*** BIG EAST LOW OCT 28 -29 ***

Posted by wxrisk | GENERAL,WINTER 2011-12 | Friday 28 October 2011 6:15 pm

1815    EDT      28      OCTOBER

 

 

 

 

  

 

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1700  EDT    OCT  22

While we  have had a few significant eastern U.S. Low  pressure areas… so far in this cool season so far we have not  yet   seen a MAJOR      East coast   or  eastern US   Low.  The data is increasingly showing that that is likely to change as we approach the end of the month with the potential for significant East Coast Low pressure area on October 28-29.    Depending on the track and how the system develops the potential exists for significant early season snowfall over the mountains of  eastern TN   e  KY of good portion WVA …  southeast OH ..far western MD…  western and  central NY  state …  western and central PA  far western MD.  There could also be some snowfall occurring in the Pocono Mts of northeast PA …  as well as the Catskills  in   eastern NY and the berkshires in  western Mass.

Even though I shouldn’t have to say it …. let  me  be clear…  This  event…  even  in the cold est and  worst case scenario…  is NOT a threat for any sort of snowfall over any portion of the I –   95 big cities  from RIC  to BOS.     There may be some other folks were talking about that–   but you won’t hear it from me.

We will start out by look of the 0Z   Saturday 10/22   run of morning European model.  As you can see the model has a pretty strong low pressure area centered for close to Baltimore Washington, DC on the western side of the Chesapeake Bay.

 The  three  images of the 0z  euro   show   regional impact of the  major coastal Low late Friday night in deciding morning over the Middle Atlantic states and over New England.

    

I  have highlighted  or  drew  in the rain snow line which you can see is mostly over the mountains  of  WVA   western MD   and  PA.

In these next images you can see how the European models developing this major East Coast low.  Essentially  there are  2  pieces of energy  — called short  waves  in the wx Biz   that cause  this coastal Low  to develop.   Th   1st one is over  NM     ( the southern  short wave)   and the northern s/w   over the   Upper Plains  / MN.    What is important to notice here is that the tilt or alignment  of the   2   pieces of energy  or short waves  is   SW  to NE .     This sort of angle or tilt is referred to   as a   “positive tilt”.    Over the next two days  the  0z   European model  at day 5  and day 6 slowly swing  these two   short waves around  so that by the time they reach the Mississippi river /  Delta  the southern  energy is   now  NEUTRALLY tilted… that is running S  to N.  The Northern  energy is dropping into the southern Energy which is a process referred to as PHASING  in the weather business.    Whenever you have the two jet streams of phasing like this and the merging of two piece of energy  it is always a sign that a major Low  is  going to form .

The  0z 10/22 British  Model– the UKMET  — strongly supports the European scenario.  It shows the same sort of phasing or merging of the two pieces of energy over the Southern Mississippi River at Day 6.

Not surprisingly,… the 0z and 12z   GFS  model  runs  have  a totally different solution with regard to the development   of this potential system  for OCT 28-29.   Both   model runs  of the GFS    show  this MAJOR Low   but the model develops the system much faster because it handles the upper atmosphere synoptic  pattern Much differently.   And because the Low  forms much faster …  the  track is  waaaaaay inland.
This image from the 0z 10/22  GFS shows  the Jet stream (500 MB)   valid for  8pm on  10/28.


The 0Z GFS  model  has a  closed  off DEEP Low over    the Deep South  that has  developed a  NEGATIVE TILT…    this is where   the tilt  or alignment   of the    Upper Low is running    NW to SE.    The  12z 10/22  run of  GFS   continues    to do this.  This sort of   RAPID  phasing  between the  Jet stream is known   ” bias” of the GFS Model.

These images — from the 12z  GFS  run –show  how fast the  model is  swinging around the  southern s/w  froma  POSITIVE  to NEUTRAL   to  NEGATIVE tilt.  A  Classic case of the GFS  Model over phasing . 

     

 

On the other hand the 12z saturday   EURO  model has come  out   and seems to have  backed off the  BIG east coast Low idea.

