistent. The model  detected   2   pieces of energy — 2  short waves -  over  TX and KS –  that   merged  or  Phased into  a  stronger  southern short wave  that developed a  Negative   tilt.  This in turn argued that the  surface Low  should be closer to the coast  than what the  Model  was depicting with its surface map for  FEB 19.

A SIGNIFICANT  development  occurred on the  0z  FEB 13 Model runs when the CMC or Canadian  model which had been showing no  development of the southern shortwave for the last several model runs…  turned it towards the European solution by developing a significant area of Low pressure along the Southeast US coast that bought significant snow into the southern half of Virginia.  Such a development of course began speculation about the new north trend as it almost always does but as we will see in this case that was not to be for number of different reasons.   On MONDAY    FEB 13    at 0121  hrs  I posted this …

‎0Z CMC MAPS FOR ALL TO SEE.. SIGNIFICANT SNOWFALL for southern VA standards NOT for say NYC or PHL or BOS standards into southern 25% of VA. This is BIG leap in what THIS Model was showing when compared to earlier runs… 

The trend continued with the 0z   13 FEB  run of the European model which showed it even bigger and more developed southeast US  coastal Low   tracking the low over or close to Cape  Hatteras. However the model began to experience problems with the northern and the precipitation shield.

Later that day  the  the operational run   of the 12z FEB  13 run of    GFS   Model came out with a dramatically different solution which caused a significant reaction with some of the more poorly informed meteorologists.  The GFS showed a major jump northward in its position of the southeast low so that it bought significant snow into the big cities of the northeast. Upon seeing this run I posted the following on the FB  page

* COMMENTS ON 12Z MONDAY 13 FEB  GFS run — REGARDING FEB 19-20 ** Ignore this run of the GFS ..it has huge error in it that Just forces the model to go off the reservation into idiot land.

This was followed by the assessment from  HPC/ NWS the declared the  12z 13 FEB  operational GFS to be seriously flawed bcause of corrupted data the getting into the model .

Of course that drew a very strong reaction from several sources both from whether hobbyists and from professional meteorologist who should have known better.  The statement from HPC was pretty strong and I don’t see how anybody could have possibly ignored their argument.

Leading the charge that the GFS solution was correct after all was of course  Joe Bastardi.  He made the argument that this  dropping  the operational GFS and its north trend was the same sort of mistake that  HPC made   with regard to the East Coast historic snowstorm   25-26  DEC  2010.  If you recall the  particulars  of that event … it brought 10 to 20 inches of snow from   eastern NC through  Norfolk across the lower Maryland eastern shore into the big cities of Philadelphia New Jersey and New York City and then into Southern New England.

Bastardi argument was of course absurd and had  little basis in reality but he counts on weather  hobbyists  not having a firm grasp of what the actual facts were in a particular situation.  The truth is that in the days leading up to the  25-26 DEC  2010 historic snowstorm   ALL of the models had   shown the same solution for several days.  This was not a case of one model showing ABC  while another model showed  XYZ   and another  showed  HIJ.  But more importantly on the day before the actual   25 DEC 2010   Major  East Coast Snowstorm …   all the model data   — the European …  the Canadian ….the British  AND  the GFS  ….and ALL of  the short range models for that matter as well — all took the potential coastal snowstorm   way out to sea .  It was  NOT  the case of a   ONE  model coming up with a bizarre solution and being dropped by   HPC.

In addition his analogy also fails because just as all the models both the global and shore range models  suddenly took the coastal storm out to sea on  the December 24 model  runs…  that Night  on Christmas Eve …ALL  of the models  suddenly  reversed course and bought and be major snowstorm for the immediate  coastal areas from Virginia to Boston.

Never let facts get in the way of good   Bullshit.

Fortunately even while the debate regarding the  obviously flawed  12z GFS  Model was raging on midday on the 13th of February   the 12z  Ukmet  came out and showed a  Major   se US Low tracking over Cape Hatteras and moving out to sea bringing a significant snowstorm to much of western NC …VA … and   southern Maryland.

1239PM  FEB 13  I  made this  post on  the FB page

**ALERT *** ALERT *** 12Z UKMET GOES BOOM.. shows major east coast snowstorm FEB 19…. for entire Middle Atlantic even VA and MD into NYC LI and southern  CT.

This was followed shortly by the  12z run  of the European model which developed the southeast low a little deeper and took it further to the north ride along the South Carolina North Carolina coastal areas with the track running from Charleston to Wilmington to Cape Hatteras.   This cause me to make the following post  on the FB page.

