Posted by wxrisk | GENERAL | Tuesday 31 January 2012 7:08 pm

so much  to say  so much to say   so much to say –   DAVE MATHEWS    BAND.


Really I do.  If you  are a energy meteorologist  or   a TV  meteorologist…   this winter has not been particularly enticing here in the  U.S.     Of course given  that the last two winters have been gangbusters  those two types of  Meteorologists   probably need a break.  BUT if you are  agricultural /Grain  meteorology   –  and I do far more Gain  weather than energy weather -    and it’s been gangbusters  all around the world and helluva lot of fun.

Every single day I am issuing forecasts not just for the U.S.  Plains /  Midwest but for Argentina and Brazil …South Africa… Australia Europe… the Ukraine… Southwest Russia and Kazakhstan and then when their growing seasons are up and running China and India  as well.

wow…. Ya know when  I think about it… I do a lot of work every day.  Plus the  web site and the FB  page.  But really it’s not work at all because if I couldn’t forecast weather I probably starve to death.  Right now for example  much of Argentina and Southeast Brazil bring areas have been devastated by a  drought and three prolonged key ways since mid December.    One location in West Central Argentina  — Santiago Del  Estero — reported a Max temperature of 50°  C   or  122 degrees  F.  Now that reading is probably in error but a lot of  places and Argentina on the 30th sought Max temperature of 40 degrees  C   or 105  degrees F.   However a monster  HEAT DOME  has moved into Eastern Brazil which is  going too slowly drift towards Bolivia and Paraguay over the next several days while at the same time a cold front moves into Central Argentina.  This cold  front is going stall because of the heat dome blocking its path and portions of  Central Argentina could see some pretty good rains…  But then  there may be yet another interval of significant heat in Argentina in mid February!

Now if we take a look over in Russia … several locations this morning January 31 temperatures drop to -28° C /-18F. !  Even more important is that for most of December and January the Ukraine and southwest Russia has seen much  above normal temperatures.  There  has not been a lot of snow cover and some of  the winter wheat crop has already tried to break ground in Southern Ukraine and
southwest Russia.  Now along comes as monster arctic HIGH at  1061 mb  over  Northwest Russia near Saint Petersburg which has spread the cold all way to the  Rhine river!  This morning in Bulgaria  many locations had temperatures dropped to zero degrees Fahrenheit .

If this sounds like I am  really enthusiastic about  weather worldwide…  I really am.  But the truth of the matter is that I get this  excited about ALL weather almost every single day.  As a result I can go out of my way to  post about how warm it’s going to be in the Middle Atlantic states 7 to 10 days out with the same amount of enthusiasm  that I have for a big winter storm.   So while it  IS true  that I do love East Coast snowstorms and East  Coast hurricanes a lot …I try not to let my fondness for those particular type of weather events distract me or by state in any way.  And one of the ways I do that is to get excited about weather which many of you may not feel is all that
great or noteworthy.


Some of you have noted over the past week  that  in the  debate   about the  idea of FEB 2012 turning   colder and  or stormier for the  eastern Conus … my overall perspective  or  attitude    has changed.    Lead me be upfront and frank about this     YES  my perception  and  views  about February 2012 has changed from   from  what it was last week.  Now  some of you…  may view me  as   “Johnny come lately“  to the party as other well known meteorologists have been talking about a much colder and potentially more winter like February 2012 for the last couple weeks.     OK fair enough.

But if you are going to make that same judgment then it’s only fair to note that some of these other same meteorologists have been banging the drum for a major pattern change over North America several times this winter and  as we all KNOW .. it has NOT  happened.    One energy trader made a joking comment  to  me   that this well known private meteorologist up in New England    “has forecasted seven of the last zero pattern changes…”     OUCH…

In the arguments I made  over the past few weeks against the  idea of  a  BIG  pattern change …  I tried  to drive home the importance and the significance of the huge Polar Vortex in the jet stream sitting up north of Alaska …on the Asian side of the Arctic circle.  Time and time again I stated that in order to get a pattern change in North America that feature has to move or break down or shift or do something  …because as long as it stays there  nothing is going to happen  regardless of what any model might or might not be  saying .

Now  we are  finally  seeing that huge Polar Vortex breaking down and changing.  That is why I am  more bullish about February than  I was before.    I set up by specific criteria or checklist of things which I had to see happen  FIRST  before I jump on board.  Now that I see those    things happening my perspective has changed.    To me is not important as to whether or  not to   “call it FIRST!  “   You don’t get extra money …the girls don’t think  you are any  sexier and you don’t dance any better.
I think it is very important to notice that few if any of the meteorologist   that have the  “ call it first  “  attitude never come out and say  ” the issue is uncertain”  or  “ the issue is undecided“.     Yet as we all know small changes often lead to very big variations   as you go further out in time.  Therefore the perspective / goal of always trying to   CALL IT FIRST  can only  Blow   up in your face because sometimes you can not call it First.  Sometimes you cannot  make the call   right now  based on the current data.

The problem is that if you decide to chase the  goal   of   “Calling  it  first “   is the most important thing as a professional meteorologist …  you may get on TV the most  but  in the end     you will  also  get the reputation   of    “forecasting seven of the last nonexistent pattern changes”.   In the end you will end up cutting off  your  nose despite  your face because all  of your forecasts  will be looked at with a great deal of skepticism and of little value to people who have serious money and  would d normally be interested in what you  have to say.

THE FEB 5-6  EVENT….  its coming  North !!!!!

The models at midday are clearly not in agreement.    All the models do  agree that a strong ocean Low was going to form and stall over Southeast Canada/ Newfoundland over the next 4 days .  This deep system will set up a strong  CONFLUENT  flow in the polar jet …  That will allow for a relatively cold area of High pressure over Eastern Canada  too develop  (near Montreal ).  So far so good.
However the European Model with its bias  to develop systems too far to the west …ends up closing off the upper Low over western KS.     At the same time the  Ridge  over the West Coast  of  N America –part of the +PNA    – begins to develop so the Ridge traps the upper Low  over  KS is delayed for several days.  The precipitation shield completely falls apart as  the Upper Low  tries to Under cut the Ridge and move into the Great Lakes.  By the time the precipitation finally reaches the Appalachians and the East Coast the cold air source over southeastern Canada is gone so whatever falls is mild and rain.  I believe that the European solution  for  FEB 5-6  at  Midday  is   NOT   the correct solution.

On the other hand      some   of you  out there  –and I   know you who are   because I have seen your posts on various whether forms–   are arguing that the flat weak Low   on the  12z and 18z JAN 31  GFS solutions   that moves off the NC / VA coast is underdone…  and / or that we will see a bigger Low pressure area come off the coast and it will come further  North…  Well that  is not correct either.

The problem is that strong northern branch of the jet stream cutting  across New England.  As long as that feature  is there and supplying the cold   air this Low pressure area cannot  possibly come UP the coast.  If anything  the Low will continue to get crushed and stay fairly flat and unorganized the cause of the strong polar jet over New England.

