1210 AM   EST   JAN  4  …. STARDATE    201201.04

Sorry I did not get a chance to pose this update earlier but on January 2 I had sort of a family teenager induced crisis which had to be dealt with. Such is life.
Before we move onto the issue at hand… In case   YOU  did not know there is a pretty serious heat wave and drought underway over much of central eastern and Northern Argentina which grows an awful lot of grain these days– corn and wheat and soybeans as well as some cotton.     This image shows the rainfall for the month of December relative to normal as you can see it’s been pretty bad down there   . But I digress.

Part of the problem with meteorology is that like so many other things … it is also quite susceptible to “groupthink.”     We saw the implications of this with most of the seasonal forecasts during the autumn of 2011. The conventional wisdom was overwhelmingly in favor of it least a normal winter over the central and eastern CONUS or another colder and snowier than normal winter. Of course that turned out to be quite wrong— and this also applies to me.

But now what’ has happened is the pendulum may have swung too far the other way. With the development of some experimental week 3 and 4 models such as the European weeklies and the CFS version2.0 model now available to most energy and grain private sector meteorologists…. there is probably now an over reliance on these experimental models. For example over the past several weeks the European weekly models have consistently showed a prety mild pattern and the European weeklies have for the most part been correct. It has consistently showed +EPO/+AO/+NAO/ -PNA pattern.
However the problem here is that there are significant changes which are now on going across much of the arctic regions which would argue for a break in the persistent mild pattern across North America and Europe.
This next first image shows the overall pattern as of December 23, 2011. Two things are easily discernible on this map… There are two large upper Lows or Polar Vortexes (PV) situated in the western hemisphere. One is located over Greenland and another equally strong and persistent Upper Low is located over Alaska.  These two features produce a +EPO/ -PNA pattern over the west coast of North America which  ensures no flow of cold air into the Conus …. and a +AO/ +NAO which insures no persistent Eastern US trough.   Instead all we have is a ZONAL or west to east flow from the eastern Pacific into the western Atlantic.
In order get the pattern to change these two features HAVE to move. If they stay in their current positions than nothing is going to change with regard to the winter pattern over North America.

Here is the current hemispheric analysis from the European model valid 12z JAN 4.

Again notice the two big large PVs… one located over Alaska and the other one over Greenland.   BUT… by day 10 Euro model from 12z JAN 3 is showing some significant changes which we can see when we compare   Day 10 map to the 0z  JAN   3 map /    to  the DEC 23 Upper air map.       First note the Large Upper Low that over Alaska has retrograde significantly towards far eastern Siberia.   In addition the European model shows the deep large vortex over Greenland moves east towards the UK and the North Sea.   The movement of both of these features allows the European model to developer Ridge over Western Canada and some sort trough over the eastern U.S.

This is supported by the European ensemble.   Note that here the persistent large upper low over Alaska has retrograted across the Bering sea into far eastern Siberia.   This significant move and of course changes the entire pattern over the eastern Pacific and Western North America.   On the other hand the European ensemble model at day 10 does not move the persistent deep vortex over Greenland .  That feature remains locked in place and it will take something more than normal pattern evolution to and get this super + AO and +NAO to breakdown.

The movement of the large upper low/ PV over Alaska into eastern Siberia allows for a significant ridge to develop over the Bering sea and Alaska in the 11-15 day .    This ridge builds into Alaska and far Western Canada and also ensures that the vortex over eastern Siberia can not change course and move into Alaska.    This sort of change the pattern is SIGNIFICANT when you compare to the pattern of Mid DECEMBER. And this is now supported by the GFS ensemble mean which we can see here.

We continue to see a slow downward trend in both the phase of the AO and the NAO…. towards a neutral alignment by the middle the month. Again this is a significant change from what we sought in November and December.

Finally in the week 3 and week 4…. the CFS V2.0 Models show a return to a near normal pattern for the last two weeks in January.   As you can see the model is developing a pretty strong deep persistent RIDGE   in the far eastern Pacific just off the California and British Columbia Coast.     In addition the large persistent deep anomaly at 500 mb that has been over Greenland is gone and has actually shifted south into Hudson Bay.    With the overall lower Heights across central and eastern Conus… Temperatures should run cooler than they have been and this is supported by the temperature forecast for North America for week 3 and 4.

SUMMARY:…. Clearly the model data is showing significant changes occurring in the arctic regions during the next two or three weeks. Some of this may be due to the impressive stratosphere of warning which is now underway over the entire arctic region. In order to get a very cold and or stormy pattern we need to get that polar vortex out of Northern Hudson Bay were Baffin island and force that feature to shift well to the south. Right now none of the model data is showing that happening… But that doesn’t mean the PV can’t or word drop south.

1800  EST    28 DEC ….    STARDATE  201112.28

As somebody who works in his own home office  and   owns  theor own business…  I don’t get a lot of days off.  Even when the weather in the Middle Atlantic states is fairly quiet there  is  ALWAYS weather  to talk about which I have to cover for energy  and  grain clients.  So the holidays for me is a big slowdown and much   needed one.  Unless of course you have a major East Coast snowstorm or blizzard like we did last year…  In which case it’s a lot of fun but it’s very intense and it’s not really a break.

Even in this relatively quiet in on eventful winter so far across the eastern half of the CONUS I am watching the developing second heat wave of the growing season for Argentina…  Another round of flooding rainfall likely for much of eastern  and central Brazil…  as well   weather  in Australia and South Africa.. and the   winter  wheat crop  in the Ukraine and  sw Russia… and … and … and…

By now mostly you  have probably heard about the potential for a significant if not major East Coast snowstorm on January  3-4.     On Monday and Tuesday  the  0z and 12  runs of of the European model one bonkers with the development of a major storm on are just off the East Coast and a huge amount of snow.     The 12z  European model on Tuesday  12/27 showed a huge amount of snow  — 12 to 18″ in a band from the Virginia North Carolina border all way up the Boston.

I debated about whether not to post this map because I know is going to cause problems one way or the other.  But I decided to post a map for number of different reasons.  There were 3   primary  reasons   WHY  I decided to issue the European snow map from yesterday.

1.  as I  am sure you and all of your friends and family KNOW …it has  been  a really mild winter so far  especially given  the last two winters    (which were pretty active if not downright severe the times).  So if we were to suddenly see a significant or major East Coast winter storm it could catch a lot of people by surprise.
2.  The European model yesterday showed a lot of snow not just a few inches…  so I wanted people to understand the gravity of the potential significance of the storm if it in fact develops.  I suppose some people are going to accuse me of issuing of that  snow map from yesterday’s European model in some sort  efforts to increase the web site in the face book the viability/ visibility and or  Donations…  but really that has little to do with it.
3.  I try not to talk down to people if I can avoid it.  That’s not to say I won’t rip somebody in new body cavity   if they deserve it.   I  certainly  will do that I  think I need to.   But when I issued the European snow map from yesterday’s model run I stated quite clearly that this was NOT a forecast of some of projection.  For the most part most people understand what I am talking about.  If you are stupid you probably shouldn’t be on the Internet anyway and decides the great thing about stupid people is that it gives me an opportunity to   crap on them.  I could have played it safe and not issued the map because I know that it would cause some confusion…  But quite frankly the culture is stupid enough as it is and I rather not be a part of that since I am supposed to be a scientist and not a    game show host.