FEB 13  132  PM     ‎*** ALERT *** ALERT ***ALERT …. this is No drill … 12Z EURO brings  in MUCH stronger  SE US Low   with HEAVY SNOW to all of central and eastern VA –over 6 inchesand much of Northern NC …. POSSIBLE ACCUMULATING SNOW late on the 18th into the 19th… WOOF WOOF BARK WOOF…  

At this Point I tried to make the argument that  the overall pattern clearly did not support a north trend and that the system was not a threat for the big cities the northeast.  Despite the strongly worded statement  from HPC and    the  fact that  the   12z  European Canadian and British models all strongly disagreed with the flawed  12z 13 FEB  GFS   run…  there continue to be a lot of desperate hope   and  the strongly worded assertions that the  12z GFS  was  somehow … that HPC   was wrong ..  had to be at least take into consideration .

However there  was  another way to of solve this dilemma as to which model solution was valid and  which one was not.  That would be to look at the historical analogs and finding similar events as well as using your brain to understand the potential scenarios that a forecast of may consider.

There are specific reasons  or    mechanisms   in the atmosphere  that  determine WHY   Low pressure areas in the winter months that  form in the Gulf     will    turn up the coast  and why some do Lows  are  forced to turn out to sea near or to the south of Cape Hatteras.  This is a science and it is not supposed to  be based on whimsical  Nonsense.    These 3   particular instances or analogs of significant snowstorms   for the lower Middle Atlantic region highlight the reasons and the mechanisms as to WHY Low pressure   along the southeast   US coast might NOT come up the coast.

However if you are unfamiliar with these events and you do not understand the significance of the players on the field especially at   500 MB then you would mis-read the Models and end at making a bad forecast period

  3  CLASSIC  LOWER MIDDLE  ATLANTIC — NC    VA  southern MD   –  SNOWSTORMS OF THE PAST.

case #1  30 JAN 1995…

This first event from 30 JAN 1995… is a very close match to the event of February 19, 2012.  This first image shows the upper air map on the 30 for January, 1995.  As you can see   there is an ULL — Upper Level Low — over the Tennessee Valley in a manner that was very similar to the event of  19 FEB 2012.  But in addition there was a  strong   PV – polar vortex-  located over Eastern Canada.  The PV in the Middle of JAN 1995 was a very intense large PV…  in a manner of very similar to what we saw in the beginning of February  2012.

The SURFACE Map shows   the   se US Low tracking along with just off the Southeast U.S. Coast very close to Cape Hatteras.  These
precipitation maps from   29-30 JAN  1995… and    30-31  JAN   1995 showed that significant   snow  did fall over much of Eastern Kentucky the southern portions  of West Virginia and much of southwestern and Central Virginia.  Even more significant is that in this situation just like in  19 FEB 2012……   the   heaviest snows   fell over  sw VA  and the  southern  Piedmont.

Notice here that he northern jet stream does  NOT  drop or phase into the southern jet stream.  Keep in mind that it is the phasing of the two jet streams between the Mississippi River and the East Coast  which is what develops the coastal Low.   If the two streams do not phase there is no MECHANISM for the   southern short  wave or Low  to come up the coast.

 CASE  #2     2-3 JAN  2002… 

This is also a very close match to the situation  of   19 FEB 2012….  Because the winter of   2001-02 has been very similar in terms of
the overall temperatures and lack of  snow  over the eastern half of  the  CONUS….  And because the winter of   2001-02  was forecasted   to be a fairly cold and stormy winter  over the eastern  CONUS  just like  2011-12.

Here is the SURFACE MAP  from  2 JAN 2002 and it seems to be a near ideal setup for  significant snowstorm into the big cities of the northeast US.

As you can see from these upper air maps JAN  1-2-3 , 2002…  there is a large and very pronounced ULL that  was centered over Iowa and Missouri on January 1.  This feature dropped into the Deep South and then rotated off the Southeast U.S. Coast by January 3.  Note again that there   was  a very deep and very intense    PV — Polar Vortex –  at  480 dm or lower located over Quebec Canada.   Also … note the very strong Pacific trough crashing into the West Coast JAN 1-2, 2002…  which again bears a striking resemblance to the  500 MB     FEB 17-19, 2012.   The analog here is striking we close to what we saw last weekend over  TN KY  NV   and VA.

Notice here that  AGAIN the northern jet stream does NOT  drop or phase into the southern jet stream.  Keep in mind that it is the phasing of the two jet streams between the Mississippi River and the East Coast which is what develops the coastal Low.  If the two
streams do not phase there is no MECHANISM for the   southern short  wave or Low  to come up the coast.

Its Just that   simple.

And by the way …there was  widespread speculation and forecast hoopla that this   Low on the se  US Coast 2 JAN 2002  was also going to turn up the coast.     And finally here is the snowfall accumulation map. In this instance   the best snows were NOT over  sw VA and the
southern Piedmont but over central and southeastern Virginia.  However the principle and the upper maps remain quite relevant and analogous  to  19 FEB 2012.