Now let’s be careful  with what I just said.    I did NOT  say the Low that comes off the North Carolina Virginia Coast cannot possibly come north the matter what.  What I said was that as long as that strong polar jet remains over  New England the Low cannot   come north.

My view is that we are going to see a system that will be struggling to hold together as it moves off the North Carolina were Virginia Coast.  It will bring some snow and ice to MD   se PA  s NJ     Northern DEL  and ice to rain over eastern  and central  VA.  It is possible that the northern half of the Shenandoah Valley could see pretty good ice event…  say from Charlottesville  North to Winchester and Martinsburg.


The operational European this afternoon as well as the European ensemble was  very bullish on the much colder pattern coming into the U.S.  However I have to  let you know that a LOT of energy meteorologist treated the European model with a tremendous amount of skepticism and disbelief.  The general view is that the pattern is going to turn colder for a 10 or 15 day  period …say from   FEB 5/6   to   FEB 15-19.  But that the cold is not going to be nearly as severe as some other meteorologists have been screaming about for the past two weeks.

That argument is based on the fact that the Polar Vortex that forms in North America stays over northeastern Quebec Canada and is not really far enough to the south or west to drive the arctic air into  the CONUS.     Indeed if you look at the day 10 European map at the 500 mb  you will see a a very deep intense and large    PV  in Eastern Canada.   And as you can see the   COLD air   pool around the   PV is equally impressive .  But  notice that the  deep blues  and purples are not coming south into the U.S.   as the   arctic  cold is   pretty  much trapped around the immense circulation of the Polar vortex.

In order to get this severe cold into some portion of the Great Lakes or New England in the second or third week of February …the PV has got to come  further south and west more towards the northern Great Lakes.  The current  position as forecasted by the  Day 10 operational European  or the   day 10  European  Ensemble is just not far enough to the south and west to drive true  arctic air into the U.S..

In other words its cold but it is not bitter cold and it is not severe cold.  If you like cold weather   then  FEB 2012  is going to be the  pretty  good.  The cold pattern could last for a couple weeks of February.  But it may be that some have been overselling this colder  pattern by a significant amount.

One last point before I  close.  Since January 29 I have been talking  about the possibility of a significant East Coast winter storm threat sometime around February 10-11-12.  I continue to see the potential  on the 0z and 12z  models …on the  GFS  and European operational models .. and on the  GFS and  European    ensemble mean  patterns.  It’s quite likely over the next few days that the GFS model in particular   will  LOSE  the  possible    southern Low….  By either crushing a completely in the cold a pattern or by losing the   southern feature.  My view is that the system for February   10-11-12 has far more serious potential then the  FEB 5-6   event .

Again this sort of confidence I have  for this  potential threat may seem to some of you to be a surprise or hard to figure given my reluctance to forecast the pattern change earlier in January.     But as I said many times once you know what sort of features   at  850  700    500    and 300 mb  mb   and what   those  maps  look  like for  big East coast snowstorms…   then the   favorable  pattern are  rather easy to detect several days out.    When the pattern is there  I am   there  and if the  potential is there  I can be rather positive about the chances if I think it’s warranted.   But if the pattern is not there I don’t give a hoot  in  hell  what  ANY weather model   is  depicting or  not   depicting — I won’t jump and I will be pessimistic .

My goal with East Coast snowstorm has always been to walk the line where you can see it coming and tell people it’s going to be big event several days out but not to oversell it or overhyped the event  just to get viewer clicks or readings .  My goal has been and will always be  here at when it comes to East Coast  snowstorms… that If I say  its   coming   it is…  And when I say it’s going
to be serious   it is.

Well that’s the goal anyway.

Santayana’s VODKA COLD

Posted by wxrisk | GENERAL,WINTER 2011-12 | Friday 27 January 2012 8:22 pm

1945  EST  27  JAN 2012… STARDATE  201201.27


Did you ever have one of those days where no matter how hard you try the one thing you wanna get to the just can’t seem to get to or complete? This is one of those days. I’ve been trying to complete this website update for 6 hours…since 2pm … and every time I attempt to finish it some useless human being others me or the phones I have to stop what I am doing …. or pick up someone. A very frustrating afternoon because there is a lot to say and I’m not going to take any prisoners in saying it and I don’t give a crap whose toes or feelings I hurt.

There are a lot of weather nuts  out there… ranging  the serious weather hobbyists    to it  lowest grade or lowest form:    the weather weenie.    If you are a winter weather lover like I am you always WANT  to get excited about the big snowstorms and the big cold pattern. Certainly I could produce a lot more business for my website and for the FACEBOOK  page by banging the    drum constantly about cold patterns which never show up.   But that is NOT what WXRISK.COM is all about.   As I  have stated many times before  ..  MY  inter forecast for Winter 2011-12   ( like most others) was disastrously wrong. This is the fifth time and I said that statement about my forecast in the past month yet many weather weenies out there seem to have this perception that I am suggesting my winter forecast was very good.

The point is that the last two winters have been very good for WXRISK.COM    . But the reason why I was bullish and aggressive with a cold and the snow winter patterns over the last two winters for the central and Eastern CONUS is because the patterns were.  I  wasn’t being Bullish on cold and snow to gain religious followers or to have snow nuts fall in love with me.

The purpose of practicing science and in particular the science of meteorology is to learn from the mistakes. My winter forecast was wrong and I have discovered –I believe– to be the synoptic reason why the pattern did not develop the way I thought it might. I stated those reasons in the last entry   GOTTERDAMMERUNG…

Strangely enough all this arguing back and forth has happened before.   Some recall that 10 years ago the winter of 2001-2 was also  forecasted to be a very cold and or snowy winter for much of the central and eastern CONUS. Back then WXRISK.COM was just starting out…  But I  got caught up in the consensus forecasting  thing and  went  for  a colder than normal and at least normal snow winter for the central and eastern CONUS   . Instead that winter turned out to be one of the warmest and least snow east on record!

I distinctly remember speaking on my new cell phone with other leading private meteorologists in various firms and energy companies. And the debate was going back and forth — there are no chat rooms back then– about how the NAO is going negative and that the whole pattern is eventually going to change.    ”VODKA cold”    was the term that everybody through around and used… Some use that term jokingly… some that term semi seriously and some very seriously.

And   the thing is   time after time the weather models constantly forecasted colder outbreaks of significant size and scale. And every few days of cold air patterns or outbreaks would be delayed until next week or 10 days some now.

Some of you may not remember but I am sure a lot of longtime whether hobbyists and fanatics and professional meteorologists do.    To be sure there were some cold days during that winter . But the massive pattern flipped or reversal that many forecasted or was hoping to occur … never happened .

WHY?      What can we learn about that winter    od 2001-02  which could tell us something about large scale patterns so that in the future when we see the same pattern we know not to fall for the same hype.