Of course once I issued the snow map I guess it was inevitable that the model data early on Wednesday morning and on Wednesday afternoon would turn the other direction and shift the potential major   East coast Low   further off the coast  ( to the east).  Given that this event is still 6  or 7 days away I don’t consider this sort of model shift or variation to be of any significance.  The important thing is that the system is still there  on  all the weather models.

On the other hand it  should be kept in mind that this is NOTHING  like the last two winters.     Over the last two winters the pattern set up early and locked in and a really did not change until spring or late February.     In the winter of 2009-10  and 2010-11   if  you farted too loudly  it would  might cause and East Coast snowstorm to develop.   That is certainly not the case so far this winter.

I have  been asked a number of times to comment  with regard to  the debate as to whether not   the pattern  NEEDS  to   have a  -NAO  to a   East coast snowstorm.  Like many things in life there are several nuances to this question.

If the question is does there   “need”    to be  a -NAO   for any accumulating snow    in the  Northeast  ( VA to  MAINE)    then the answer is clearly no.     We certainly can get accumulating snow of the few inches  with a  +NAO.

But IF  the question is     does there NEED    ( required)   to have a -NAO  to have    S.E.C..S   (significant East Coast snowstorm)   a  M.E.C.S.      (major East Coast snowstorm)  or H.E.C.S.     (historic East Coast snow storm)       then the answer is yes you do need one  9 times out of 10.

For example if we take a look at the   OCT 29-30 NOREASTER that dropped the historic early season snowfall over the higher  terrain   of the northeast and caused tremendous damage in places such as interior Connecticut and western and Central Massachusetts…  we can a  very clearly  see  a   defined  -NAO and  a clearly defined   50/50 Low as well.

Without those two features the October 29-30 NOREASTER would   have come much further inland.  Indeed that has been the problem with all the potential Low pressure area systems so far this winter coming out of the Midwest.  The AO and NAO have both been consistently positive and the times extremely positive almost off the chart…  So Low pressure systems coming out of Midwest have tracked up either through the eastern Great Lakes OR up the spine of the Appalachian Mts.

Indeed this chart shows the actual status  of the   AO and the  NAO since September 30.  As you can see only   TWICE  in the last 90 days has either the Arctic oscillation or the North American oscillation dropped below zero and a negative territory.      And  one of those two times …in late October ..allowed the historic NOREASTER to develop with the inland heavy snow.

In this next image we can take a look of the day 9 European vs. the GFS   from  12/26…  Valid  for January 5.  The map and less hand side is the European the map of the right hand side is the GFS.

Clearly these two maps  do NOT  match as the European model is showing a major trough on the East Coast and the GFS to showing a huge ridge covering the entire country.   But as we can see now from the current GFS model ….  here we  are just two days later and suddenly the GFS has a monster trough on the East Coast  with all sorts of arctic air  coming south covering all the Midwest and northeast and pushing into the Deep South .

If we keep this sort of model failure by the GFS in mind…  Then if the 12z gfs  model today has  no storm near the East Coast  I have to allow for the possibility given the poor performance of the model over the past 48 hours …..that the GFS is probably not handling the situation for January 3 correctly.

That being said the European model also is further East off the coast

as is the 12z   Wednesday Canadian.

But again as it mentioned above at this point in time the issue is whether not this low was still there at all.  And the system is still clearly there.

What about the  + NAO?  Well that’s a good point.    As I stated above if you want to have a really big east coast of snowstorm     one needs to have  either the   AO  and / or the NAO  in negative territory or at least very close to neutral .

Interestingly    as these   charts   from DR Ryan Mauve’s fabulous website shows  the NAO and the NAO   do actually dropped very close to neutral early in January at the time of this potentially   east coast Low.  It is still possible though unlikely  that the  NAO MIGHT   drop into  -NAO  …  Just barely into negative territory–   as we saw in  OCT 28-29.

Regardless of whether not the East Coast snowstorm actually develops or whether it stays out to sea the interaction between the large cold High coming down from Canada and the coastal Low… will produce a strong and prolong lengthy   North wind  from Quebec Canada down to Georgia JAN 3-4.  The cold air that gets pull down because of   depth of the trough  and  the strong North winds is going to shock  a lot of people.  The coldest morning   the East Coast will depend on whether not there is an East Coast storm so it might be  January 4 or January 5  once the winds drop  off .  I would not be all be surprised to see a lot of temperature readings in the single digits from Virginia up into the big cities of the northeast.

Taking a step further out …  we are beginning to see some signs that the pattern may be changing a little bit.  Right now everybody and his mom has January as a blowtorch but if you look at the 11 to 15 day GFS  and  European  ensemble  means they are not that warmed east the Mississippi River.

The European and the European  ensemble at day 10…  show the development of a strong ridge over Central Asia that pushes its way northward across the Arctic circle  and  into   and over the North Pole  by  day 10.  The  12z GFS ensemble  has this as well.

These image  Here   SHOW  how   the BULGE in the     Jet stream over  central  Siberia  Builds into the  Arctic    very  rapidly and strongly   Day  5  to day 10.

This feature does several things.  First it forces the polar vortex to split apart into different sections which in turn weakens the very strong and persistent +AO.  If this projection of higher  heights were to push into Greenland for example it could cause entire pattern to rapidly shift around.

Indeed  if you look at these MECS images you will see a persistent downward trend on all the models with regard to the AO and NAO  over the next two weeks.  It’s a slow steady drop not a massive swing or   oscillation which is one of the reasons why it’s probably going to be the correct overall trend.

1800 EST   20 DEC 2011…. STARDATE   201112.20

There are two things to talk about in this update as the head into the long holiday weekend.  First the potential for East Coast storm of some type during Christmas day.    Earlier in the week I   thought the system would stay flat and undeveloped and not really be a problem for the East Coast but clearly that  is not going to be the case.  The last several runs of the European model of been pretty bullish with the system developing as a wave of low pressure on the cold front on December 23-24 over the southeast   states.  Initially there is  a large cold High centered over Maine and the atmosphere appears to be cold enough for the precipitation to begin as snow   from DCA to   NYC …  but  ONLY  if  some  precipitation breaks out   ahead of the main Low.   This  kind of precipitation event is refer to as overrunning in the weather business.  So  it is possible that IF  the precipitation begins early enough from DC northward into New York City early on the 25th it might begin as snow.  But this is just a maybe and not  yet   a  “probable”  event.

However the overall data clearly shows that the cold High pressure area is not going to stay over southeastern Canada.  Because there is no blocking over the Canadian maritime provinces because there is no blocking in the jet stream over Greenland the cold area of high pressure slides off the coast of very rapidly as the low pressure area is coming up from Georgia and the Carolinas.

The interaction between the Low pressure area and the HIGH  moving off the Maine Coast produces a southeast wind which is the proverbial kiss of death for anybody wanting a snowstorm in the I- 95 corridor.  In order for this to be a snow event for the I-95 cities  the cold High pressure area has to stay over southeastern Canada   AND  the Low   has to track NOT over  Atlanta  but along the GA  SC   NC  coast.

One could argue that pay it still four days away and maybe something will change.  But if that’s what you are thinking then you’re not thinking very clearly.   The issue is not  which side of   Philly   the  r/s   snow line will set up.   At 120  or 108 hrs the weather models are really quite good at this  distance  in seeing he major large scale synoptic features and it is these large scale features which is what sets up snowstorms and nor’easters.  In other   word its  not going to  change   too much.