CASE # 3…   25-27 MARCH   1971…

Again the surface maps appeared to be quite favorable for significant East  Coast snowstorm.  There  is a large arctic HIGH centered over the Great Lakes covering all of the eastern CONUS and a stationary front over Florida and the gulf coast into Southern Texas with significant precipitation developing on the front.  However by 17 March 1971 the significant surface low pressure area moves off the North Carolina Coast and out to sea by passing the big cities of the Northeast.    WHY did this Low  also  ”miss”   the big cities of the  NE and why    heavy snow ONLY  fall over   eastern KY southern  WVA   northern NC and   the southern half of Virginia?

The 500 MB maps clearly show what happened.  In this case we have a very nice   50/50 Low centered over Newfoundland  Canada and this feature is a strong signal for potentially East Coast snowstorm .  We also have a very pronounced   -NAO as well .   And the PV is not very strong and is displaced over North Central Canada.   On 25 MARCH 1971 –  the 1st map– we see a   Upper Low Located over   KS   and the  PJ –polar Jet – is  located along or just to the north of the was Canada border and drops into New England…  while the Southern jet stream can be found running from California to Texas and Oklahoma then into the southeastern states.

On 26 MARCH 1971…  the   weak disturbance in Kansas with the Upper Low has developed significantly and is now showing in negative tilt  in the short  wave trough   — SEE BLACK  LINE–  running from   eastern KY  to the Florida panhandle.  Notice here that   AGAIN the northern jet stream does not drop or phase into the southern jet stream.   By 27 MARCH 1971   the   southern   short wave or Low has moved off the Southeast U.S. Coast into the southwest portions of the north Atlantic.

And finally the snowfall map for this event in late March 1971 showed a large area of   8  to  14″ of snow  across much southwest …  Central … South central and into Eastern Virginia.   Less than 1 inch of snow   fell in  Washington, DC and  4″ of snow  fell in   Norfolk and Virginia Beach and 7″ fell   in Williamsburg.

==============================================

Significantly  after the    12z  13 FEB operational GFS  screw up… the  12z GFS ensemble on 13FEB was much closer towards the European Canadian and British models scenarios .  Indeed the GFS  ensemble  mean was also focusing on the rapid  propagation or eastward movement of an   next incoming trough into the West Coast and towards the Rockies.

The 0z   14 FEB  Global model  runs became a significant turning point in with respect to the probability of a significant  snowstorm  for   the lower Middle Atlantic region .  The   operational GFS showed a much more organized area of low pressure coming further north along the  southeast US coast and  had  snow/ rain up to the North Carolina Virginia State line for the first time.   This was followed by the  0z  run of CMC   ( the Canadian)  which showed a major snowstorm for    the southern half of  Virginia and southern  West Virginia.    The  0z European Model   run showed perhaps the strongest surface Low  yet  with  significant snows far north as Philadelphia  and Southern New Jersey  as the 0z European Model  has the Low  coming as far North  as  37 degrees N latitude before being turned out to sea.

However the 12z   14  FEB   European model shifted the Low  to the south again.  At this Point I began to focus more heavily as to whether not there  was  any chance for phasing to occur between the two jet streams.

All winter long the pattern has featured a very strong and progressive or fast flowing Pacific jet which has not really relaxed long enough to allow for any sort of serious cold air into reasons coming south from Canada.  Very fast progress of flows are resistant to phasing between the southern and the polar jet.  I stated as such on the  FB   page

FEB 14   144PM..
I have for the last few days of favored the flatter solution as a general overall outlook be cause of this particular winter pattern. The last two winters …if you farted too loud you get a snowstorm the East Coast because the pattern allowed phasing… in fact it forced a lot of phasing or merging between the two jet streams. This result in a lot of big East Coast winter storms.

 This winter as we all know has been a very mild winter because the mean pattern or flow has been coming in from the Pacific not from Canada and the arctic regions. Thus with  THIS   possible event … I suspect that constant Pacific Jet stream energy will keep coming in from the West Coast pushing the Southern System on an easterly or eastern northeasterly track and not allowing it to turn up the coast.

The critical issue is whether or not the strong piece of energy in the southern jet stream over Alabama Mississippi mergers or phases with the northern jet stream. If it does…IF… that would pull the system further north and Northern Virginia Maryland into fairly and New Jersey would see significant snow. IF it does NOT phase then this would favor a flatter solution increase the snow threat for central and sw VA into Northern NC

ON  14  FEB  I  Posted a NOTE on the FB page   “WHERE WE STAND  ON THIS POSSIBLE THREAT   FEB 19-20”.

Withe  respect  to the debate as to whether not the operational run  of the 12z  14FEB GFS    was   valid  or  BS…  recall  this run of the GFS  has the Low coming up the coast and dropping heavy snow from DCA to BOS …  was clearly proven by the  0z  15 FEB  operational GFS which did a another flip flop and took the  Low   back to the south… along the  Southeast U.S. Coast over Cape Hatteras and out to sea.