To a large degree  the  2001-02  Winter  Forecast  Busts  were caused  by    everyone looking at JUST  the  CPC  NAO   Indexes   or the EPO   or the AO.   But  NE or  Midwest snowstorms do NOT happen  because of the  Graph line from  a chart  from CPC.    For  Example    a Ridge or Block  over the  UK does  technically count as  “-NAO”  pattern but for    NE  US Snowstorms    having a  Ridge or Block  at 500 MB over the UK  is the Kiss of  death.

This first map is the 500 MB from December 14, 2001. Again I have highlighted the map so you can see the features I am talking about.

What you can quickly observe on this map is that the PV — polar vortex –is centered north of Alaska on the Asian side of the Arctic circle which is    EXACTLY   where the PV   stayed all  Winter back in 2001-02.

This next image is from the current winter and we can see two maps – 6 NOV 2011 and 7 JAN 2012. And clearly the overpowering feature on these maps is the persistent deep vortex centered over Alaska the Bering sea far eastern Siberia then or the east Asian side of the arctic circle.

Next here is the image from 19 January 2012…. And lo and behold what do we see ??? The enormous PV still centered over Alaska and the Bering sea!!. Its massive its deep and its huge and it’s blocking all the cold air on the wrong side of the world so that there is simply no sustained colder source in North America.

Over the past several days however there has been increasing signals from SOME weather Models of a massive historic pattern reversal with all sorts a severe arctic cold rapidly overrunning the entire eastern CONUS and all sorts of fabulous looking patterns that support snow storms.

Let me be clear about this.    Despite what you may have heard/ read  from other sources  that  may  be just trying to sell you  product and subscriptions… most of   drive for  Much colder / snowier  feb 2012  is being driven  by the GFS model. The European model   as well as  the GFS and the European ENSEMBLES are not nearly as bullish are not nearly as extreme as the operational GFS.

THE 12z GFS JAN 27….

Let’s take a look and see how and why the operational GFS has been showing this  and why  it probably will continue to be out to lunch for several days… and why the extreme solution of this model is unlikely to verify.

This image is the 120 hr 500 mb map… VALID for FEB1.   We can see that the NAO is strongly positive     ( note the closed 500 low OVER Greenland )      but we can also see north of Alaska on the top upper left of the map the age of the Polar vortex.   There is a shortwave or a piece of energy in the southern jet stream over New Mexico which is beginning to develop.

In this next image at 156 hrs OR FEB 2 … We see the northern branch beginning to merge with that system over the Mexico and a fairly deep trough trying to develop over the Eastern US     . But the arctic air hasNOT   yet reached the East Coast so the Low pressure area that develops over the SE coast ridge up the front produces rain across the Middle Atlantic states and into the big cities of Ide 95.     I got several emails today about the GFS forecasting a snowstorm on February 2 for the northeast… But as you can see the model data from the GFS does not show that at all.

This next image we can see the GFS at DAY8 or 192 hrs.   The   northern Jet stream has   continued to dig out  a   deep trough  that covers much of the Midwest and Deep South.     There appears to be some sort of  surface Low pressure area developing on or off the Southeast US. Coast..    And we have a nice looking 50/50 low off the Canadian maritime provinces.      But more importantly the model still shows the large polar vortex (PV) on the very top upper left of the map.

Remember folks that after 192 hours the model resolution of the GFS shifts or expands dramatically. The cause of this model truncation within the GFS… The model has developed a reputation for coming up with really wacky goofy solutions

We can see a good example of that at 240 hours.  For some reason the  GFS  at 240 hrs  has  grabbed the Polar vortex that was to the north of the northern side of Alaska and pulled it hundreds of miles for the south  in  a very short period of time— into southern Hudson’s Bay Canada.      This solution is well preposterous. It’s absurd.     The pattern is very impressive looking and nearly ideal or textbook for the development of a major East Coast winter storm. It’s just not likely to happen.

We see more of the same sort of crap at 300 hrs … By which time the model has completely lost it’s mind.    Do you really think the Polar vortex is going to be centered over Montreal Canada on February 8??? 


This solution is so extreme and so laughable that  the 12z GFS ensemble is totally against this solution. It keeps   the   heart of the Polar Vortex   STILL well to the north of Alaska on the Asian side of the Arctic circle and a secondary weaker extension of the vortex swing through Baffin island and northern Hudson’s bay and Labrador.



What the GFS ENSEMBLE is telling us is a fairly deep trough along the East Coast that will bring in some decent cold air for several days. But because there is nothing to lock the trough in position over the eastern U.S. it will slide off the coast and as it does so the NAO will turn strongly positive.

This next image is from January 7, 2002. And we see the large PV extending across the north slope of Alaska into far North Central Canada across the arctic region but not really moving into any portion of central and Eastern Canada.

At the time the weather models were developing a significant trough over the eastern U.S. And talked about the potential of a significant pattern change coming in the days after January 8 2002.

Amazingly enough this 500 map from 7 JAN 2002 is darn close to identical to what the 192 DAY 8 GFS model showed today.     The shape of the trough over the eastern U.S. back in 2002 is identical to what the data eight GFS model looks like. The attempt by the Polar vortex to move across Northern Canada 7 JAN 2002… Very similar to what the model is showing for next week. And just like back in 2002 in the first week in January were a lot of meteorologists fought that this was going to be the beginning of the big pattern change… we see the same sort of thing going on here in January 2012.




This FIRST image is actually from the early morning or 0z European model run of JAN 27 … VALID FEB 3 and FEB 7 . We can clearly see the model showing the huge massive Polar Vortex on the Asian side of the arctic circle and it is nowhere near the northern hemisphere.      Yes we do have a strong ridge on the West Coast and yes we do have a deep trough over the East Coast (+PNA) but the Arctic 0scillation (AO) is still VERY positive because it is very intense … It has lots of lines around it and it’s located over the arctic region.



There is a little extension or trough coming off the arctic oscillation moving through northeastern Canada at Day 10. Once that features swings eastward into Greenland at Day 11… the NAO turns strongly positive.

How was is different from anything we’ve seen so far this winter??    Except for the brief transitory trough over the eastern CONUS … It is the same pattern!

Here is the operational European from 12z JAN 27… DAY 10….valid JAN 27.     It seems to look to be a very promising and very winter like pattern developing. There’s a nice ridge      on the West Coast we appear to have some sort of block developing over East Central Canada which would be ideal… Cold air appears to be coming southward.


But again if we take a look at the European ensemble we see a very different story. The ensemble still keeps the huge vortex centered over Siberia and the Asian side of the arctic circle and that is just the wrong position to get sustained cold winter pattern over any portion of the central and eastern CONUS. It is strikingly similar to the problem we had in the winter of 2001-02…


Finally let me be absolutely clear about this.    The first week of February will probably feature some cold temperatures some of the cold air might be kind of impressive for a few days. As I said last update … I am not in any way ruling out the possibility of a significant snow for at least some portion of northeast U.S. And I have not EVER said ” no more cold “.