In the 6-10  day  things still look   like   crap if you like snow and  cold and stormy patterns

The second issue has to do with the longer term pattnern  and  speculations about  the rest of  WINTER 2011-12.  The models continue to show that the  SSW   event is   still developing and it will continue to do so as you move into January.  But one of the things we have to keep in mind is that there are   several  cases   where  of SSW– significant stratospheric warming-  events that have not led to major pattern changes.

The key appears to be whether not the warming at the top levels of atmosphere  – 10 mb  30mb   50 mb  can  move  down into  the   200  300 or  500 MB level.        Keep in mind when we talk about a Greenland block   or the -NAO that what we are actually referring to   is a buildup of warm air at the high latitudes in or near the Arctic regions which causes the Jetstream pattern to shift or change.  It is literally a bubble or mountain of warm air   –relative to the rest of the air around it –and the Jetstream is correspondingly altered .

This image shows what we need to see happen over the next 10 or 12 days   in order to salvage something of the winter.  The BOTTOM hart shows the most important image….  Right now the winds continue to blow from south to north at the high levels of the atmosphere.  Over the last several days we  have seen a slow shift  in these  arrows   from   SE/ NW   to  its  current  South to NE  .   Ideally we want to see the arrows continue  swing  around in a clockwise direction so that they are blowing in a   west to  east or NW to SE   or  even North to south direction.    If this happens then will  see the warm air associated with the SSW  work its way down to the  200 mb  300 mb and 500 mb level and alter the pattern.

Keep in mind however that even IF this is the case and this does happen ….it would not happen before January 10.  Then it would take  another 10 days  after that  before we would see any changes in the pattern.
This is why you some other private forecasters are  now  talking about January 2012  featuring more  very mild  temps  and  a relatively calm pattern.   Even if we do see a shift in the winds at 10mb  30mb  and 50 MB  and the warming getting down to the  200   and 500 MB levels  it  is not going to appear  on the Models  before the middle of January at the earliest.

And there  is also an equally good possibility that the winds never swing around  to a   NW- SE   direction.

2200  EST   13  DEC    …STAR DATE    201112.13

There has been a lot of talk recently from various whether sources and  some of   my   competitors about potential for a pattern change   coming  after the  Holidays.  This talk in part has been based upon the appearance  of a significant bubble  or pool of warm air which appears  in many of the   weather Models   late in the  6-10 day and in the 11-15 day at  the top of the atmosphere   (the  50 mb  level).  The technical name for this phenomenon is called a Significant Stratospheric Warming Event    — which can be referred to as either SSW  or  SSWE — event.

Back in the late 1980s and throughout the 1990s there was a lot of research done on this phenomenon because it appears to have some fairly strong correlation to colder patterns developing over North America.  Without getting too technical the argument or theory goes that the rapid warming in these  very top layers of  the atmosphere enables the middle and lower levels the atmosphere too warm and  thus form blocking patterns.    Keep in mind  for  example that   the -NAO  is   ACTUALLY  a  mountain of  air  that is  much   warmer   (relatively speaking )  then the air  around it.   Then research shows    that about 10 to 14 days after  the  SSWE   reaches  the   high northern latitudes or the arctic circle  the  AO and NAO  turns    negative.

This link shows you the actual breakthrough study when it first appeared back in 1986.

http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%281988%29116%3C0162%3ASSWAAU%3E2.0.CO%3B2

These two images show the impact of the SSW on the Low  pressure tracks  in  JAN  and  FEB.  In both images the top map refers to  NON  SSW  events   and the bottom maps   refer to   Low pressure tracks  for  SSW  events.   As you can see the the tracks are significantly altered in SSW   events  to the south which in turn allows for colder weather patterns and more wintery precipitation.

In this next image we can see   the difference in the month of January and February between temperatures with SSWE    and  Non  SSWE.  In both months large portions of the eastern  half of the CONUS are significantly colder…

This is   GRAPH that   shows   what was  a  MAJOR   SSWE   back in the Middle of winter  of 2008-09 .  As you can see  the RED line  shows the  temps at   50 MB   dropping   in OCT  NOV  DEC… then a     massive rapid   warming   that occurred in   early January  and  the patern shifted.

Here is the  TEMP anomaly  map from DEC  2008  …  and  you can clearly see   temps   much above Normal  over  the  East coast  into the southeast… and    BELOW/ MUCH BELOW  NORMAL   temps over    the Upper  Plains and    Upper  Miss valley .  If you look at the   Upper air maps   you see  +A0 and +NAO   and a  deep persistent Midwest trough    ( sound familar??)

Now   here are  the  Temp anomalies  for     JAN 2009… and  you can see   temps MUCH  BELOW Normal over the    Ohio valley and   New  England and    BELOW  NORMAL  from TN and  NC  northward.    And the maps shows   clear – AO and -NAO and  there were 2   significant  East coast winter  storms in JAN  2009.

If we take a LOOK at the  current   AO  and NAO  trends… we  see  that since   SEPT 21 .. only Twice   have the  AO and the NAO    reached  negative values and even then it  was  for  very brief  time.

These maps show   the  GFS    the CMC and   the much   improved NOGAPS  models forecasts of the AO and NAO.  As you look at these    graphs    Note  how many FALSE  trends   we saw with these models…  how many times     the GFS or   CMC showed a  downward trend  with the   AO    and / or the  NAO… only to be 100%  totally  WRONG.

WHY have these models  THIS winter  been   soooo  bloody  awful with   getting the AO and  NAO  trends  when last winter these same Models  were VERY good???

IMO    it   has  been the   HUGE  massive pool of super cold air  at    the  top of the atmosphere  ( 50mb level)    that has    been a stonewall  against   any attempt   to get the   super +AO and  super  +NAO  from   dropping into the   Negative   phase.

For example  here is the  CURRENT    50 MB   temp  map….  as You can see there is a huge pool of cold air   over  GREELAND … hello  super  + NAO)  and  the   arctic circle  which is  EXACTLY   where the  PV has    been and wehre all these  super    powerful large  Ocean Low   in the northeast Atlantic   have been forming and  battering Ireland  the UK and Northwest Europe.   But  also note the   large  Bubble of  warm temps over    eastern  Asia / Japan

By Day 10  we  can see  Massive     changes  at  500 MB… the   Massive warm  Bubble has   reach  northwest Canada  and the  pool of super  cold air   that was  over  Greenland  and   left the entire westerm Hemisphere  for the 1st time   60  days.

The  day 10    euro   shows  this    huge  bubble of warm air  moving  deeply into  Northern Canada  and buidling into  Greenland  ( a map which I cannot show)

The  11-15  day  on the  euro ensemble are MAXED  out… and off the charts  over   far North  Canada  and beginning to spread into  the  Canadian side of the  arctic circle  and   Greenland.

SUMMARY  this sort of massive warming  MEANS  something.   It  is hard to see   how this pattern  will not be  altered   by this  SSWE.  ASSSUMING   that is  true  the   model data  should  begin to show a   pattern  change    DEC 26-31.    The potential    exists  for the pattern   to  turn much   colder  but   it is far too  early to   commit to that at this time.