 These two images show the     JET stream (500mb) maps and the surface maps at  day 5 and  Day 6.  We can clearly  see the southern energy over  NM  and the northern energy over the   Upper Plains  at DAY 5…… but at Day 6   the  model seems  to have totally  lost southern energy!

Remember it is the PHASING  of the  two  pieces of energy that causes the Big East coast Low.   If the southern energy  is gone  there  is NO phase and NO big storm.

 

Indeed that is  EXACTLY  what the    12z European Model  at day 6 shows ..an ordianry   Low over the  northeast US. 

 I am  not altering  my forecast at all .  I think the 12z GFS and 12z  EURO Models  are   both wrong .

WINTER PATTERN 2011-12

Posted by wxrisk | GENERAL,WINTER 2011-12 | Sunday 23 October 2011 9:32 am

Welcome to WINTER    2011-12   BLOG…   on this page of the   WXRISK  I will be  discussing    various aspects  of   the upcoming   winter.   The focus  will be on  …well everything winter  related.  Not  Just  My   winter forecast   but I will discuss     “OTHER “   forecasts  and     ideas  that are   ” out   there”  … as well as   the   developeing La Nina… the  QBO…   the snowfall   build up  in Siberia  … the  -PDO      and the overall  synoptic patterns.   The  focus will be   MOSTLY  on the   CONUS  but    canada will get a LOT of mention as will    Europe  and the Northern Pacific. 

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22 OCT   2300 EDT

 The NEW  data has come from the folks at RUTGERS …. finally.. and over te last 2  weeks …week 40 and week 41 … there  were  MAJOR increases in the snow cover  over in  Eurasia/ Siberia.    I   forecasted and posted about  this   major  Low and   widespread heavy snow event   that was likely to occurr  in the   section  below  ( 17  OCT).  This    increase certainly  did NOT   catch  me   by  surprise.     The current  value of  16.66  is  the  13th  SNOWIEST  week 41  snow   in the last 34  years.      Consider    the list  of  Snowier week 41  from the past :    2009… 2006 … 2002…  1998…  1977… 1976…  1972… 1971… 1970… 1968… 1967… 1966  .    All but one of those  years   were  great  Winters …

 These  next 2 images   show the same  sort of thing… snow  cover build up   in  Canada  from OCT 22-29.

17 OCT   2020  HRS

 
In this first image we can take a look of the snow cover across northern hemisphere as of October 16.  And we can compare to what we saw this time last year and the differences are fairly strong  especially over North America.

 

Right now the snowfall cover in Northern Canada is a bit more extensive than was this time last year.  The difference is not huge but it’s definitely there.   In addition the massive snowstorm which is still going on across eastern Siberia has dropped widespread significant snow across much that region.  This major increase in snow full total coverage will probably not register on many of the indexes  for  northern hemisphere snow cover until next week.

Next week are beginning to see some signs of a pattern change developing as we approach the end of the month. The day 10  operational European  as well as the European  ensemble   are showing the development of a fairly strong   Low    southern of Greenland   at day 9-10 …which alters the entire wavelength of the pattern and allows a strong raging over Scandinavia to  retrograde    North and west into Iceland and eastern Greenland .  It’s too early to know for certain whether not this  this development in the pattern over the northern hemisphere is   a model fantasy  or of  we are seeing the signs of the   things beginning to change.  But is the first time this autumn we seen this sort of development.

 

   

 

12 OCT  1300 EDT

in order see the importance of the snowfall cover with regard to development of the winter pattern across North America  it’s imperative  that you have read the winter forecast for 2011-12.  Whether not you happen to agree with the forecast is not really the issue but the research by Dr.  Judan Cohen is  IMO overwhelming and very significant. 

  For the past several days of the tracking the pattern in Asia and especially if regard to Eastern Asia and Siberia with the development of significant snowfall.  I have   been doing this   — watching  SNOWFALL patterns and  build up over  Siberia and Northern Canada — for number of years.   (I do   this  mainly because  there  is not much else to do October outside of tracking the baseball playoffs. )

 The   large  scale or  synoptic Models  –   the  ECMWF  the    CMC    and the GFS  — have AL  have   been showing a    massive intense 500 Mb Low    coming out of  Finland… tracking through  northwest Russia …  over the northern   Urals  and   across north   central   Russia.  This Low  drops  southeast   this  weekend  and develops  a SEVERE    negative tilt    over far   eatsern Siberia.  By OCT 17 the European and the GFS models developed they keep closed  massive  500 Low over the  sea of Okhotsk  between sSakhalin  Island and the Kamchatka Peninsula.

