***  SPRING   FORECAST   2009   ***

 

 

 

 

  The Spring season of 2009 is going to be dominated by the   three significant   features

  1. The continuing weak to  Moderate   La Niņa event which   developed   ...unexpectedly...  in the middle  of the  Winter of 2008-09. 
  2. The   large  persistent  Negative PDO  (hereafter  referred to as the -PDO)
  3. The   developing   DROUGHT   over the  Deep south and  wetter  than Normal Soil    moisture conditions over the   Plains and  Midwest.

 

 These  features... along with a  few other  less influential  factors   will  ensure that   SPRING  2009  is going to be essentially a  repeat of the cold  Wet Spring   the   Plains and Midwest  experienced  in the   SPRING 2008.

 

  That being said let  me  state  as clearly  as I can   that this .. and ALL private    weather forecasts  as well as those  from CPC    for the  SPRING   and SUMMER  2009 will be  highly  dependent on  the   current  weak/ Moderate La Nina   event.

 

  Many of the forecast models are currently calling for an end to the weak/ moderate La Nina by late in the Spring / early Summer 2009.  In fact some of these climate models are forecasting a weak El Nino to develop by the middle of Summer 2009. However since the current La Nina event was poorly forecasted by all of the ENSO climate models from just a few months ago there is a great deal of uncertainty as to whether or not the La Niņa event will hold on  dissipate  or actually become a weak El Nino event by middle of Summer 2009. In any event  you need to keep in mind that a lot of these "early" SUMMER 2009 forecasts being issued in late February and early March are based upon some very risky ideas.

 

 

 

   

 SPRING FORECAST MAPS

  

 MARCH JET STREAM    MARCH   TEMPS   MARCH    PRECIP
 APRIL JET STREAM   APRIL  TEMPS   APRIL  PRECIP
 MAY JET STREAM    MAY   TEMPS   MAY   PRECIP

 


 

 

 METEOROLOGICAL   REASONING

 

 

REVIEW   OF WINTER    2008-09

  The link below shows the WxRisk WINTER  2008-09 forecast.  My Winter  forecast was  NOT a good one.  Though DEC 2008 was cold east of the Rockies  I was   too cold.  I was  also too warm  for  JAN  2009  and too stormy with the pattern  for the  eastern  CONUS    for February  2009  ( I  had  way  too snow) .   On the other hand I knew by  DEC  7 2008  that  My Winter forecast  was    NOT going  to   work out    where upon I issued  a   SPECIAL  CLIMATE FORECAST STATEMENT   on DEC 9.  

 

 Click HERE  for  WXRISK.COM'S   WINTER  2008-09   forecast  Maps

 

   Sometimes meteorologists tried to make seasonal forecasting too much like rocket science or brain surgery. And sometimes there is a lot of uncertainty within the atmosphere with regard to the seasonal forecast and looking at long-term signals. But the spring forecast 2009 is not one of those difficult forecasts to make. The signals and driving influences are pretty strong. In addition we have the advantage of considering the previous spring of 2008. In many ways the atmosphere and ocean water patterns are very similar to what we saw in the late winter and spring of 2008.

The Winter of 2008-09  over the   Upper Midwest  and Upper Plains has been fairly close to what we experienced last Winter.   If you recall the previous Winter of 2007- 08  it featured near record snowfall over New England and much of the Midwest and eastern portions of the Upper Plains. There were a number of factors which lead to this exceptionally snowy and cold pattern for the Midwest and since these factors did not change... the  Spring of 2008  was  essentially  a  continuation of the  WINTER  20007-8  pattern. In other words  very cold and very wet. 

 

  The factors that  lead to such a    cold and wet  Spring 2008 were   for the upper Plains and  Midwest:
 

  • A Moderate  to  weak La Nina
  • A Negative PDO
  • Large areas of excessively wet surface and subsurface moisture across much of the Plains /Midwest.

 As you will see throughout  this discussion the   atmospheric  conditions   entering  the SPRING 2009  are   quite   similar  to   SPRING 2008.     These first two imaged show the temperature anomalies.... since 1 JAN ... and over the last 30day. You can clearly see that temperatures have been running above normal for most of the Plains from SD into  TX as well as eastern Rockies while over the Midwest especially east of  the Mississippi River temperatures have run Below Normal.

 

      

 

      These next two maps show you the precipitation patterns for  current  Winter ( 2008-9). The first one shows you the  precipitation over the last 90 days... with a lot of very dry conditions over Texas and the lower Plains with a secondary area of dryness over the Southeast coast .  There is also an area   of  Much Above Normal rainfall over the upper Plains.      The second image shows you the 30 days .  Note the increase in large areas of Below Normal rainfall from eastern PA   down into GA  and across the entire Gulf Coast and into the lower Plains and NM ... and  the two areas of Above Normal rainfall... one over the western portions of the upper Plains and the other area covering much of Lower MO into the ECB.