But I see nothing at the convince me that the pattern is going to change because just like in the Winter 2001-02 The PV remains in the wrong position and there vast majority of the model data keeps the Polar vortex in that position on the wrong side of the globe.



Posted by wxrisk | GENERAL,WINTER 2011-12 | Tuesday 24 January 2012 10:30 am

24 JAN 1030  EST     STARDATE    201201.24


There  is a famous scene and photograph from world war two where field Marshal Walter Model is talking to Hitler about the options left in the  Battle of the  Bulge   (a.k.a.   The Ardennes Offensive).  And in that conference   Model says to   Hitler…

” We must  face  the   facts   squarely  mein Furhrer …we   cannot force our way to the  Muese River. It is over”

That’s where  we  are right now.  Like the Ardennes Winter offensive of December 1944 …the cold weather or winter counteroffensive of 2012  is in serious trouble and is likely headed for total collapse and failure .    With the  Battle of the Bulge there are several important reasons for this–  the initial reaction of the American troops   along the   Our  River   and Elsenborn Ridge…  the inability to take   the key  town/ road junctions of  St Vith  until DEC 21  and  Bastogne which was  never  taken…  Just to name a few  reasons.

With regard to this particular winter   –or non winter depending on your point of view  –    the problems remain immense and the model depiction of how the pattern is going to evolve over the next 10 days has been really bad.    The   various    weather models  keep forecasting these sorts of significant developments of what the pattern is going to look several days down the road .   Yet  when that time  arrives and we compare the actual atmosphere to the forecast from six or eight days ago we see huge discrepancies .

Therefore if you are hoping  for…or anticipating a significant change in the overall pattern across North America and/ or the northern hemisphere which will bring about a stormy  and or colder  pattern for the eastern  CONUS…  well   you are in trouble.  It’s not going to happen . 

There  still remain  a decent possibility of a significant winter storm at some point in February or March for the eastern U.S. and especially the East Coast.  But in terms of a prolonged pattern    flip  or change?   NO. 

In the last discussion I wrote   (  BIG BERTHA   and the BUTT   SISTERS)     I tried to walk a fine line between optimism and reality.  There have been several false signals  given off by both the European and the GFS models during the past several weeks which seem to be indicating the pattern was about the  switch.  But I   also emphasized that despite repeated attempts by various models to accurately forecast  the AO and the NAO   to go negative….  In every case the models have turn out to be disastrously wrong.  Only twice since the beginning of autumn has  the AO and the  NAO  dropped into negative territory but that is not what we seen from the various weather models time after time after time over the past several weeks.


There is simply no other  way to say this.    The GFS  European and Canadian models…  Both with respect to the operational and  the ensemble  — have been  wrong.  As an extremely wrong.     As in  ” without a clue”.

Invariably   when  the models begin to see that things are not turning out as earlier forecasted they come up with a new solution after adjusting the pattern and delaying the cold.

For example  this image compares  the  European   Model / ensemble  from JAN 18  valid day 6…   to  TODAY  Jan 24.   

A quick glance would show that the day 6 European model has verified pretty well when compared to what the atmosphere actual looks like over the northern hemisphere today January 24.  But there is an important difference and that has to do with the key feature I talked about on January 18… which was the development of   New   Vortex over the Sea of Japan.  It was this feature on the  JAN18   European model at day6  that  was  suppose  to start  the entire pattern change.  However if we look at the current image  we see this   Vortex  is  NOT anywhere near the Sea of Japan…  It over the north side of Siberia almost in the arctic regions.

This has huge implications for the entire pattern.

Indeed  if we look at the   European model  ensemble   from JAN18   valid  at day 10…  And compare it to the    JAN  24   0z  European model for   JAN 28-29 … The differences are quite significant.

The   European  ensemble   at day  10  from  Jan 18… valid for the 28th …  Showed a very large powerful new vortex  centered  over the Sea of Japan.  The updated version of the European  model    valid for the 29th of January does NOT  show that  this feature at all!  There is   NO  deep close 500 low anywhere near the Sea of Japan ….so the entire pattern is fundamentally changed and the development of  the colder wintry pattern for North America does not exist.   Instead we have of new deep vortex over the north side of Alaska which is where is been for most of the winter and is the proverbial kiss of death for getting any sort of sustained cold winter patterns in the eastern half of the U.S.

Its Over.

Looking at day 10… valid FEB 3  …  We see more the same sort of thing.  The   PV  is centered over the western side of the arctic region barely reaching into the western hemisphere.  All the truly cold air is located on the Pacific side of the arctic circle not on the Canadian side.  This is simply the wrong location   for the PV  to be located IF you are trying to get the pattern to change over the eastern half of North America.


What a god awful nightmare…  If you like a winter weather in the eastern U.S.

Even if we try and project or hold for something to change down the road we  run into problems.  The general trend of the Arctic Oscillation   ( the  AO)  is moving back towards a neutral and is no longer dropping into the negative territory.   WHY?   Because the PV that was in the gulf Alaska and heelped  bring about the Seattle and Pacific Northwest snow and ice storm did  NOT move   east into western or Central Canada  ( like the Models    forecasted).     Instead it has reformed on the north side of Alaska where it  has  been for most of this winter…  which really is  + AO position.

Even the    negative trend in the NAO has halted and  the GFS  ensemble    show the NAO   levelling off at Neutral.     Again go back and reread what the model data and the trends are showing on January 18.     This was not   the way things supposed to be evolving .



And if you are a professional meteorologist and you cannot see this   then   you are  trying   to sell somebody something  or  you are  delusional.

And really  the pattern does not change much  no matter  what we look at with respect to any particular model.  For example here is the day 10 GFS  — the 0z run–   ensmeble mean.  We have a moderate sized trough in the east a little bit of a ridge  on the West Coast…  which  by the way  the European model does not have…  The dark purple areas clearly show  2  PVs  located on the Pacific side of the arctic circle .  Another words although really serious cold air is located on the long side of the world to get a sustained cold pattern to develop in North America


  *****     It is hard to understate how   damaging it is with respect to the pattern the evolving into  a  cold one over the eastern half of North America and the U.S.  with a huge vortex of centered over Alaska or snow on the western side of the arctic circle.  ****

If we look at say the  8-14 day   reforecast model from  ESRL …  The pink areas clearly show some sort of  -NAO   but the pronounced and very noticeable dark Blue  areas over Northern Alaska is  STILL   there and shows no signs of moving.  What this feature does is essentially cause the Pacific jet to become very strong…  And therefore  there   can be no  sort  of  pattern a amplification over the  eastern pacific / west coast of North America   ( NO +PNA  and distinct tendency to get a – PNA).


One last  note: if we do  in fact keep  and  hold   the -NAO   into   a good portion of   FEB … then  it still  might  be possible to  get  a surprise a snowstorm for the  northeast US  of the some magnitude.  By surprise I am talking about relative terms — inother words it might be something that 10 days out looks like nothing and then in the last 72 hours things change into a moderate or significant snowstorm for the northeast U.S.    In order get something like this to happen there would have to be some sort of pattern amplification occurring on the West Coast   – a ridge over    western US / Canada–   that would cause a  short wave to  dig much further to the south resulting in some sort a cyclogenesis over the southeast U.S.