The operational GFS   and the  ECMWF    both show  a  massive    Low… at 972 MB   located over the northern  Sea of  Okhotsk.      This is a very large and powerful system not something you typically see this early in the season and it drops a tremendous amount of snow.

This next image shows you the snowfall  FORECAST   TOTALS   coming from Eastern Asia.   Of course this is the GFS model… thru  day 8…    BUT it is  at the  HIGHER  resolution   And  as I showed above ….  it is closely aligned and supported by the European.     As you can see there is a massive increase in snow full coverage  that occurs over the next eight days the cause of this powerful early winter like massive Low.  Over the next several days of the tracking the system to see if the models change significantly.


Closer to home…  The development of a massive   trough over the eastern CONUS in the period   of OCT 18-19-20 is very significant for numbered as reasons.  First   this    troiugh  and  Low   development   would be fourth or fifth  significant Low  since  Sept 1…     If we can keep this persistent wrath over the eastern U.S.  It has significant implications for the overall pattern with regard to the winter of  2011-12.  
The initial area of developing and fairly strong  LOW pressure will bring significant rain to the upper Mississippi Valley in the Great Lakes on   the 18th.   But the trough in the Jet stream will continue to amplify   becuase the  Jet stream  will continue to dig southward from MN IA  and the Dakotas.  This   will cause the trough to expand  down to Georgia and Florida  on the  19th.    Because a trough will be so deep and amplified    (  that is ti say …  running   south to North)  the the surface  cold   front will stall either over the Appalachians OR  over the coastal Plain on the Atlantic seaboard.     This will allow for a new Low to form — which is referred   to as   “  SECONDARY  Low”  –   over the southeastern states on the  19th.  This could be a major rain event for the entire East Coast as well as the Appalachians.

      

But the significance of this feature is that when secondary LOW     blows up the coast it will eventually merge with the remains of the primary Low over the eastern Great Lakes .  Together this feature will become a  Huge pressure over  eastern  Canada/  Quebec and move  up across Hudson’s bay Canada .     This   LOW will be the first developing  POLAR  VORTEX   (PV)  of the  cold season.     The PV is a very critical aspect to the overall pattern in the western hemisphere during the  cold  months.  The  PV is a large  quasi   stationary   Upper  Low  in the Jet stream which is located  around the Western hemisphere at the high latitudes.   The position and location of the vortex has a significant impact on the overall position of troughs and ridges ….and possible Low   pressure  tracks and development of   Low pressure  areas … all across North America .

 

For example if the PV  is not located over Eastern Canada than  it is very hard to get any sort of sustained colder outbreaks over the eastern half of  of the CONUS.

The absence of the   PV can mean many different things .  For example if    in    “COLD ” months — NDJFM–    the PV  is located over Alaska   or  northwestern Canada that implies that all the arctic air as bottled up over   eastern  Asia /  Siberia and there is no  way to get sustain cold air anywhere into the central and eastern portions  of the CONUS .      Sometimes the PV    can  and will  leave North America and move to Greenland.    Not only would this establish a very positive  NAO…  but if the PV  were to leave Greenland and move  into   say   Iceland   or Scandinavia this would ensure that the next few weeks over North America would not feature any sort of sustained prolonged colder outbreaks .   ( the key word here is sustained ). 

On the other hand if the   PV  were to be suppressed   to the south  — because of strong blocking over Greenland    –this could lead to a potential significant East Coast winter storm over some portion of the eastern third of the U.S..

The point here is that in order to get a typical cold season   pattern one needs to have a large and well develop PV  somewhere over central and/or  eastern Canada.  The development of the  Midwest  and  coastal Low  OCT  18-19-20 appears to be a excellent candidate for the development of the first PV  of the winter season!
Hoooray!!!