LAST   CALL   MAP

This   LAST CALL map   has some  changes on it…   the   these  two  imnages  show  why.   The  first image shwos the     change in the NAM model with regard to the 850  mb Low… the  closed    Low   which  was NOT on the   12z DEC  6 NAM    …  IS  over    central MD     at the  same time   on the 0z  DEC 7   NAM   run. This  has   serious implications  as the   warm air   ( the red lines)    surges  deeper  into   eastern  PA   and into   NYC  and  southern new  England.     As a general rule having an 850 Low     track   North of  DCA and   over  PHL….   The  SECOND   map   shows  how much faster   this   Low   is   coming   up the coast  and that  means LESS    snow    time  once the cold air   arrives.

1ST   CALL MAP … usually issued   36  to  48 hrs before the event begins

In a lot of ways this is turning out to be interesting little event because it will be instructive for those wishing to understand the intricacies of forecasting snowstorms and the northeast U.S..  There are several interesting aspects to this event has is developing.
One of the things you find from meteorology students and those weather hobbyists that are severe weather fanatics  and those  that in general focus   on    the  short term… is that their general ignorance   or lack of focus on the large scale synoptic features can often lead  them  into  ” trouble”  when it comes time to actually making the forecast.  The applies  in particular  Winyter  weather events and    tropical cyclones.
In this particular case  all of the models today have slowed down the arrival the cold air in the big cities of the Northeast.  So obviously the question is why and is this solution viable  and  correct?  Often times you  will see weather hobbyists and inexperienced meteorologists argue     about  the various weather models as to which solution is correct.   And   can  that approach  can  be useful   even for  veteran    Meteorologists.   BUT   if you are aware of the   synoptic pattern  some of these uncertainties  can be answered.
For example currently the temperatures across much of central and Eastern Virginia are in the mid  60s  and a few places have reached  70.   And that is with overcast skies!  That is considerably warmer than what some of the forecast models are calling for just a day or two ago and it represents the strength and the power of the strong rage over the southeastern U.S.
Meanwhile the cold air west of the front over the Midwest and the Ohio Valley is not looking that impressive. Its  there   but  it  is clearly in  no   hurry to come east.  And if take a step back and look at the even larger scale..  We see several real problems here as to why this is not a  I-95  snowstorm.  The extremely positive  AO and NAO… the lack of   50/ 50 Low… the fact that the Low comes up the front BEFORE  the cold air arrives…   and the    veryt fast     track  of the Low Up the coast …all of these things indicate reasons why the snow mounts forecasts even for the high  terrain  to the north and west of the big cities of the Northeast have to be kept on the low side.  We are not in the same winter that we saw last year   or even the year before….  so  it is   imperative that forecasters do not become   Bad  Gnerals and forecast the last battle   or   the last war.

WHAT CAN GO WRONG ?  Is it possible that the cold air might come and faster so that there’s more out of the snow window over the big cities of I -95?  While perhaps but we are getting very close to the that now and so far of anything the model trend is going the other way.  And again here the  the Synoptics are  very  strong  against the idea of the cold air coming in sooner.  You can hang your hat on that miracle if you want to but that’s not the way  I am  going.

Is it possible that the coastal Low may slow down some?  Yes that is also Possible …  but again absolutely no model data showing that occurring and the pattern is  strongly  against  that idea.
The biggest concern for potential busted forecast here is that the precipitation shuts off BEFORE  the cold air arrives.  This would occur if the coastal low war to move faster   or    if  the cold air crossing  the mountains would   be delayed.   Given the overall setup here I think this is the biggest concern   that   would  lead to  a ” busted forecast”.

1ST    GUESS  MAP

 click  on the image for  full size

2050 HRS  EST   1  DECEMBER  2001… STARDATE  201112.01

 Being on the wrong side of a cold front is not a disaster.  Being on the wrong side of a ridge  and having the cold air fairly close to your location—-  and assuming you are a winter  weather lover–  is also not a disaster.  You know what that’s called?    It’s called life ….or in this case weather life.  The important thing to see  is

1)  is there is any colder being generated and  
2) if  so… is the cold   air coming south
3)   and  is  it  reaching  into any portion of  your region.

If  you  are a  winter  weather lover  I am sure  you can recall  that there  have been some notable winters over the last 20 years which have been quite mild and very little snowfall.    What  could  be call a “disaster winter”    if you happen to love winter weather.  For example the winter of 2001 -02…  clearly qualifies as a “disaster winter “.  There was  no cold air being generated and when the cold  fronts    came south     they  had  no  “kick”   to it .     The same thing can be said for the winter of 2007-08.

So even though there are many winter weather lovers…  some of them    in the  various weather forums …   seem to be  about  ready to put a gun  to their   deformed  skulls  because December 1 and they do not have  2 feet of snow on the ground.    Iin my view there  is absolutely no reason to panic or really get worried.

That being said I do have to admit that the entry I made a couple days ago on the FACEBOOK  about the potential for serious cold in the eastern U.S.  is probably not going be nearly as significant as what it appeared.        The primary  reason   for this   is  the     first   cold front which I originally thought  was coming  through  the East Coast December  5-6….   is  NOT  coming  through until  DEC 7-8.     The Upper  Low over the southwest states which alll the Models   have coming out this weekend and brings  significant rain and snow to the drought areas of Texas Oklahoma and Kansas …  is going to come out in one big piece.     It is likely to generate a significant surface Llw over the Delta and Midwest DEC  6-7….  which in turn causes the cold front to slow down and helps pull up mild air across the East Coast.     On the other side are front this system has the potential to bring pretty good snow in areas such as  MO… St. Louis    central and Northern ILL…  Chicago into the western Great Llakes.

Eventually of course once the Low pressure area does move up off the New England Coast the associated cold front sweeps through and the cold air reaches the East Coast DEC  8-9-10.

Up until this point all models agree.  Then things fall to hell in a handbasket. 

Let’s start up are taking a look at the  WRETCHEDLY  bad   operational GFS at 12z   DEC 1  run…. at  240 and  at  360 hrs.     In this image we can see a comparison between the operational GFS  500 MB   map  (left  side)    and the GFS  ensemble  BOTH  valid at day 10.  ( right side).    Clearly the operational run has a solution which the ensemble mean  does NOT support at all.  The operational run shows one conditions covering much of the eastern U.S….  Very warm over the Deep South in fact and all the cold air bottled up across central and Eastern Canada.      MEANING –   reject the operational GFS.

Next lets  take a look at the day 15 operational GFS a compare to the  GFS  day 15  ensemble.  Again we see the same sort of thing where the operational run is vastly different from what the GFS ensemble is showing.

 Lets look at the   operational European  in detail. vs  european ensemble.      This image shows us the  Day  10  500 MB    map of the operational European  (left side)   and the  surface  map for the day 10 european ( right ).     As you can see there   is a lot of cold air  coming south of the European  behind the cold front.     East of the front is a lot of warm air over the southeastern states push and all the way up the East Coast past VA and up into New England.  On the other hand this looks like   a major snowstorm for the upper Midwest and the western Great Lakes.

This image compares the   day 9  operational european Model  (left side)   vs the   day 9  operational GFS model.  In the overall sense both models are very close to each other in the pattern across the entire northern hemisphere.  The only difference is that the GFS has much more ridging over the eastern CONUS    than the European does.