Posted by wxrisk | GENERAL,WINTER 2011-12 | Wednesday 18 January 2012 11:31 pm

2330  EST  18 JAN   …. STARDATE   201201.18

I love forecasting snowstorms  in the Pacific Northwest.    It doesn’t happen very often  but   when it does  happen… is really quite interesting and very different from what we get in the northeast US.  Back in the winter of 2006-7  or  2007-8    a really great pattern set up for the Pacific Northwest around Christmas time and that  region  got   hammered with significant snow and ice storms –even  Christmas Day in Seattle and Portland and much of the northwest.  My experience over the past few decades has been that if you are not getting the Pacific Northwest right   –the West Coast and general but especially the Pacific Northwest– than the rest   of your  forecast is going to suck Moose  balls.

I am not going to spend a lot of time talking about the moderate snow event which is likely to move through portions of the upper Midwest the Great Lakes and the interior of the Northeast US  on JAN  20-21.  In fact if this was a regular winter this should be a pretty ordinary event and not get any intention are all.  Essentially what happens is that a wave of   Low pressure develops on the front as the large cold high over the north these slides off  the Maine  coast.  The Low tracks   into  WVA  then    through PA.  It’s a pretty weak system and a dozen have a lot of moisture with it and it’s moving pretty fast.  Still for the snow lovers  in the NE…  some snow for folks in the Northeast is better  than NO snow.
Now I know many of you in the eastern U.S. and especially in the northeast are probably shrieking or thinking    “Hey   DT  you  ignorant geek … who  Gives  a rat ass  about  the  the   Pacific Northwest?…”     If you are asking that question or thinking those thoughts…  then you’ve got a problem because you  are missing something really important about this particular snowstorm.    Not so much  about   the Pacific NW   snowstorm  per se… but  what is causing it …the implications for the entire pattern as  we  move into  February.  So pay attention there   sparky and let me tell you how Big Bertha  and her huge Butt plays into this whole thing .
By now I am sure  some of you have heard or read about the potential for significantly different pattern setting up  over  the next two weeks so that February and perhaps March 2012  end up being colder than normal or… at least  the threat or the possibility of it being colder  than normal over the eastern CONUS .    There are strong indications are  this MIGHT     happen but we have to be careful here.  We  have been  down this road a couple times before…  and every time we have gotten close or looks like the pattern is starting to change… it  turns to     Moose  Crap.    So if you have your snow boggles on and you all excited because somebody in Pennsylvania or in New England is telling you that this time it’s really really really gonna happen…  be careful.


A word to the wise.  Saying the same thing over and over and over again… or in this case forecasting the pattern change the pattern change the pattern change…  only to see the pattern finally change…  is not REALLY  forecasting weather.   What you are doing is saying the same bullshit  over and over  and over.   In other words if your  forecasting skills in the extended and long range   have been really good  in the last two winters…  But now you seem to have trouble figure out was going to happen and when / IF the pattern change is going to occur…    that  is  probably a clue  you are  doing something wrong.
This first image shows us the long  terms trends  of the NAO and the AO since September. 

 As you can see from the image it is readily apparent  that the NAO and AO have only drop into the negative territory twice since the up SEPT 15 !!!    But more importantly since December there had been a several tries or surges where both the  NAO and the AO have reached the Neutral Line  — which I have  Number as  you can see.   And every case the model data showing the AO or the NAO   would  drop to  negative territory but in every instance  -  EVERY    INSTANCE–      both the  AO and the NAO bounced back up strongly into positive territory and all of the model data turned out to be disastrously wrong.      So again if you’re absolutely certain that the pattern to  turn around  and that it is  going to  turn out  to be a great February and March 2012… BE  CAREFUL.  The trend here is not your friend.  Of course that’s not to say the trend can not be broken but it does need to be respected .



This next image shows the overall pattern back on January 15.   As you can see from the image itself I’ve highlighted the massive explosion in the WPO  as a turn negative and built a huge rage into the Bering sea….  and Alaska…  that expanded all the way into the western and Asian  side of the Arctic circle.   This  explosiove   Ridge developemnt  was caused primarily by the stratospheric warming event.  Also keep in mind that when the models of first detected this development   –  back in late DEC and  early JAN– most of them showed this would lead to a much colder middle and the latter January…  Which as we  all now know…  did NOT  happen.    Instead… the huge Ridge in the Bering sea and the western side of the Arctic circle moved into eastern Siberia.    This in turn allow the polar vortex to move into western Canada and eventually into the Gulf Alaska were it is currently  situated.  It was this very movement of the  PV which is  WHY the arctic air came pouring over the Rockies in the continental divide into the Pacific Northwest and the Seattle Portland metro areas!!!   


But more importantly is how the pattern slowly evolves.  This next image shows the  72  hr — 12z  JAN 18  run-   valid  JAN 21.  I  have highlighted the individual disturbances or impulses and Pacific jet stream and you can clearly see the amazingly cold bitter arctic air mass over Northern Canada  that is associated with this  super   positive  AO.    This is one of the reasons why having such a strongly positive arctic oscillation is so bad for those wanting winter storms over the central or eastern CONUS.  As you look at this image    you can  clearly see   that  in this sort of  flow there  is very little way to get that cold air to come southward .

We can see a new development which is a  core  or center of the  PV reemerging or developing over anchorage or in the Gulf of Alaska.  Meanwhile more strong impulse is a batter the West Coast move across the Rockies into the planes bringing in much milder air


120 HR  ECMWF   VALID   JAN 23…  In this image I have highlighted the upper air map at 500 MB  and the  SURFACE map.  The piece of energy in the central Plains   develops into a significant winter storm for the Great Lakes which pulls up a lot of warm air into the northeast U.S.  Chicago   COULD have another  significant snowstorm however.   More importantly however it is this buildup of warm air along the East Coast which is driven northward into the high latitudes and forces the Heights to rapidly warm or increase over Eastern Canada.  Sometimes is buildup of warm air and increasing Heights can cause the NAO   to flip especially when it’s followed by several surges of warm air from the eastern U.S. into  eastern and southeastern Canada.

That is exactly what happens over the JAN  24-25-26   time frame.

This  image is a hemispheric shot of the European model at   DAY 6 .. JAN 24 .  I  have highlighted some important features which are occurring at this time over the hemisphere.  The most important  is  feature  #1 which shows a another Ridge exploding northward into the arctic regions from the northern Pacific however this is significantly different than what we saw back on January 14-15.  That ridge   exploded northward over the Bering sea and we did not have a PV  (Polar Vortex)   in the gulf Alaska  which will  likely have   JAN 24-25.     This  Ridge develops over eastern Siberia…  because of the new vortex which forms over the Sea of Japan.  The development of a deep vortex / 500 Low  in the Sea of Japan is  text book teleconnection for a much colder pattern over the eastern U.S.    