      

   


 

SEA SURFACE  TEMPERATURES:  THE   -PDO  

 

Over the  last   10 years there has been a significant amount of   research  done  on a    longer term  Climate pattern   that   is   called the  PDO in the weather biz.    The PDO     or   "Pacific Decadal Oscillation"     a long-lived   climate  pattern   that    exists over the northern Pacific Ocean. 

The  PDO   involves the location  and intensity   of   large pools of  warm and /or cold   Seas Surface   Temperature anomalies  (SSTAs)   in the  central and   eastern areas of the  Northern Pacific.  Why is this important? Again     research  has  shown that large  areas  of   warm and cold  water   pools     called     SSTA  couplets    STRONGLY affect the    Jet stream pattern and the   positions of    Ridges and troughs  within   the Jet Stream over the   Pacific   and  western North America.

This is   diagram   shows    you    the Two phases  of the   PDO... the      BLUE  color    represents   very cold  SSTAs...    the  Green    cool SSTAs.... the  Yellow color  represents   warm SSTAs ... and  the    RED color  very  warm SSTAs. 

 

 

 

 

 

 

 

 

   Basically  during  the  SPRING   season ...a   WARM  Phase  of  PDO ... also called +PDO   supports a   Ridge in the Jet stream along the  West Coast  (warm & dry)  ... a trough over the   ECB and the Northeast   (cold and   wet)   while the  Plains  is  seasonal and   dry.

 

   During the  SPRING   season  a COLD  Phase of the PDO ... also called the -PDO   supports a    Trough on   the West coast/ Rockies  (colder/ wetter)....   a  Ridge over the  Deep south or Southeast States  (warm & dry)... more   warm & dry  conditions over the Lower  Plains... a  a stormy  wet cold pattern   for the central & Upper Plains and all of the Midwest into New  England.  

 

 

 

 

 

 

 SEA  SURFACE   TEMPERATURE  ANOMALIES    SPRING 2008

 CLICK ON   MAGES  TO SEE     PERSISTENT  COLD   WATER   ALONG WEST   COAST OF AMERICA  ALL  SPRING 2008
10 MARCH   2008
24 MARCH 2008
10 APRIL  2008
24 APRIL  2008
10 MAY 2008
24 MAY 2008

    

     In case you forgot    this is what the   SPRING  2008  looked  like   with  respect  to temperatures and    precipitation .    It  was a  COLD    and WET  SPRING.  

 MAM=  March April  May        

MAM   2008 TEMPS 
DEPARTURE FROM NORMAL

MAM   2008  PRECIPS 
DEPARTURE FROM NORMAL

 


 

      WHAT ABOUT THE  PDO   RIGHT NOW ?

 As you can see from these current sea surface temperature maps the SSTA (sea surface temperature anomalies) are very close if not almost identical to what we saw been the late winter and early spring of 2008.   The large area of Cold sea surface temperatures in the eastern Pacific were directly associated with the negative phase of the PDO and the Moderate La Nina.

And for most of the Winter  of 2008-09   going into this SPRING  of 2009 again we see large areas of cold sea surface temperatures correctly associated with a strongly negative PDO event and Moderate but weakening La Nina.

This is one of the primary reasons why WXRISK.COM is forecasting a repeat of the 2008 Spring pattern  for   the Upper Plains and the Midwest for the  Spring of  2009.  Really it's not brain surgery. The same conditions bring about the same pattern.

 

  26 JAN  2009   SSTAs   9  FEB  2009  SSTAs   23  FEB    2009    SSTAs

 

 


 

                 WHAT ABOUT THE  LA  NINA  ?

   The biggest single uncertainty regarding the forecast for SPRING  and  SUMMER 2009 is the status of the Moderate/ weak La Nina event.

  As I stated in the beginning of this discussion the redevelopment of the La Niņa event was a surprise to come climatologists and forecasters alike. This was the first time in many many years that we actually had the La Nina event redevelop during the winter months!

 

    

 

   In many ways this current  La Nina episode  is similar to we saw in the Winter and Spring of 2008 but that event was somewhat stronger going into the Spring of 2008 than this current one.  Even so by MAY 2008 that La Nina episode had greatly weakened and was essentially over with by the time we reached Memorial Day. Of course that played havoc with a lot of the summer forecast from many private agricultural forecasters since many of the SUMMER 2008 forecasts were premised on the idea that the moderate/ weak  La Nina would continue right through the entire  Summer of 2008.

Of course as we now know that did not happen.

 

The  January and February 2009   weather patterns over North America are clearly under the influence of a moderate La Nina but this one does appear to be somewhat weaker than the La Nina episode of JAN / FEB 2008. The issue then becomes the rate of decline.

This image shows the forecast from the CFS Model.