This new flip flop by the operational GFS   model cause me to make the following commentin disgust on the  FB page…

This is why I HATE the GFS past 72 hours when it comes to East Coast winter storms. The 0z GFS model run was a massive …severe unprecedented shift…   taking  the coastal Low from the Georgia Coast … suddenly 300 Miles to the nw over ATL… From passing south and east of Cape Hatteras to passing west of Norfolk … from   showing NO precipitation of any kind north  Washington, DC
…to driving heavy snow and rain into New York City Albany and will Willaimsport PA. The fact that you may be living in the northeast big cities and the 0Z GFS is the picture perfect and one that you want to see for your location does it mean that the solution is a viable.

 The proof ? …all the OTHER weather models… ALL OF THEM…. did not show ANY significant change in their track or forecast and the updated 6z GFS has gone back to the southeast U.S. coastal solution.

At this point in my statements to   my  clients …I again stated that for Central Virginia and the Richmond metro area this was probably going to be a rain event for at least a portion of the  event  but I could not categorically rule out the threat of snow if the trend for colder  temperatures continued.  And for southwest Virginia up through the Shenandoah this look like a pretty significant snowstorm .   One  of these statements was read  on air  during the morning news show on WRVA1140 AM by Jimmy Barrett.  This prompted one of the on air meteorologists  in the Richmond metro area   to comment that   ”despite  some rumors of snow you may have heard about for Sunday the precipitation will be all rain” 

The  0z  15 FEB    run of the GFS…  Amazingly enough had a another massive model flip flop and reversal…  and now took the  southeast coastal Low  well  inland of New York City and Philly which of course  forced the model  to produce widespread significant rain.   ON the FB page  I Posted the following

FEB 15   117AM  ….    ** ALERT **8 ALERT ** IGNORE THE 12Z GFS RUN … AGAIN ** its way inland andhas rain into NYC….  c onsider   the  GFS  last run 4 runs…   12z TUES flat Low moves off NC coast out to sea…  18z TUESDAY a tad further North… 0z WAY NORTH low tracks over ATL then west of Norfolk…  6z Flat wave off the NC coast …12z  way inland and north!.

After seeing the 12Z   runs of the European …British and ….Canadian models  I    finally committed to this publicly on the FB  page  at 126pm  15   FEB

GOOD SIZE SNOWSTORM LOOKING MORE and MORE LIKELY NORTHERN VA … NW VA Northern half of SHENANDOAH VALLEY MD DE   south NJ

This commitment   to forecasting a snowstorm for the lower Middle Atlantic    was rewarded by it more changes in some of the models late on the   15th of FEB… the 0z   16   FEB Model  runs.  As I have said  many …many times… the  operational GFS is a awful model when itcomes to forecasting East Coast winter storms.   It has a lot of trouble handling Southern  short waves…   it has a lot of trouble  Phasing    the  2  jet streams just to name a few.  But once you move within  84   to 72 hours of the event   the GFS was a much better model.

Sure enough  at exactly 84 hours before the start of the event on12z 19 FEB….  the  new   0z  15 FEB    GFS Model showed a dramatic turn towards the European solution.

at 1108pm FEB 15  i made the  following post  on the  FB page

‎**ALERT *** 0Z GFS COMING IN VERY DIFFERENT FROM THE 12Z GFS RUN and much more like the ECMWF / UKMET

This was supported by the Canadian model  0z  FEB 15   run  and like the  European and the new  GFS and  Ukmet   the Canadian model showed no significant snow north of the Washington, DC area.

The model trend continue to show the southeast U.S. Low moving over or just south of Cape Hatteras and out to sea and each one was coming in slightly colder than the previous run on all the models.  After posting the  12z FEB 16 GFS   model  forecast SNOW map on the FB page   I wrote the   following on the FB page   (  which should of  been  under  NEW NOTE     or  posted  here on the   web site )

16FEB 1205PM …   ** 12Z MODEL DISCUSSION 16 FEB MODEL…. VALID FOR FEB 19 EVENT***   and in this  thread I  stated  that so far No model  was bringing the Low north or   heavy snow into any of the big cities of the northeast.  In addition it looked to me that this was going to be a  sw   VA… eastern KY southern WVA    big snow…  And that the rain could turn to  snow for several hours in Richmond but the lack of cold air was going to be a problem east of the Blue Ridge mountains.

Shortly after I wrote that the new 12z  16  FEB  European model came in dramatically colder even in central and Eastern Virginia.  The European model snow map showed a large area of 40 inch snows even through the Richmond metro area.

131PM  FEB 16    ** ALERT *** ALERT ** 12Z EURO BRING IN COLDER AIR TO RIC CHANGES RAIN TO SIGNIFICANT SNOWFALL SUNDAY AFTER 1PM then moderate to heavy snow until late sunday evening … MODEL says 4 to 8 inches of snow Roanoke Charlottesville Lynchburg Richmond Fredericksburg BUT … BUT that is assuming a 10:1 ratio…. if this happens   the snow ratio will  wont be 10:1  around RIC

At this Point I decide to as time the issue a 1ST  GUESS    snowfall forecast  map   at   610pm 16 FEB .