   ASSUMING   this is correct   the Ridge in Eastern   Siberia will begin to drive the  PV in the gulf Alaska…  to the   east into Western Canada which begins to alter the entire pattern.

At Day 7  JAN 25…  The Great Lakes Low is now over southeastern Canada but it’s still feeding up warm air into southeastern Canada.  However right behind that we see a major trough amplification over the entire Plains  and the Midwest   ( see  THICK  BLACK Line).  This forces another surge of very warm air into the East Coast.    Meanwhile over the West Coast and the eastern  north Pacific   the  Gulf of Alaska  PV is being driven east   while a  ridge is beginning to form off the California Coast.

DAY 8 …    Again I have  matched up  the upper air map at 500 Mb with the surface  map   so YOU  can follow how things develop.  The new  trough over the Mississippi Valley has caused   a surface Low to form over Alabama…  while warm air surges from the Deep south all the way into the Northeast U.S.     Again I cannot stress how important this warm areas with respect to feeding the developing  or  Building   500 Mb heights over  eastern  Canada …  Which in turn brings about the face change in the   NAO.  So even though I know winter weather lovers in the eastern U.S.  will hate these warm temperatures the two serve a purpose! 

In this next image DAY 9 …  We can compare the European vs. the GFS from a hemispheric perspective.  Both models or a remarkably good agreement as  they  BOTH  show the PV in the gulf Alaska…  They both show some sort of Ridge trying to form off the Southern California Coast in the eastern Pacific…  And they both show some sort of building or increasing Heights over Eastern Canada.

By DAY 10   –lets  use the   EURO ENSEMBLE 500 mb maps – the changes are underway big time.  Big Bertha has now left the gulf Alaska…  or rather is leaving the gulf Alaska and sliding into Canada.  It’s doing so because of the developing ridge  over the Bering sea and eastern Siberia.  In addition the Heights are rising rapidly over Eastern Canada and southern Greenland which indicates the possible development of a -NAO.

The 12z GFS  ensemble – JAN 18 run — strongly agrees with this overall development of the pattern.  In this image we can see the 6-10 day    500 MB  height  CHANGES.  This is useful in showing us where things are trending..  We can see a very strong negative anomaly over the gulf Alaska  which is the strong Polar Vortex.         But we can also see the Heights beginning to increase over Eastern Canada.

Looking at the same product but now for the 11 to 15 day…  We see major changes.  The GFS  ensemble shows the vortex that was in the gulf Alaska  has now shifted east into western or  Central Canada.  The Heights are rapidly building in the Gulf of Alaska and we see increasing Heights over Greenland as part of a  -NAO.

If we look at the  12z GFS  ensemble itself   — the 500 mb  mean –  at   DAY10…  We can see a very close match to what the European ensemble model is showing.  Note the strong vortex over the Sea of Japan!     Note the    ridge over   far eastern  Siberia and the Aleutian islands…  And notice the  dark purple the long date and shading extending from North Central Canada down  to NW Ontario Canada.  This tells me that the model is showing the  PV is splitting apart or redeveloping.

312  HR  the 12z   GFS  Ensemble has evolve into a completely different and full blown winter pattern over the north American continent.  As I have highlighted here…  There is a new deep  PV  over the Sea of Japan…  A very strong Ridge e over the Bering sea and  new PV   with 2 centers: one over  far N  central  Canada  and the  otther over  James bay .  If we accept this model as verbatim or being fairly close to the truth…  We now have a raging +PNA  pattern  a   – AO   a  – NAO and the eastern U.S. is now in business for February winter storms.


This is probably the most important part of the whole discussion given what’s happened this winter.  There are so many things that could go wrong with this sequence of events as shown by the weather models.  But it’s important to do this because you don’t want  get caught up in the mental loop  or  trap of believing that the pattern change HAS  to occur because the weather models say it has to occur.

1) the development of the deep   500 Low that becomes a new polar vortex feature in the Sea of Japan.  If this feature does not develop   THEN the entire pattern change will fall into a pile of  Moose    crap.      It is this feature which causes the Ridge to develop over eastern Siberia and the Bering sea.  If there is no big  500  mb Low  in the sea Japan in the last few days of January then   the ridge  will act  TOTALLY different…  And it will not cause the changes to occur across North America.

2)  this is related to  #1  above.   Suppose the   PV in the Gulf of Alaska it does not move.  Say goodbye to the pattern change.

3)  THE  WARMTH  over the   eastern  US does NOT   reach into   eastern  Canada …  Which in turn would mean a much weaker  -NAO.  Or it might only force the NAO   to go to briefly neutral…  which as I stated at the beginning of this essay  has been the trend all winter long.






Posted by wxrisk | GENERAL,WINTER 2011-12 | Thursday 12 January 2012 3:07 pm

1500  EST  JAN 21   JAN 2010….   STARDATE  201201.12


There is really no other way to say this other then coming out and saying it.    My forecast– my scenario about how the second half the winter was going to evolve –is probably not going to be correct.    I am not going to come out here and tell you that I am going to get the overall 500 MB pattern correct like  whats his name does over at wxbutt .  Wrong is wrong.  I am very likely going to end up being quite wrong with regard to the second half of the winter and how things are going to develop.    There is no point in trying to a blow smoke in your face then tell you the air is clear.  One of the things I have learned from dealing with energy and grain traders over the years is that most of them can handle the idea that your seasonal or monthly forecast is going to turn out to be significantly different or the pattern change you have been forecasting is not going to work out sometimes.    What they don’t like is when someone tries to tell them that Up is Down or that Mild is Cold.   My experience has been that when you do that you will end up losing clients faster than Newt Gingrich’s popularity at a club for growth meeting.


What IS important when something like this happens is to figure out what you did wrong and lessons that that can be learned and absorbed for another day and another time.    Over the next 10 days the actual forecast looks pretty easy. First the strong arctic cold front comes through tomorrow…. There may be a clipper low which brings WVA VA NC MD some snow showers on the 15th…. A brief warm up the headm ahead of the next cold front on the 16th and 17th … Followed by another strong arctic front on thr 18th to the 20th.

What I am talking about here is how I anticipated the next 45 to 60 days to develop.    Now some are you are probably already saying    ”hey DT you crazy ignorant bastard… Maybe you are jumping the gun to early and giving up hope. Maybe the pattern will evolve as you thought earlier into it more bullish colder wintry pattern for the central and eastern Conus…”

Maybe. But that is not the way things works with me.

Look… If the pattern ends up turning colder and February and March but in a manner that differs significantly from what I have been talking about over the past 10 days…. It is unethical of me too suddenly assert Hey look at me I got it right after all”.       I dont   DO bullshit.

I don’t mind talking about my successes and I don’t mind talking about my failures.    One of the things that you will find here at WXRISK.COM is that I do both with equal intensity and focus. No matter how good you are … no matter how much on a roll you may be… You will eventually end up being wrong an disastrously wrong.    If you are afraid of being wrong stop forecasting weather and go sell shoes.