 

FIRST BIG EASTERN US COAST LOW OF THE SEASON

Posted by wxrisk | GENERAL,WINTER 2011-12 | Monday 17 October 2011 8:15 pm

17   OCT  2000  HRS  EDT   

Over the past few days there been some pretty bad forecasts out there with regard to the upcoming coastal storm which is going to develop in the next 36 to 48 hours.    Most of the forecasts have been calling for a chance of rain may be some thunder blah blah blah… for Tuesday night and Wednesday and Wednesday night along the East Coast (and depending on your location).    It is all very generic and pretty close to being meaningless that sort of bland generic forecast really doesn’t convey ANY useful information to YOU …. whether you are just a person of the general public or if you are running a business which has some specific weather concerns .

Part of the reason why the forecasts    have    been so bland from late last week …   and  over the  weekend …  with regard to this upcoming system for the 19th is that many of the weather models have ignored the development of this tropical feature in the northwest Caribbean over this past weekend.   This feature which is now over the southeastern Gulf of Mexico is clearly going to be pulled into the developing a deep trough over the East Coast.

As I stated over the weekend…  and from last Friday… With each passing model run as the global and the short range models see more and more of this tropical feature the rainfall amounts are increasing along the East coast.    To me what is typical and bothers some is that the number of forecasters and their forecasts which seem to have completely missed this obvious connection because it is not  staring them in their face on the GFS model from 2 days ago.        It’s supposed to be meteorology NOT Modelology… ya Know?

Let me give an example of the increasing rainfall shifts in the models that were seeing . This first images from the 0z Monday OCT 17 run of the GFS Model that shows the total rainfall for a 3 day period– from Monday 8am to Thursday am EDT.   As I have highlighted there is a clear and distinct a gap in the rain shield –one area heavy rain is associated with the main piece of upper level energy over the Midwest and the Great Lakes…  and the second area of heavy rain is associated with the Low coming up from the Gulf of Mexico over the southeast coast.     However the 12z GFS from Monday OCT 17 run…   Shows a significant increase in the amount of rain.

WHY?     The primary reason is that the models are now   ”seeing “    the large and impressive system developing in the Southeast Gulf of Mexico.

The hurricane center this Monday afternoon did NOT find a tropical depression per se … But the infrared satellite picture from this morning showed the impressive looking system.

 

The other important aspect of the system which is instructional to see… is that the coastal Low gets captures by the deep closed off 500 mb Low over the Midwest.   The 500 MB develop a negative tilt as we can see here— shown by the European model. But all the models are showing the same thing here so there is not really any variance to talk about.

  

These 3 images of the NAM show this capturing of the surface Low by the 500 mb closed Upper Low very nicely. In addition you can see the surface Low really bombs out as it moves into the Ohio Valley and the eastern Great Lakes.

      

 This capturing of the coastal Low and the Low getting pulled NORTHWEST under the 500 Low …can often cause a lot of weather hobbyists and weather weenies a lot of anguish and frustration especially during the cold season/ winter months.   If this was say January storm then we would be looking at primarily a rain event for everybody on the East Coast from Boston to Richmond… Even into the mountains of VA MD PA and eastern NY.
It now appears to be a very similar type of event developing OCT 27 over the Midwest and East coast. In fact there have been several significant troughs and eastern U.S. Low pressure areas in the past 45 days but most than had been England or Midwest type of events.   This by itself does not mean anything…. But it is instructional in showing the impact of NOT having a -NAO or Blocking pattern of any kind over eastern third of Canada / Greenland.    If we did then a lot of these systems would be classic of coastal storms or Noreasters

 

**** PRELIMINARY WINTER FORECAST 2011-12 ***

Posted by wxrisk | GENERAL,SEASONAL FORECASTS | Monday 10 October 2011 1:18 pm

  1530   SUNDAY     OCT   9  2011

  this  should    link will  take  you to a page  where    a   MICROSOFT    Power Point  opens  up  …

http://tinyurl.com/6gjhx5o

 

 

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