As   we  moved  into the short rain model  timeframe    snow mounts on many the  models began to increase especially east of the Shenandoah Valley into the Piedmont and Central Virginia as the data turn colder and colder with each one.  This was especially true on the  0z      6z and 12z Model runs of the NAM   and  GFS.  It was  at this point that the  short  range models began to show significant snow developing Sunday afternoon across Central Virginia and continuing  to 1:00 AM on the morning of the 20th.

Significant rain events changing over snow with significant accumulations are not likely in Central Virginia but has been known to happen.  But more importantly  the reason for the colder temperature profiles on the shore range models was because the precipitation and the system coming out of the gulf was moving slower .  This in turn allowed for colder air to move southward lay on the 18th into the morning of the 19th.

On Friday morning February 17 I  did a live on air into view with  Jimmy Barret 1140am  WRVA.  My appearance  followed immediately after the  morning news broadcast which featured the some  clown from the  Weather Channel  named  Ray  Stagick.  I have no idea if this guy is a meteorologist are not   but  if he is…  is he  is a pretty awful one.  TWC  committed to inch of snow  or less at the at  the end of the event for the Richmond metro area.    As you can hear from the broadcast..I  went for  2-4  from the city    East and  4 to 8    west  and  sw  and nw of the city and  10″  in  sw  VA.   Still I suppose I should not complain about the weather channel too muchsince they make me look really good.

021712_Dave_Tolleris_1329486354_16656

During the  morning  hours on  15 FEB  all of the Local  TV stations  the their forecasted  snow amounts for Central Virginia in the Richmond metro area   to  1-2”  while  TV 12 continue to show less than 1 inch.  All the TV stations to agreed that western and southwestern Virginia would see several inches of snow and the media stations in the Charlottesville and southwest Virginia / Roanoke markets played up the threat of significant accumulating snow.  Unbelievably even as  NWSFO AKQ began to mention the possibility of accumulating snow TWC  –The Weather  Channel- still refuse to discuss any other outcome except for a rain event with a brief period as snow at the end across central Virginia.

FIRST  CALL MAP   was issued late in the day on  the 17^th.

It was based on the  short range data which showed a longer  delay with the arrival of the precipitation.  Most of the other forecasts and model data were   premised on the idea that the precipitation arriving   Saturday night before the cold air arrived.  However the shore range models continue to emphasize a delay with each passing run so that most the precipitation would not arrive until Sunday dawned over the Virginia North Carolina State line and rapidly expanding northward towards Maryland.

However this delay was significant because it  allowed the reinforcing shot of cold air to sweep into PA MD  WVA  and VA.  It was  not that the air mass was dramatically colder but the due points were significantly   drier.   The temperature profiles began to show that the precipitation might start as rain or as an Exe but a larger and larger portion of this event over Central Virginia was going to fall as snow  and NOT rain.  And over southwest Virginia the shore range models are really began to crank out some impressive snow totals.

Winter storm watches and warnings    were  issued by NWS  for all of southwest Virginia the southern third of West Virginia and Eastern Kentucky.

LAST CALL MAP   issued Saturday  18 FEB 7PM EST.

This was  where  I made my first serious mistake. During the last   2 runs of the  European model the model snow algorithm  showed significant snowfall  — 8-12”   in  west to  east  Band stretching from southwest Virginia/ Roanoke east across the southern Piedmont stopping just to the west of Richmond.   Even though most of the other short range models    on Saturday did not show Richmond getting over 8 inches of snow I decided to gamble as a war and extend the 8 to 12 inch band of snow into the southern Piedmont and fairly close to the western side of the Richmond metro area.

This was a mistake.  I thought that the model is increasing the  snow fall accumulations because   the model  has  detected  the colder drier air and the  later  start time which meant that more the precipitation  would actually fall was snow and not mix precipitation or rain changing to snow.

During the afternoon winter storm watch is were issued for all of Central Virginia for  3 to 6 inch snow amounts.

Lastly…  Surely after I issued the LAST CALL SNOW  FORECAST map the last row of the shore range models came out and a  dramatically reduce the northward extent of the precipitation and the amount of significant precipitation over central…  southwest   Virginia and Southern  Virginia.  This causes a reaction from  several uneducated weather hobbyists  –  called   weather weenies—that of course posted the radar trends did not support significant snow getting into central and southwestern Virginia .

AS  we  now know  the 0z   FEB 19  shore range model runs were all completely mistaken.  However the shift was so complete on all the shore range models that I decided to issue a reduced snowfall map.  Even if the 0z   FEB 19 shore range models  were wrong it was clear that was not going to  be a band of  8-12” snows from Roanoke extending into going through the southern Piedmont almost to the western side of the Richmond metro area.