With the European model we see some of the same sort of thing.  The  ensemble    is colder than the  operational or regular.    The euro  emsemble at Day 10   much like the  GFS   ensemble  shows a stronger ridge  over Western Canada and the eastern Pacific and a deeper trough over the central U.S.    The strong southeast ridge g   appears to have moved out into the Atlantic Ocean and there is a   strong   PV over Baffin island   (+AO).

All this is telling me that the 6-10 day timeframe  – dec  7-11…  is probably going to be colder than the operational run of the European or the GFS is currently depicting.  It could be very cold for the upper Pplains the Midwest and seasonally cold for the Northeast.

Looking at some of the   Teleconnection indices.  We can see that in fact the  current  +PNA does weaken over the next several days but tries to make a comeback by the end of the  week 2    on both the European and the GFS  Ensemble .       All of the NAO  indicies stay very positive on all the models…  and the  EPO  turns  slightly negative over the next several days as the West Coast ridge tries to make a reappearance   then turns Positive   as the   west coast ridge  weakens.

 
So again if you  are the northeast   and  looking for a really great early winter pattern there is nothing here which indicates that its  coming.      On the other hand as long as you are  smart enough  to  NOT  pay attention to the operational GFS   past day 7…   there is nothing  in the data which supports  a prolonged  serious warm  periods  — called a  “torch”   in  the weather  Biz.    In fact   for good portion Midwest and the Plain states …the next 2 weeks  looks pretty cold  with a couple of possible significant  winter storms.

In order to break this pattern we need of course  to   get    -AO and or  -NAO  to form .  There is   NOTHING   on the model data which shows   that  happening over the next two weeks.     If we take a look at some of the MJO plots…  we might get a clue as to when the next phase  or development in the winter pattern will occur.  This image shows the current MJO impulse as of November 30 and as you can see  it is in Phase  3. In  December Phase 3 corresponds to a pretty mild pattern  but we are trying to figure out where the  MJO  is going to track.

This next image has four different  MJO  forecast plots on it.  Ideally we wanna get the current MJO impulse to swing around in the phase  7  phase 8 and  phase 1….  This would trigger a significant change in the overall pattern across in northern hemisphere.  As you can see from most of these  MJO plots  they all KILL   the current   MJO   impulse once it moves into phase 4.  They turn the impulse into the circle of death where dissipates.  From there it’s possible we may get a whole new impulse …OR   there  many be  a  new  MJO  impulse    that re-emerges  in another quadrant.

 One last thing… In case  you did not know–  and I am sure many of you do not– the global models in Europe  — the European the GFS the Canadian the British the navy model– are all showing a humongous and extremely intense low pressure area tracking across the northern tip of Scotland and slamming into southwest Norway and day 8.   The 0z GFS  has a MSLP of 933 MB!!!!

 The PSD    Version of   the  GFS shows how this  might lead to something  significant on the road.  During the 6 to 10 day…  As this huge storm moves across the northern tip of Scotland and into southwestern Norway an equally strong positive  500 MB height anomaly will be over the northwest Atlantic.  After the huge storm crashes into Norway it  will track to the Baltic Sea into Southern Finland   or  northwestern Russia during the 8 to 14 day.   This of course will leave a gap  or a  ” void’  in the pattern which will allow the positive  500 MB  anomaly over the northwest Atlantic to move east or  Northeast.

If this  feature moves NORTHEAST   …IF…IF…     it could reach Greenland and trigger a   -NAO   phase / event.  If this happens it would not be until after week 2.    Then   once the  positive  500 anomaly  reaches  Greenland (hypothetical )…  It would take 8 to 10 days before it would affect the pattern over North America .  So if this hypothetical does in fact work out we would not see a significantly colder or more favorable winter weather lover pattern  until around Christmas .     On the other hand it’s also quite possible that this  500  positive anomaly may move due east across the north Atlantic into the UK and never reached Greenland.

2045    HRS   EST   29  NOV   2011…   STARDATE   201111.29

I am doing it this evening update because several things have changed on some of the afternoon models which deserve comment.

A lot of the speculation in the weather committee both within the energy sector and those on the various whether forms that the winter is in trouble or delayed or not going to be significant has been based primarily on the perception that this winter was going to get off to a bang upstart… in a manner similar to what we saw last winter and in the winter of 2009-10.

Since that clearly is not going to happen…. a lot of the energy meteorologist and private sector weather information providers have been backpedaling on their winter forecast.  I am one of them …     my  DECEMBER  2011   forecast is probably going to be too cold east to the Rockies with respect to a temperatures….  especially in the area were a have the  -4° F  region.   My point however is that once the energy forecasts became known through the weather hobbyist community it caused a corresponding   increase in the dissipation and expectations   –  HYPE.  Now that we have all   had  to backpedal on that …we  are seeing the same affect  swing the  the other way.

For example even though most of the model data over the past 24 hours have a showed a pretty strong -EPO   West  coast ridge   ( +PNA)    and  downstream  trough  in the  jet  stream over the  Midwest  in the  6-10  day.   But the overwhelming amount of consensus forecasting from the various private weather servic’s  has been that it is not going to last.  In the 11-15  day the   +PNA is going to break down.

In other words  the -EPO will lose its intensity and the West Coast Ridge  will collapse and it will slide back out towards the dateline in the north Pacific .  This means of course no flow of cold air into the  central  and / or eastern Conus and it could even imply a return  to  -PNA   ( West coast trough)    which is the pattern we are  just now coming out of and which has dominated North America since Halloween.

The reason why these private forecast services have been suggesting that is because the model data was showing  that!  In other words   they  are not making this up….

For example here is the  0z   11/29  run of  the ECWMF    500 MB  for  day 9.  As you can see the entire West Coast ridge pattern has completely broken down.

 So then …the KEY ISSUES  are      1)   how  Long does this   cold pattern  last??     2)Does the    +PNA pattern   break down and do we  return to  a pattern like we have seen for much of November???

In my opinion the argument that we are going to see a return to a super warm  -PNA    November like pattern is  wrong because it misses how we ended up getting such a warm pattern.   It is  NOT  the   had   a -PNA pattern and +NAO over  north America. There was something at  play here.

The super warm November of 2011 was caused in my opinion by the development of a large  500 Low– a  POLAR  VORTEX — over Siberia which moves across the Bering sea into Alaska during the month.  At the same time  a Ridge in the North Pacific was trying to expand and push north towards the Aleutian islands and the south coast of Alaska.  These two forces cause the Pacific jet stream to  “COMPACT”  :     we could   be seen by noting the very strong wind speed velocities at 200  MB during the month of November over the north Pacific.  At times the speed   were  up to 200 knots.  This  extremely fast  Pac  jet not only ensure a persistent trough  over the West Coast but it also cut off the flow of any sort of cold air getting into central or Southern Canada.

All that being said it should be pointed out that the  GEFS–  the  GFS   ensemble– has been much more bullish with a cold  pattern for North America.    The Tuesday afternoon /12z    run of the  11/29    ECMWF  the European model change direction dramatically and ends up showing a vastly different pattern the one who showing this morning and one that is much closer to what the  GEFS  has been showing for the past few days.   Even more surprising is that the European ENSEMBLE    agrees with with the  Operational  European and the GFS  / GEFS  ensemble!