When I use to post over at easternus wx then over at American wx one of the issues I’d try to stress is that not all SSW  ( sudden stratospheric warming events)    are the same and they don’t always mean that the pattern is suddenly going to turn significantly colder and or snowier for the central and eastern CONUS.      Sure there is a tendency is that the happened but the correlation is not that strong.   A few years ago there was a pretty strong SSW event– I think it was in winter of 2005-6 — and there was a lot of gleeful anticipation that the SSW event would lead to a turn to a much colder and wintry pattern for the central and eastern CONUS. It did not.     To be sure the pattern DID change but NOT in a way that made a difference for actual weather conditions east of the Mississippi River.   I could make the argument here that the pattern is changing if one looks at the overall large scale features over the northern hemisphere.

But that’s just a disingenuous bull shit argument… and like I said I dont DO bullshit.

When I made the last post back on Jan 9….    I presented this map showing how the SSW –sudden stratospheric warming– was going to cause the jet stream to develop  a  massive Ridge over the northern Pacific that would expand through the Bering sea into eastern Siberia and Western Alaska… and reaching into the Arctic regions.

But at the time I also stated quite clearly that this sort   of  pattern development  is not a great pattern for the Midwest and East coast:    the development of the 500 MB ridge ( aka the -WPO)    that pushes into the arctic region often causes a equally strong negative 500 mb anomaly   (  A TROUGH!!)   — to form over western or southwestern Canada and Pacific Northwest  …. which is    really  a -PNA  .    My entire argument or forecast for the second half of the winter was premised on the idea that the RIDGE over the Bering sea would continue to drive into the arctic circle ( where it would becomne a Block) moving over or close to the north pole regions and expanding into northern Greenland. This in turn would force the NAO to move from very positive to Neutral to Negative and the combination of both of these features — the Block over the arctic regions and the developing positive 500 mb heights over Greenland– would force the entire Polar Vortex out of the arctic regions ( +AO) south into central Canada (-AO). Well that’s what I was thinking anyway.

However in the last update I also listed  under     the   “WHAT COULD WRONG”   department … that the developing Ridge over the Bering sea   might retrograde
( move west)    back into eastern Siberia…. and that such a  development    would of course destroyed my entire scenario.


It’s pretty clear from the last several model runs that yes the Bering Sea Ridge   IS  going  separate itself from the main flow   and will  become a block over the western arctic regions. But it  is also quite clear that this  Block  IS  going to move WEST  – not   east  or  Northeast —  west and that this retrogression is going to allow for deep trough / closed 500 mb Low to form in the gulf Alaska in the mean pattern.

Oddly enough the development of deep closed 500 mb Low in the gulf Alaska is identical to what we have been experiencing since the last week of November NOV.    So yes we probably will end up back were  started by the time we reach the last week of January.     Indeed the last few runs of the CF2v2.0 in week 3 and 4 … which had been showing a fairly cold pattern developing now shows a very mild and to January east the Mississippi River.

What  is really interesting is that when the pattern turn into CRAP back  in  mid and late  November it did so because of the development of a large 500 mb Low over eastern Siberia.    This feature was very prominent all maps and I talked about it    often   during NOV 10-DEC 15 period.   Having   big a deep closed 500 MB Low over Siberia is not in itself     the kiss of death per se.    BUT… there was also a large positive 500 MB height anomaly– a FLAT ridge– over the central portions of the North Pacific   and that   made things much worse.

The proximity of these two features fairly close to each other ensure that the Pacific jet velocities at 200 mb and 300 mb would be extremely strong    (at times reaching 200 knots)    and therefore would not be allowed to buckle or amplify.   Very strong jet streams like this are impossible to get to “buckle” or amplify and without that you can’t get a ridge on the West coast of North America.    This time around the stratospheric warming event caused a major amplification of the pattern… over Bering Sea and eastern Siberia!!!    In other words the EXACT same location on the globe. T   he fact that these two events 60 days apart developed in almost exact same location on the globe can not be a coincidence.

Some have speculated that the development of excessively deep heavy snow cover over eastern Siberia in combination with the Asian mountain Torque is the driving force here behind the repeating pattern. But that is a discussion for another day.  Besides if I get into that is gonna end of sound like a bunch of BS…

And like I said… I dont DO bullshit. Wrong is wrong…I am going to be wrong.

The only give saving grace here is that in this new pattern the temperature contrast between say Minneapolis and St. Louis…. between Boston and Richmond Virginia… could at times the quite extreme. I am not yet prepared to completely kill off the entire winter but I would not surprise me at all if this winter ends up being very close to 2001-02 or 1972-73.


Posted by wxrisk | GENERAL,WINTER 2011-12 | Monday 9 January 2012 8:15 am

0800  EST   9 JAN  2011… STARDATE   201201.9


The 6z the operational GFS this morning is developing some sort of coastal storm just after  day 10  for the Northeast US.  The model does not show a huge event but it definitely shows a secondary Low  developing in the arctic air and bringing a moderate to significant snowfall for the northeast U.S.  Mostly to the north a Washington, DC Baltimore area.

I do  NOT   like that solution for number   of  reasons and those reasons actually end up supporting the solution I talked about  over at   HARDCORE–JAN 7post.   To begin with the 6z GFS  ensemble  does NOT   support  the  6z operational GFS .  But more importantly with the GFS to showing is the development of a deep trough over the eastern U.S   day 9-10  as opposed to a broad U shaped trough  from the  European  AND  GFS  ensembles.

In addition  the GFS  develops this  deep  eastern  US trough  by forcing the NAO  to shift for more rapidly into a negative phase .  And that solution if you look at the overall pattern makes no sense.  Eventually I do believe the  NAO  is going to go negative   BUT   as long as the huge  Polar  Vortex  / +AO is still up across northern hudson’s bay and Baffin island …  That was features a large circulation will still keep Heights way below normal over Greenland …  Which of course precludes  a -NAO   development by day 9/ 10 .

Indeed if we take a look at the European model  and european Ensemble…  we see a much more reasonable solution especially given the persistent strength of the Pacific jet stream which has been a major aspect of this winter since the middle of November so far.      The operational European shows the huge block which is developing from the Bering  Sea  into the western half of the arctic region  ( called a  -WPO   by meteorologists and  Climatologists) .  That in turn is forcing  the PV / +AO  slowly southward  and   THAT movement of the  +AO  in turn is forcing the arctic air south in all directions… SOUTHWEST  …  DUE SOUTH  and  SOUTHEAST.    And THAT in turnn is forcing the   STJ  to the south as well.


This movement an overall solution to the pattern is strongly supported by  the  European ensemble


AND   GFS ensembles…  which all show the  same  sort of thing     day 8-9-10.