SUMMARY

I believe that I quickly deduce the potential for this event earlier than anybody else based upon my knowledge and study of the  differences between East Coast snowstorms and lower Middle Atlantic snowstorms.

I recognize the progress  nature   of the pattern which would force the system to slide off the North Carolina Coast.

 My FIRST CALL MAP  was best and my forecast on WRVA 1140  was spot on.

 One other note…  I did we see several emails from folks complaining that the actual website had not been updated and appeared to be completely unaware that the updates…  were being posted directly at the FB page.  I will have to make efforts to ensure that annuity is aware of this feature.

ACTUAL    SNOWFALL…

I am hoping that by  the end of this storm will go into  the record books  and  with  people …   as another  considerable    success   for me   and  WXRISK.COM .  From back in beginning of the week I  was very cautious in declaring that this was going to be a all rain event.  Initially that sort of assertion bought a lot of ridicule with one of the Richmond TV meteorologists saying     ”That contrary to some omission may have heard this week and storms going to be all rain”

This afternoon that same TV station of course had to carry the NWS  3 to 6″   and Winter Storm watches.

Opps!

Its NOT Luck or  hype or  happenstance that this  event has       broekn my  way.   My  reluctance in the declaring this an   “all rain”    event early in the week   was  based upon a extremely well known history or climatology of Virginia Maryland North Carolina snowstorms.  Much of this information I will be posting and providing on the website over the next few weeks now that I have had a chance to catch my breath .      The fact of the matter is that most  meteorologists out there do not know what I know about   Virginia North Carolina and Maryland snowstorms.   But that  is  not all that unusual .

There a lot of meteorologists out there that know a lot more than   me about severe weather and   tornadoes.   or  atmosphere to physics …
or climate modeling.      But during the winter for me  it is East Coast snowstorms in general  of which I given a number of seminars and talks on and  in particular the difference between a Northeast U.S. snowstorm and one for the lower Middle Atlantic region  — North Carolina Virginia Maryland Delaware.

These two animals are not the same thing.  Sure there are occasions where all of these areas…   fFrom North Carolina to Boston see a  heavy major snowstorm.  Some examples of these  are :  January 1996 blizzard…  The great arctic blizzard FEB 11-14 of 1899…   the much  ballyhooed super storm   of March 1993….  The great middle Atlantic    snowstorm of February 1983 and the Knickerbockers storm from January 1922.  But these are exceptions.

The historic  record setting snowstorms of the lower Middle Atlantic   region  was the    JAN 26-27 1940   VA NC  BLizzard   –  did  not bring significant snow north of Baltimore  into the big cities of the northeast.     That  great storm of record in Richmond and all of central and Southern Virginia    was  REAL blizzard and terem was  a  s severe cold wave which followed.  That storm dropped 22 inches of snow in downtown Richmond ….30 inches up by Lynchburg and farmville…   but only 12 inches in DC and nothing north of the Pennsylvania Maryland border.

The March 1-3,  1980 blizzard in eastern and southeastern Virginia or  the one in February 1-3, 1980  or the one  in Jan 1-3  1980  were all total misses   for  the big cities of the Northeast.    Even the surprise blizzard   of January 25,2000   the  brought     huge amount to snow to of Charlotte   (20 inches )   and the entire state of North Carolina … 1 tom2  feet almost all Virginia into Maryland and Delaware …but the snow mounts dramatically fell apart over the big cities of the northeast.

Most of the meteorologists that I have talked to  and/or get information and discuss these synoptic patterns with me   have agree with the argument that I made back the beginning of the week that this coastal storm would NOT have a chance to turn the corner to come up the coast to bring heavy snow to Philadelphia New Jersey New York Boston and New England.  The reason being the system crashing into the West Coast  would act as a kicker — a force of energy which would show the system over the southeast U.S.  off the North Carolina Coast.

At this Point I am pretty much done looking at various weather models and it’s almost time for  “now casting”.  It is also however time to take a look at possible scenarios regarding my forecast  and  forecasts in general as to    WHAT   COULD GO WRONG:

1.  NORTHERN EDGE OF THE SNOW …  some of the 18z  Models and the   12z Saturday European Model do   have snow getting into Washington DC Southern Maryland  the lower Maryland Eastern shore … Southern Delaware even into Cape May NJ.    But not all the models agree about. There could be   pretty sharp cut off on the northern  edge.  It’s possible Washington, DC could see 4 o 5 inches of snow.

2. LOWER  MD  EASTERN SHORE…  Over the past 72 hours as we have moved into the short range models  …all the data has showed that the heavy snow areas in western .. nd Central Virginia narrow  to   a  “V  shaped  point  “    over the lower Maryland Eastern shore.  Some model data shows that the lower Maryland Eastern shore   may  be too warm for  the snow to stick …   but other data shows  there there  could in fact be a  2 to 4″ or  3-6 ” band of snow  over Dorchester   Wicomico Somerset and Worcester perhaps into southern Talbot and  Caroline  counties of the lower Maryland Eastern shore and   Sussex County in Delaware.