     The CFS is the official Climate forecast model used by the National Weather Service and  the  CPC -Climate Prediction Center. This model is popular and well-known by a lot of private energy and agricultural meteorologists but it is a pretty bad climate model as these things go.

 For   example...  the CFS Model completely missed the developing La Nina event this winter and the poor performance of the CFS is one of the primary reasons WHY so many meteorologists and climatologists completely misread  the Winter 2008-09 forecast.   Recall that most of the private and government forecasts called for a milder than normal winter for the CONUS east of the Rockies  ( which did not happen).    Because everybody relied upon the CFS climate model the assumption was that there was not going to be a weak to moderate La Nina event  during the Winter of 2008-09.    This is important because there is a strong connection between colder than normal winter is and Weak La Nina events.

The point is.... that the latest CFS shows the weak La Nina episode dying and a shift towards a weak El Nino by the end of the Summer 2009.

 

However there are other climate models out there which good seasonal forecasters should be looking at and these climate models come up with a significantly different forecast.

 This link shows you the latest computer models from the middle of February which are used to forecast La Nina and El Nino events out to 1 year. 

    This graph comes out every month and the important thing to note here is that this current chart clearly shows that  MOST of the  forecast  Models  do NOT   end the  weak  La Nina  this  SPRING   or   EARLY SUMMER.

 


 

      SUBSOIL   MOISTURE

   Many farmers and agricultural traders as well as agronomists know the old adage that drought begets drought and rainy patterns beget rainy patterns. There is a lot of truth to that and some sound meteorological reasoning to support those old adages and sayings.

Large very dry areas during the warm months of the year have what is called a "positive feedback". That is to say the hotter and drier the ground over a large area the more HEAT goes into the atmosphere which in turn feeds the development of any sort of Heat Ridge or Dome. In a similar manner... large areas of excessively wet ground often allow for the mean trough position to stay in the same general location which supports more additional rainfall and cooler temperatures... which in turn restricts the evaporational process.

 

Coming out of the Winter of 2007-8 the excessively stormy/ snowy conditions over the Plains and Midwest produced a large area of exceptionally wet and supersaturated ground conditions. This image shows you what subsoil moisture conditions look like exactly 1 year ago -- at the end of February 2008. The large areas of dark greens and dark blues speak for themselves.

                                                              23  FEB  2008

 

 

As I stated above there are SOME similarities between the late Winter / early Spring 2008 subsurface moisture to the CURRENT late Winter subsurface moisture conditions. This image shows the current LONG TERM    drought  map. The Long-term image shows a significantly wetter than normal subsurface moisture conditions over much of the central  and upper Plains and into the Midwest / WCB.

 

and  this image is the SHORT TERM DROUGHT   map across the CONUS as of late February 2009.

  In the  Short-term image we can see conditions have not been nearly as wet over the last few weeks with most of the Above Normal moisture restricted to Upper Plains.

 

So in the general sense there is some similarity  between  FEB 2008  and FEB  2009 but there are also some important differences.   Both the Short-term Drought Map and the Long-term drought maps show increasing areas of very dry conditions over much of the Deep South from Virginia into Texas.      It is already well known that the Lower Plains (KS OK TX) has been experiencing an exceptionally DRY Winter and that is reflected in these maps. Over the last few weeks the very dry conditions have expanded into the Gulf Coast and up into the Carolinas and Virginia.   WXRISK.COM believes this trend is going to continue and intensify as a moving to the SPRING  2009  and there is high probability of a drought of some sort of intensity being declared before the end of Spring 2009 over TX/ OK and possibly including much of the Deep South.

 

       This assessment is based upon the continuing strongly -PDO along the weak La Nina effects combining to keep the current overall weather pattern in place right through the early Summer of 2009.

   


 

    WHAT  ABOUT SUMMER  2009?

 

 

 

     Any SUMMER 2009 forecast that is issued at this early stage is going to be a real crapshoot . In one sense I suppose that is true for any sort of long-range seasonal forecast . But sometimes the pattern is so strong obvious and locked in that a general forecast can be made. That is not however going to be the case this time around.

 

Since we have weak La Nina on going the first thing any forecaster has to do is figure out whether or not the La Nina will die off... hold ... strengthen or perhaps shift   to a El Nino event. The wide disparity in the computer models at this early stage is really not going to help things.

 

In addition we have been in a strongly negative phase of the PDO for some time now. There is some possibility that the PDO may begin to move towards more neutral condition by late spring or early summer again at this point time that is really just a speculation.

 

The bottom line is that right now I do not have any strong indications of at about how the Summer of 2009 is going to shape up. I could easily see a scenario where the developing drought over the Deep South expands into much of the Midwest as the jet stream typically shifts to the north (as it typically does in the Summer months). On the other hand I can also see how the pattern might evolve into one where the drought stays over Texas the Delta and the Deep South and the upper Plains and Midwest stay fairly close to seasonal with regard to temperatures and precipitation.