To show you how big the changes are let’s take a look of this first image.  There are four maps here….  Both maps on the left side are the Day 9  European  model … on the right side  are the   day 9  GFS  model.   the TOP are the 0z  runs  the Bottom maps  are the  12z    runs.   As you can see the European high showed a huge change  from 0z to 12z  runs.

Now that   this sort of  BIG Model  flio flop is  not always a good thing   because that sort a big change in model consistency especially with a good model like the European can be troubling.  On the other hand the fact that the European is turning towards the GEFS  ( GFS ensemble)   could be significant.

 Here is the   12z   11/29   GEFS at  Day 10.  I have e highlighted some important features here so that you can see why this map is significant.

 By   324   hr    the   GEFS is showing some changes. The   Big  west coast  Eidge   ( the +PNA) has broken down and is moving   (retrograding )  west towards the dateline.  But also note that the bright red area over the azores  at  240 hrs    is  STILL there at   324  hrs. 

 This image shows you the   day 10   euro  from  the 12z  run 11/30.   I have highlighted some features for you to take a look at.  Let me be clear– this is not in any way a   Major  or  a Severe arctic outbreak of cold air.  This is a  good cold   (seasonally cold )   early December looking map.   

But clearly the most important feature on the European is the development of a strong   north Atlantic  Ridge  in the north central Atlantic which appears to be pushing into Iceland and the southern tip of Greenland.    This is not technically a -NAO but by Day 10   it appears to be on its way of becoming one.     Again this is a major change in the European model and it does so because the model develops a strong piece of energy   — a shortwave– that bombs a  surface  Low  off the Gulf of Maine Coast DEC  7.     This Low moves up into   southeast  Canada which in turn causes  the     N  Atlantic ridge to develop and expand towards Iceland in Greenland.

The 12z  European ensemble generally supports the operational European to a large degree.    As you can see the model actually does support the north Atlantic Ridge Building   towards Iceland / Greenland which quite frankly surprised the hell out of me because I thought the operational European was on its own.    In addition the model has slowed down the movement of the  West coast ridge    sliding  back to the  west somewhat.

 To show you what this looks like at the surface  …here is the    large scale  day 10  European map with 850 mb  temps…
 and the   close up  view of  Just the  CONUS and    far southern Canada.    As you can see as cold and over the upper Midwest  and  the Great Lakes it’s pretty darn cold.

Here is the  12z   11/29   run of   the GEFS     500 MB  height  anomalies   for the 6-10 day and 11-15   day.  As you can see that very strong positive height anomaly along and just off the west coast of Canada in the 6-10 day .    IT  does   slide   WEST  in the 11-15 day.    This causes  the cold pattern  to relax somewhat but that does not mean we are going to see we turn to the super warm pattern  of   Nov 2011.

The GEFS does not show a strong north Atlantic  Ridge  expanding into Greenland and Iceland at  day 10 0 or day 13.  Instead the model has a very strong    “Azores  Ridge”.      And that  has  to be  watched because it is  very possible that the relaxation of the excessively stormy pattern in the northeast North Atlantic  will allow this  Azores Ridge  to expand towards  Iceland.

One last point….    The    current MJO impulse does not support a prolonged +PNA   and  true  classic  -NAO.  Most of the  MJO models  show the current impulse weakening as it moves into phase 4  and 5 and then collapsing or dining in the circle of death.  The change from what we saw on Monday and over the weekend…. when the various MJO    model  forecasts showed a strong   MJO impulse.  If in fact the trend is correct and the current MJO impulse collapses this  COULD  allow for a more rapid transition to a new and cold a pattern over North America.

2000  EST  26  NOV  2011….    STARDATE  201111.26

 
While thanksgiving is over  and MOST  the turkey  has been  eaten  so it’s time to get back to the weather biz.      (although I am a anticipating one more delicious Turkey left over lunch on Sunday afternoon)        First I’m extremely happy with the way this weekend forecast turned out.  Up and down the entire East Coast and in to the Ohio and Tennessee Valley this has been an extremely nice long thanksgiving weekend.     I do believe  one could make the case   that this   has  been  nicest thanksgiving weekend in the last 50 years or more!    Given a that I made this forecast  here on the  WEB  page and over on  FACEBOOK  for the  1st time back   on NOV   15-16…  I am  darn happy.

 However when I made that forecasts and in the subsequent updates to that I talked about how of as we came out of the holiday weekend  — NOV 27  –  it could be a difficult travel day for many areas over the eastern U.S.     The ixssue  is  a  slow moving   but important cold front which can be seen crossing the Midwest and the Delta  regions on the Saturday early evening radar.     Over the past several days the weather models have slowed the system down a  bit so that by the time and reaches this maximum intensity it will actually be Monday the 28th.
That being said … the  overall scenario really has not changed …its just a timing issue.     All the model data shows that energy coming into the base of the trough over the Delta region will cause an upper Low to form and separate itself from the main  trough over the Midwest.      When this happens is called a  CUTOFF  LOW.    But in this case… the   cutoff  Low develops a    negative tilt. …which is a sign of a very strong and rapidly developing system   over the TN  and Ohio valleys.

To show you what this looks like  here is the  12z    SATURDAY   GFS  Model  at  60  72  and 84  hrs   at the 500 MB  level.  I have  drawn in the trough axis or the tilt of the upper low and you can see it’s running from the northwest towards the southeast….  which is by definition a negative tilt. 

As you can see here the European models strongly agrees with the scenario as those the British model and the Canadian. 

 
At the surface a second area of   Low pressure is going to form over the Gulf coast states and be pulled northward then northwest under this deep   closed   cutoff  Low .  In addition the strong area of High pressure off the East Coast  — the feature giving  the eastern US   this  great weekend..  will still be a factor.   The  High off the coast will be  feeding  a  significant inflow of very moist air from the southwest Atlantic into the    the entire East Coast  region.    Over the Appalachian mountains    and into   the  elevated terrain  of  TN   and KY rainfall amounts will be quite impressive over the next three days.   Possibly as much as 6 inches a rain and some locations.

BUT then  things  get  tricky.  Note in those  GFS 500 MB  maps how many of those Black Lines develop around the upper Low.     At   72 hrs  the GFS  shows 4  closed contours around this very impressive   “monster”  upper Low.       That represents a great deal of very cold air in the middle and upper levels of the atmosphere  and as result the  GFS   Model shows that the low levels  COULD become cold enough over the high terrain for the rain to go over snow Monday night into Tuesday over Northern Alabama   portions of  Tennessee  into  Indiana   and much of Michigan.

 
For this reason I  have issued a  FIRST    GUESS map with regard to this potential for snow.  This is a very risky forecast and it is quite possible that the cold air never gets down to the surface in time to cause force the rain to change over snow.

Further to the east it  is pretty clear that there is  going to be a large band of heavy showers and thunderstorms developing over the coastal areas of GA  and SC     then  move into all of  North Carolina southern and   western   Virginia…  central Virginia   and all of  WV   and into MD and    western PA.    However as this band pushes to the north and northeast   it  will  weaken and fall apart once  it  reaches central and northeastern Pennsylvania and New Jersey.

Longer term we can see some major changes occurring in the overall pattern.  Of course it may not mean much for your particular location BUT….   if you want to take a look of the big picture there are some things to point out which are significant.