Posted by wxrisk | GENERAL | Sunday 8 January 2012 1:21 am

0130  JAN   8  2011…. STARDATE  201201.8

It is 1:00 AM and I probably should not be doing this but after   looking at the latest data this evening I am so excited about the upcoming pattern change that I actually cant  sleep.    I am reminded of the U2 song      Something is about to give… I can feel it coming… and I think I know   what it means…


The problem is I don’t know how to begin to describe this pattern  change.  On the one hand I don’t wanna go   ballistic and sound like I am  freaking out…  But on the other hand it’s hard to look at this stuff and  NOT  salivate .    The  POTENTIAL   for the upcoming pattern flip to be historic in  terms of the reversal of what we have seen so far is pretty darn impressive.

Even though the pattern remains quite warm across  of most of the U.S.  there   are major changes under way.  This is   the current hemispheric jet stream map   at 500 MB   JAN 7….  and we can see three distinct ready areas which represent   positive height anomalies or ridges  which are building.  The first one is over  the West Coast  of North America.  The second one is over Central Russia of which is building in towards the Asian side of the arctic circle…  And the  third one is building over the the Azores the northeast and Atlantic and in  towards the UK.

The large and powerful rain storm which is likely to hit much of the eastern U.S. in some form or another on JAN 10-11…  will probably be the  beginning of the event and set off the pattern change.    Once this Low  moves through the northeast US and into southeastern Canada there will be a  large scale arctic outbreak  JAN  12-15 across all of the CONUS east of the  Mississippi River.  This outbreak has been showing up with the model for several  days and is well handled by most of the medium range models.  However is a lot  more to this   than   just     this  arctic air mass outbreak…  which will be  reinforced by a second  cold front   JAN 15 .

This next image shows the overall pattern  at  Day 9- JAN 16.  The map of  the left hand side is the European the map and the right hand side is the GFS.   The models do not agree on what   is going  happen over the eastern US– the  European as a deeper trough  ( dark blue shading)   whereas the GFS   shows a   zonal flow.  The model disagree because the European has a    Low off the Pacific Northwest coast… which in turn shows a bit of are Ridge  over  southwestern Canada… which in turn   allows the  model  to  orm that trough  over the eastern US.


However that’s not what’s really important here.  The key thing here is to  look at what happens over Alaska and the Bering sea as well as Scandinavia/ Northern Europe.

Both model show a rapid explosion in positive height anomalies at 500 MB over the the Bering sea Alaska and far eastern Siberia.  In other words there  is a strong Ridge  which  is building in the jet stream  and  rapidly expanding into the arctic region .  This feature is called the  the negative phase of the  WPO- — western Pacific oscillation.  For most of the winter we been in a  strongly positive phase   of the WPO….  which is featured a large   500 Low over Alaska and the Bering sea.

The massive warming which is occurring at the stratospheric level –  SSW– is causing the entire western Pacific oscillation to reverse phase and  alignment.

In the classic case of the -WPO/-EPO  pattern which you can see here…  The development of a huge ridge over the Bering sea and Alaska is not a great pattern for  the Northeast quadrant of the country…  But it’s a pretty good winter storm pattern  for the Pacific Northwest…  Most of the Rockies…  the central & upper Plains the Great Lakes and  sometimes   New England.


In the  -WPO/-EPO  pattern the mean trough position is centered   over southwestern Canada and there  is often a large upper Low which develops over the Pacific Northwest / southwest Canada.  The arctic air comes pouring southward…  sometimes over the continental divide and the Pacific Northwest will suddenly turn bitterly cold and it could even be snowstorms in places such
as Portland and Seattle   right  on the coast .!!  ( see early  FEB 1989 and  DEC 2008) .

All other things being equal this pattern will often results in a flat Ridge existing over the southeastern U.S.  which allows much of the Deep South into the Middle Atlantic states to run either seasonal temperatures or mild temperatures and that means storm track is to the north along the Jet stream.     This  because    the    trough over the   western  or sw  Canada into the   Pacific NW still counts  as   -PNA


However there are exceptions to this.  There have been cases where the expansion of the ridge in the  Bering sea / far eastern Siberia and Western Alaska becomes so strong as it pushes into the arctic regions that the  deep 500 Low over Greenland  — the  super  +NAO  — it’s forced east away from Greenland it into Scandinavia.   At the very least such a movement would cause the  NAO  to  move from  strongly positive to neutral.   But as the   -WPO   ridge continues to expand into the arctic regions…    two things  can  and  do result .

FIRST   the    500 Mb heights over  Greenland begin to rise and move into  the positive anomaly stage which is the beginning of a   -NAO / Greenland ridge.  SECOND the super intense Polar Vortex …. aka   the super intense  +AO  (arctic oscillation)  is forced southward .   The   +AO heads  increasingly  further   and  further south in to  Hudson’s Bay.  This in turn forces   arctic air to spread south and east in all directions … across the  US  Canada border from the Pacific Northwest into New England.  The   further south the AO   moves  the colder and gets and the further south the arctic air drives  into  the CONUS .


In addition of course this movement of the  AO south forces the entire Jetstream pattern southward….  So even though we do not have a Ridge  on the West Coast per se  and the  PNA is still technically   negative  the pattern becomes  one that features below and much below normal temperatures over 80% of  the CONUS  and a very active and engaging winter storm track.


Of course this is a somewhat unusual scenario but not unprecedented.  True     this sort of  development in the   pattern  does not happen very often   but  the  massive stratospheric warming is of course helping this entire pattern develop as I’ve described above and we can see that  by taking a look at the CPC    super  ensemble  day 11  map .  Notice the large areas of red with lots of con tours around which had built across the Bering sea and eastern Siberia…  all the way into Greenland   by JAN 18.

The  + AO  is clearly being force    towards Hudson’s bay and deeper towards the U.S. Canada border.  Indeed this is exactly what the day 10 European  Ensemble is showing as well.  Notice here that the  AO  which has been over the  arctic circle for most of the winter is now south of the arctic circle over Baffin island and approaching the far northern portions of Hudson’s bay.

In  severe cases sometimes we even see a linkage between the -WPO  and the   -NAO o ver the arctic region.  The last time this happened  was in the severe cold winter Nov 15-  dec  31  of 1989.  This winter featured the second coldest  DEC   ever  on record for the entire United States and featured a historic blizzard for Eastern North Carolina Iin late  DEC.

All that being said let me be clear here…  I am not in any way forecasting a historically severe prolonged six week period of extreme cold…  At least not yet.  Nor my forecasting a historic snowstorm for Eastern North Carolina.  But as we can now will clearly see the stratospheric warming is real    it IS  impacting the entire pattern and things are rapidly changing.  We  are going to see the entire AO get forced southward but the only question is how  far to the south.

The 0z JAN 18   EURO  shows the trend nicely…

of course  there are   STILL lot of things  that can  go  WRONG  here…   for example   IF   the  -WPO  decides to slide  back  WEST into    central Siberia  that could be    problem.  If the NAO  goes  Neutral    and does NOT  go  negative…   THAT would also  lead to a different  result.


Posted by wxrisk | GENERAL,WINTER 2011-12 | Wednesday 4 January 2012 12:52 am

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.