3. DELAYED START TIME …  Earlier in the week it looked  like the rain would come in   before  dawn Sunday over much of the southern third of Virginia and of course temperatures would  still be way too warm for the precipitation to fall as snow.  However over the last 36 to 48 hours the models have delayed the start of the precipitation.   By Sunday g 7:00 AM the rain is just across or along the Virginia North Carolina border.  This allows more cold air to get into the commonwealth  and   this air also  will have   lower  Dew points so that when the precipitation begins   and the  air   saturates   — where the temperature and the dew point meet — it does so at  or  below 32°.

4.   TEMPS  SUNDAY NIGHT IN CENTRAL VA….  I anticipate temperatures to drop down to 32° for most of the storm Sunday evening…  some areas might get as low as 31.  Either way it will be just cold enough for this snow to accumulate.  But  the  snow will  be a heavy wet snow especially the beginning and that will cause   some compaction with the snow on the ground.  In other words suppose you measure the snow at one particular time…  at say   4″.    But then you measure it 2 hours later and it’s snowing like hell  but  you  only   measure  5 inches.   This could be   the  type a storm which presents real problems with regard to measuring snow amounts correctly.

On a sidebar let me point out some problems that exist  with the forecasts that I see from NWS.  Now  I hope this does not come across as a NWS  Bash…  because that is not what it is intended as .  I have gotten a lot of emails and face book postings regarding the forecast for southwest Virginia especially in and around Roanoke  and Lynchburg.  The problem is that the official forecast from NWS is correct.  Roanoke for example is under a winter storm warning for   at LEAST   4-8 inches of snows..  and  the   term  ” at least” implies   it could be little more than that for Roanoke.  That is a GOOD forecast.

BUT some of the NWS sites however do not show that.  As of 5:00  or 6:00 PM  Saturuay …after the winter storm warnings have been issued by the Roanoke/ Blacksburg office …other web sites was still showing this.

As you can see this forecast so calls for 2 to 4 inches.

Many TV and radio stations including some of the weekend idiot weather people in southwest Virginia apparently did not know about this confusion.  So they been telling their viewers winter storm warnings for Roanoke  with 2 to 4 inches of snow.  This of course makes no sense since the criteria for winter storm warning in Roanoke and southwest region VA is more than 4 inches of snow.  I do not know what the problem is but I do know that this sort a communication breakdown is very bad news for professional meteorologist everywhere and for TV and NWS people as well.  You cannot  have one end of the body not knowing what the other end of the body is doing…  This needs to be fixed  right away.

Second I don’t understand the forecast for Lynchburg.  If you look at the zones here in southwest region VA  you will notice that Lynchburg and counties to the north are not in official winter storm watch are warning…  But counties to the east and southeast ARE in a winter storm watch.  This makes absolutely no sense whatsoever.  In addition all the data even the warmest models show at least 6 inches of snow in the Lynchburg area accumulating and much of the data shows 10 or 11 or 12 inches.  Now you could argue that Lynchburg is not to see that would snow.  But how then do you argue that areas to the east which were largely would be a little warmer  — areas such as farmville and Prince Edward county   are in a  winter storm watch?  I sure hope that is fixed soon because that is a busted forecast waiting to happen.

I am often asked a question like  ” what does my  gut say…?”   or   “what is my instinct about this particular event ?..”    My response has been and will always be I do not forecast by gut or by emotion or by instinct .  There are some other well known meteorologists — and a lot of   weather   weenies–  who do that and  it usually results in disaster.  By committing to  one particular  forecast Model or  idea days ahead of time …   their  bias  becomes involved the forecast process.   When one model comes out which shows what they think is going to happen… they  Have  TO  latch onto   to that idea it because they have decided days out to go with that particular solution.  In other  words  by   committing so early  to only solution  one loses  the ability  to think   critically.

DT ‘S MEDIUM  RULE #3…   when  ANY  Model … which has been showing  XYZ   for many consecutive runs in a row…  Suddenly shifts and in 1  run shows  ABC….  The other pretty good that that shift is wrong…  Unless all the other weather models also show the same sort of  BIG shift.

The reason why this rule works is that in the current state of  numerical model prediction   — weather models– they are sufficiently accurate and of high enough quality that  it almost all cases if one model shows a shift of significance the other models will fairly quickly follow suit.
This is why I NEVER  Forecast by instinct or Gut.  This is why   REFUSE  to even  consider   the GFS past 72   -84  hours hours when it comes to East Coast winter storms.      Now that being said    I am sure others e are going to manipulate or lie or change this assertion into something that I haven’t said.     I do  NOT have a problem with the GFS model for certain weather patterns   OR  once  we are within 84 hours.  The  0z 15FEB   GFS  model run  was a massive …severe  unprecedented shift…  sSifting the coastal Low  from  the Georgia Coast …  suddenly  300 Miles to the nw  over  ATL…  from passing south and east of Cape Hatteras   to passing   west of Norfolk … fromn showing NO precipitation of any kind north a Washington, DC …  to driving heavy snow and rain into New York City Albany and will Willaimsport  PA.   The fact that you may be living in the northeast big cities and the  0Z GFS  is the picture perfect and one that you want to see for your location does it mean that the solution is a viable.