In this image  we can see the  Upper air    pattern  (500 mb)    from November 21 and compare it to the forecast to  the  day 10 European model valid for December 8.     We can see some major differences.    Note that the huge vortex and deep troug in the gulf Alaska and the Eastern Pacific Ocean on November 21 has been replaced by a very strong Ridge  that pushes up to the coast of Alaska!    Also the ridge over the central  CONUS is now being replaced by a fairly deep trough.  The strong Ridge  over Europe gets replaced by a deep trough.      So things are changing.

If we look at some other Teleconnection indices however we see some discrepancies.     If we look of the two week forecast in Trends from the GFS  ensemble   from  the ESRL    web site…  the    regular  GFS  and   the  PSD  version of the GFS both showed the NAO staying strongly positive for most of the time frame   ( perahps  beginning to move towards a Neutral  by day 13-14).   However they do NOT agree on the PNA.       The regular GFS model shows  moderately strong positive PNA  through  day  10-11….  whereas the  PSD version of the GFS shows an extremely strong negative PNA.

Clearly these two things are not the same.  The reason is that the PSD  definition of what constitutes a  -PNA  vs a   +PNA  is not the  same as   CPC/ NCEP definition.

We see the same sort of problem looking at the  Western Pacific   and EPO Teleconnection trends.  Both versions of the GFS are in pretty good agreement over the next 11 to 12 days with regard to the Western Pacific Teleconnection.    But they do not agree   over the  EPO  trends.  As you can see the PSD   version of the GFS shows wild swings back and forth  fromn positive to negative   then  negative back the positive  with regard to the EPO.

One of the ways and getting around this sort of discrepancy is to look of the European model and the European  ensembles.  I have placed the operational European run  at day 10 next to the  day 10 European ensemble.    The European  ensemble has a weaker ridge over the southeastern CONUS      so  temperatures are somewhat colder   east  of the Mississippi River.     But the important thing here is that both  the Operational   Europeran and  the European ensemble  show a very strong Ridge over the eastern Pacific pushing up towards the coast of Alaska .  To be sure this   is NOT   massive  or highly amplified  Ridge…  but it clearly shows  that   the PNA   is going to be in the positive phase   at  day 10.    

Clearly the   PSD   run of the GFS is    wrong. 

If we look at the   GFS   ENSEMBLE  temperatures at Day 7 we can see a lot of dark blue and some purple actually showing up over portions of the eastern U.S.–  mainly over the southern portions of the U.S.  while over the Northeast and the Great Lakes sees seasonal  early  DEC temperatures.   At Day 13…  we  see more of the same…

      Finally I suppose it’s  fair to say that there are TWO ways to look at the first 10 or 12 days of December 2011.  It is clearly not going to be as cold as what some of the private energy forecasters have been calling for.  On the other hand given the fact   that  +PNA is only of average intensity…    the AO  this still clearly positive  as is the NAO…  it is   almost a   miracle  that   Deep South looks  cold   while the   Great Lakes and the Northeast  looks  seasonal for   early    December.

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

1900  EST  NOV  23  2011… STARDATE  20111.23

I am hearing report some various meteorologists both within the private commercial sector and in the energy sector which are either killing off the winter  of 2011-12   over the eastern half of the CONUS ….  Or they are significantly downplaying it.

I suppose to a lot of folks this sort of decision doesn’t make a lot of sense especially given that we’re just now entering the thanksgiving holiday.  From my point of view of I agree.  I think part of   the problem…  may be that the last two winters were so significant over so much of the country east of the Rockies and especially east the Mississippi River…  that many have become spoiled.    And because  there have been  2 significant winters in a row ..the anticipation and build up… the  excitement about the potential for this winter…  especially given some of the early forecast calls…  have all  contributed significantly to ” expectations” .      As a result …IF  it turns out that this winter is not going to be as impressive as the last two winters…  and you have been telling folks  and your clients that  thid winter  WILL be…     well then  you may have a problem.
We now KNOW   that November  2011  will end up  been pretty mild and there  has  been a real lack of cold air over any portion of North America.  Of course as I pointed out in a previous posting November 2010 was pretty mild as well…  So    this current  Mild NOV does necessarily mean anything.  But you have to understand if you are weather hobbyists WHY some of these other forecast services and private forecasters are already  downplaying  and/or backpedaling on the winter of 2011-12.

Essentially they  have been  following the overall pattern and they see the number of things wrong with it and they figure that by the time things change so that we are seeing  even   “seasonal cold”  temperatures  it may be  DEC 10  or 15.   Of course past the past December we still have January February and for most of     the CONUS   a good portion of March as well.  There is just too much data and indication out there   — the above and much above normal snowfall over the northern hemisphere and especially over Eurasia… the  super  warm  North Atlantic  ( the +AMO) … the weak    negative QBO and the   fact that the La Nina  has NOT strengthened steadily or dramatically over the past few weeks    (recall last Sept and OCT   the La Nina   dropped  like a  Rock)   to bail out on the Winter.

So at this point I have not given up in the winter and I certainly have not given up on December still being at least seasonally cold   or fairly close to being seasonally cold for a good portion of the central and eastern CONUS.     That being said some of us are just going to have to get used to the fact the last couple winters have been really good    with respect to  EARLY  season cold and snow for large portions of the central and eastern U.S.     The last 2 winters   really got cranking in December…  but there have been a lot of winters in the weather history of the country  in which December  was   either Mild  or   just OK  ( DEC 93 of the winter of 1993-94  comes to mind)   that did not get cracking until January and February.

If we take a look of the latest MJO plots 

    you will see that most of the Plots   show the  current MJO  swings around   into   Phase   3 and 4  and 5  over the next  2 weeks.    As you can see  here      in DEC    Phase 4 and 5    are    very Mild  temps  patterns  for  the  central and eastern  US.    This would lead one to believe that the mild pattern  over the central and   eastern US  is going to continue into the first 10 days of December.  

However that most of the medium range models do not agree with that scenario.  Keep in mind  tha the  current MJO  impulse   is pretty weak and it  is very possible   that it might  collapse  into the   ” circle of  Death”.

For example here is the first image which shows the DAY 10 European model hemispheric projection  from 0z   FRIDAY  NOV  23.  As you can see it does not show a very promising looking pattern at all.  All the cold air is bottled up across the arctic region and the overall pattern across the CONUS looks pretty darn benign.

 However the   12z NOV 23  European model both at the operational and the  ensemble level    looks  much more significant and promising.  At the operational level we can see  ( the Hemispheric  projection)  a major Ridge  developing in the eastern Pacific pushing  North  into  the Yukon and Eastern Alaska…  and a  rapidly in deepening major trough over Western Canada pushing into the Pacific Northwest and northern Rockies.  That certainly is a major change from the  0z   Operational  European  run!  The day 10  operational  European model    at day 10   shows a  3  WAVE  pattern –  3  distinct troughs over the hemisphere.  

Focusing more on the CONUS  at day 10 you can see the very impressive amount of cold air pouring south at a Western Canada driving across the continental divide  trying  to reach location such as Seattle  and Boise.

     At the   Ensemble Level  Day 10 day    the 12z  European shows a more improved pattern both at the hemispheric level and at the regional level.  At the hemispheric perspective we can see two distinct polar vortexes :  One is over northeastern Canada and the other  is over eastern Siberia.  This is a significant change from earlier in the month when we have the  PV  in Alaska and the Yukon.  In addition we no longer have a deep trough in the gulf Alaska slamming into Western Canada but now we have a “flat” or  Broad  Ridge.  Again NOT  good for  serious serious cold  air   getting into the CONUS   but  its not nearly  as awful when you compare it to what the pattern is look like over the past 10-14  days.

    This can be seen with better clarity on the regional shot  of   the day 10 European  ensemble   map.

It is quite possible that the deep trough over Western Canada will swing through an across the Rockies the Plains  the Midwest and into the East Coast during early in the middle portions of December.  It is also quite possible that the trough may stay over the western U.S.  and perhaps just reach portions of the Plains.    Certainly that is what the  MJO   amd its forecast   of  Phase  4-5  is indicating. 

1800  EST  MONDAY  NOV 21

WED NOV 23    -    this   probably  THE  biggest   travel day     of the year.      You may have heard from some others weather sources    (accu  blunder for  one)   that there might be a winter storm of some type over some portion the northeast on November 23 or the 24th .  Let  me assure you that is not going to happen.  All the model data today clearly moved away from that solution… which given the overall pattern    it   SHOULD  of been clear to   any  meteorologist   that   is was  very unlikely that there was  going to be an  East coast  Low to  begin with.

Basically you do not get a winter storm on the East Coast simple be cause a weather model produces a big     “L  “     along the East Coast.   Besides having  cold air    — which we do NOT  have — there have to be several other features going on in the atmosphere for a East Coast winter storm of some type.  And none of those things are occurring and they are not going to occur next week.

Instead we  will  see a Low pressure area form over Missouri Arkansas NOV 22… track of through the Ohio Valley… into WVA and  western or central PA  NOV 23.   With HIGH pressure moving off the East Coast…  winds will be   southerly  so temps  at all levels of the atmosphere will be much to warm for any sort of frozen precipitation .     We are looking at  Good rains   for  TN  IND KY late on the  22nd    into   PH  PA  on the  23rd  into  southern NY .   Even  locations such as Syracuse Binghamton as well as Buffalo will be too warm for snow .

JUST RAIN.  
There may be some snow over far Northern New York State and Northern New England….  that is to say central and northern NH and  VT  and  Maine on NOV 23 but for the big cities of the northeast  AND    the  Appalachian Mts… this will be all rain.

The Midwest should be clear and mild the entire day on the 23rd as will the Plains   the Delta  regions and the   Rockies.  Anyone traveling the California…   there will be some rain coming in two Northern California and the Pacific Northwest on the 23rd but central and Southern California as well as Vegas should all be completely dry with mild temperatures.

NOV 24  — very quiet and mild weather conditions across most of the  CONUS.  Only northern New England will see any sort of seasonally cold temperatures .     After chilly start in the morning hours over New England   the Middle Atlantic states  and  the  Midwest …. everybody  Easte  of   the Mississippi River will see mild pleasant   conditions for Thanksgiving Day … with TONS of sunshine!!!      New England  will see Max temperatures mostly in the   40s…..  50s  to   60 degrees over   MD  VA  WVA   NC   DE … and over  ALL of the Midwest .  

 NOV 25….  HIGH  pressure moves   off the coast  SO  winds  will become southwest   and temperatures will warm rapidly across all the Midwest and the entire East Coast.      It will be spectacular….  For late November.   Readings will push into the high  60s    or Low 70s  into  MD     VA NC   TN  KY  southern WVA   Low 70s over the  Deep South and    low 60s   for  all of the Midwest   EAST of the Mississippi river .  Only over the  Great Lakes  into  MN and the Dakotas will temperatures be in the   40s
. 
NOV 26 … more of the same.    70 degrees  is LIKELY   for  all of  NC    VA   MD     southern  WVA    Columbus OH    Eastern Kentucky  and into  all the Carolinas and Georgia.    Temps will likely   reach   60+    degrees  ( maybe   65)     into Boston NYC     Albany   Buffalo  and Detroit.       But there is going to be a fairly strong cold front moving across the Plains into the western Great Lakes  ILL    eastern MO   and ARK and LA by midday on the 26th.  This front  will  cause significant showers and thunderstorms .     The showers and storms should reach   eastern  KY  OH    MI  by sunset on the 26th.

 NOV 27 ….   The Models  this Monday  have ALL turned to the idea of   the  Major trough   moving into  the Plains and  Midwest.      The    TROUGH    and the surface cold front will stall   because of   Huge Ridge off the   East coast. 

The  trough   will  develops a   TILT …  NW -  SE   ..which is called a NEGATIVE  TILT.     This Image   from the 12z   European Model  shows  the    Upper air   pattern….

 this Image  from the  12z  shows the SURFACE MAP  on the  evening  of    the 27th 

This is  DANGEROUS  sign   and a clue  for meteorologists  that  this   NOV 27   Low   is going to be a  BIG     DEAL.   The   strong   S   to N  winds     in the Jet stream   over the   East coast … combined with   warm Humid  air   coming in  from  FL and the sw Atlantic… combined with the Cold air  in   thr  Upper  Low  … driving a   strong  cold front   into the   East coast   will  allow for  heavy storms  and possibly    a  major    severe  wx  outbreak    late on the  27th for  TN  AL GA  SC    eastern   KY into  WVA….  then   into     NC  VA  MD  DE   PA  NJ   on the   28th.

 DT
  this will be updated    NOV 22….

1900 EST   19 NOV  2011… STARDATE  201111.19

  A few days ago there was some “talk”   or speculation of a possible East coast Low and some winter weather Wednesday night into Thurday morning.  Of course as we all KNOW that Low is going to track up the Ohio Valley and the Appalachian mountains.   The Low for NOV 23 was NEVER a serious threat for the East coast because of the Deep trough over the northeast Pacific/ West coast AND the +NAO.   The combination of both of these features forces the SE Ridge of the US to stay strong and a INLAND track is the only possible solution.

The same sort of thing will the case NOV 26-27-28.  At Day 7 all the Models show MAJOR trough developing over the Plains and moving into the Midwest.  There will be one Low over the western Great Lakes on the 24th but that Low will “die” and a new Low forms over TN on 27th.  The trough as it bumps up against the HUGE East coast ridge goes
” NEGATIVE” — is tilted NW to SE. 

Up to this point the CMC the ECMWF and the GFS models all agree.

  　  The CMC and GFS somehow or another STILL manage to drive this negatively Tilted trough over the Midwest/ Ohio Valley to the East coast.  This solution is ABSURD and is meteorologically unsound given the overall pattern in North America.   The best I can figure it the CMC and GFS solutions only make sense if Lord Voldermot uses his magic powers.

These maps show the detailed 12z saturday NOV 19 run of the ECMWF for this event.   IF … IF the models are correct inb depicting the deep trough with a Negative tilt the severe weather threat for the East coast late on the 27th into the 28th could be “SIGNIFICANT”.

LONGER TERM… the day 10 euro ensemble shows 2 Polar Vortexes but both of them are NOT in good position for getting cold air into the CONUS.  If this map is correct the NAO is positive and AO is VERY positive into early DEC.  On the other hand we no longer have strong southeast US Ridge and the intense PV that has been over the Alaska and the Yukon is gone. That PV has moved into Bering Sea.  IF it were to keep moving towards the Aleutian Islands that could be a significant development towards altering the pattern.