The proof ? all the OTHER  weather models did not show any significant change in their track or forecast and the updated  6z GFS has gone back to the southeast U.S. coastal solution.

This is supported by the Canadian and the British models 0Z  FEB  15   runs    as well as the 0z  ECMWF     and  the 0z European  Ensemble….  All   showed  ABOUT  the same  SORT  of thing”    the surface Low  tracking along the SE US   coast   in a  ENE direction   then over   or close to  Cape Hatteras.  There   was   absolutely no supported  at all for the ridiculous  0z GFS . None.

In fact the 0z FEB  15 European model had no precipitation of any kind north of Fredericksburg…  The Canadian and the British models do not have any significant snow north of the Washington, DC Baltimore area.   Again I Hope  realize  that   reporting and  discussing   the weather models does  NOT  mean that   the point I am Making   is   MY forecast..     I am  CERTAIN that this will    event wiill become  a mjaor    Precip  event .

We  saw  the same sort of thing   with the 12z GFS  ..  Another solution which was unsupported by even the GFS   Ensemble .  It became so bad   that at midday   15 FEB  HPC had issued a special statement regarding the bizarre scenarios and solutions being proposed by the 12Z  15FEB  operational GFS run.

From HPC Model discussion-THE GFS APPEARS TO HAVE WORSE INITIALIZATION OF THE TROUGH’S PLACEMENT OVER BRITISH COLUMBIA AND NUNAVUT THIS MORNING COMPARED TO THE NAM/ECMWF. MEANWHILE…THE GFS IS MOST AGGRESSIVE IN ALLOWING AN UPSTREAM PERTURBATION CURRENTLY OVER THE PACIFIC TO CUT THROUGH THE SHORTWAVE RIDGE OVER THE CANADIAN ROCKIES ON THURSDAY…WHICH THEN PHASES WITH THE NORTHERN STREAM AND SLOWS THE ENTIRE GFS SOLUTION. THE COMBINATION OF WORSE INITIALIZATION AND QUESTIONABLE AND EVEN SUSPICIOUS PHASING OF THE SEPARATE STREAMS IS SUFFICIENT TO DISCARD THE GFS

But     the   Model  fiasco   last night with the  0z 15 FEB GFS  and  12z  15 FEB GFS  does  emphasize again why I think the  GFS  model …  with espect the East Coast winter storms … is a  piece of  crap..  Note that so far  NONE  of the other medium   range large scale models has shown any sort of  HUGE  wild  swings   in  6  or 12 hrs time increments.      NONE.

Increasingly this looks to me more and more as a Shenandoah Valley /  western VA….and Northern Virginia snowstorm    then up into   DCA/ BWI  area  and possibly  into  southern NJ  .  Richmond I think is going to be more wet than white but I am not absolutely convinced of that all of the event is   going to be all rain   for  central VA.

The area from Lexington south to Roanoke then down to   Hillsville poses of what I think to be the biggest challenges forecast.  Clearly areas which are in elevated terrain have  much better chance of seeing or staying all snow and clearly areas which are and north of interstate 81 have a even better chance of seeing snow…  Either in its entirety or a mixture of rain / snwo  going over to snow as the cold air is pulled into the system.  Once you move north of Lexington and Lynchburg there should be and of cold air east of interstate 81 so that the rain

Of course if one follows the   12z  FEB  15  European model…  And if you have access to the precipitation panels you  will have  seen that very little precipitation falls north of a line front Richmond to Roanoke Virginia.  However the European  Ensemble is much weather and has a large significant precipitation shield …with    precipitation amounts   of  0.25″    that extends    to the Virginia West Virginia border as well as the Maryland Pennsylvania border and into Southern New Jersey .

There could of course the snow to the north of that…  into Philadelphia and New York City.   In fact I suspect is probably going to be even though as a deceiving most of the TV stations in those markets are not forecasting snow into those cities.  That being said a honest interpretation of the pattern and what the model data has been showing in trending   – again ignoring all 4 runs of   15 FEB GFS    –   0z   6z   12z ans 18z  – shows that this is not going to be tracking up towards Cape COD with a benchmark.  That sort of thinking and analysis is just  outright delusioal   and  shows a  poor grasp of basic meteorology .

That  is not to say there aren’t meteorologists out there who are forecasting that but the data does not support a track of the   Low to the benchmark of   40N/ 70 W.   And more importantly the overall 500 MB clearly does not support that a specially with a large  closed 500 Low over  se   Canada.

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