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                                               SUMMER  2010   REVIEW  

 
     
 

 REVIEW      issued 20 OCT 2010     

WXRISK  EARLY SUMMER FORECAST
 JUNE 1 to JULY 15
WXRISK  LATE SUMMER FORECAST
JULY 15  -   AUG 30
WXRISK   HURRICANE FORECAST
JUNE JULY AUG 2010
RAINFALL   DEPARTURE
  FROM NORMAL
JUNE JULY AUG 2010
TEMPERATURE  DEPARTURE
 FROM  NORMAL

This is  the  Kind of  pattern I expect for the 2010  Hurricane  season: As you can see with the  mean Ridge  in the Jet stream in place   over the  Deep South   I anticipate a    trough in the  Jet stream somewhere  " downstream" ...in this case over the    Central Atlantic  ocean.  This trough will at times  be   "deep" enough to  cause  early  what is know as  "re-curvature" of     TC  coming  east.

In Addition  the   large mean ridge  in the Jet stream over the Deep South will  great    REDUCE  the threat of  numerous   Gulf of Mexico season.  Thus besides   the high likelihood of  numerous  TC in the   Tropical  Atlantic being turned out to sea  early  there will  be a  2nd area of  increase threat of  TC  activity   NW Caribbean-  Yucatan  and   sw Gulf  (Bay of Campeche).    One or two   TC  might reach  far southern TX.

 

JUNE  2010   RAINFALL
DEPARTURE  FROM  NORMAL
JUNE 2010 TEMPERATURE
DEPARTURE  FROM NORMAL
JULY   2010  RAINFALL
DEPARTURE  FROM  NORMAL
JULY  2010 TEMPERATURE
 DEPARTURE   FROM NORMAL
.
.
 AUG 2010 RAINFALL
DEPARTURE   FROM   NORMAL
AUG  2010  TEMPERATURE
DEPARTURE  FROM  NORMAL
.
.

 

 

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

 There is an increased   RISK   (Not  probability  just  RISK)  of a   DROUGHT  in the   2nd  Half of the Summer into  Early  Autumn  over the  some portion of the  Midwest and  Deep South.  

 

    For the better part of the year the weather pattern across North America has been persistent and unyielding.  From  the Spring of 2009...  through the Summer... Autumn and into this past Winter we have seen the same pattern stayed locked in. 

The pattern has featured a persistent Trough in the Jet stream and persistent blocking  in the  High Latitudes over Eastern Canada and Greenland.  The blocking pattern during the Autumn of 2009 and Winter 2009-10 reached record levels ...  Stronger and more persistent than any other high latitude blocking  in six month period  since meteorologist and climatologists started keeping track of blocking patterns  (back to the 1950s). 

 In addition at times this pattern has also been aided by a persistent ridge over Western Canada  AND the Moderate  / strong  El Nino event   (known as a  WARM ENSO event in the  weather  biz)   that developed  in the late Summer of 2009 and  lasted  right through the   Winter of  2009-10 into the  early  Spring  of 2010.

 The  combination of these  four   factors has produced large areas of persistently Below Normal  and Much Below  Normal temperatures over the Plains  the Midwest and northeast  Conus.  The pattern  over the past 12 months has  also been a persistently...  and at times...  excessively wet one with many areas across the Plains and the Midwest experiencing Much Above Normal with respect to soil moisture and the soil saturation.  Many areas from the Plains to the Northeast have seen  ground soil  conditions  that  have  been super saturated for months at a time.

  Agricultural traders can be easily recall the excessively wet Spring of 2009...  the   record  cool Midwest Summer... and the record shattering cold and wet September and October in the Autumn of 2009.

 

   KEY ASSUMPTIONS  & PREMISE

   That pattern is over and something new is developing.  The evidence for this is apparent already in the spring 2010 season and in the changes of the overall hemispheric pattern.  SPECIFICALLY:

1  The persistent high latitude blocking over Eastern Canada and Greenland is no longer in position

2 The persistent ridge over Western Canada  has  been replaced by  persistent trough over the  West coast 

3  The   El Nino of 2009 which began to fade  in late February and early March  2010...is now falling at a rapid rate and should soon reach neutral conditions by early to middle MAY 2010.  

4.  Rainfall patterns have turned dramatically Drier  over the last 45 days with large areas of the Plains and the Midwest seeing below normal rainfall for the first time in over year.

   

 THE  BOTTOM LINE  is this: the old weather pattern that has dominated  North America  is over.  It is dead.  Something new is coming.   Any Summer2010  forecast  that that was premised on the idea   that the weather pattern of the past year would continue...  is going to  bust.

 

 WHAT  WILL THE NEW PATTERN   LOOK LIKE AND WHAT WILL IT MEAN?

 

Without a doubt the overall driving factor for  THIS  Summer 2010... and  ANY forecast   for the Summer 2010 has been the   status   of the El Nino.  Most of the long range computer models which forecasters rely on to get an idea of the  El Nino  and its  trends in the future...  have consistently showed that the current El Nino would continue through the Spring and slowly  fade  over the Summer of 2010.

   That  assumption  is wrong.  As you will see  the   El Nino is weakening  RAPIDLY.  Thus  ANY Summer  2010 forecast  issued   back in March  or  early April are therefore premised upon a key factor which is no longer likely to occur.

 

 The data over the last few weeks shows a rapid  weakening of the El Nino. The new climate models are showing a strong trend  for the  El Nino to  drop to Neutral  conditions  early this Summer and  shift into a La Niņa event  which develops  in the second half of the Summer of  2010. The  new data shows  La Nina   has a good chance to  become  a Moderate  La Nina  event  by  early in the Autumn 2010.

    

  This WxRisk.com  Summer 2010 preview forecast is based strongly on this trend.  The European El Nino forecast model based upon March 1 show a strong trend  the  SSTA  (sea surface temperature anomalies )  developing over the El  Nino  regions starting in July and becoming moderate by August September and October.    The NEW   updated version of these forecasts in  SSTA  (April 1)  show a even more rapid trend  towards a  La Nina event.

  Significantly back in the month of March most of climate models did NOT agree with the European climate model  that  showing the rapid cooling over the El Nino regions.  However the new April climate models are now significantly colder and have moved  much closer  to the European Model of a  moderate La Nina   even  developing  in the 2nd half of the Summer and into the  Autumn of 2010.

    

   WHY is this significant?   There is a strong correlation between the development of drought conditions over some portion of the Plains and or Midwest and Moderate or  strong  La Niņa conditions.

  Since  1999...  when WxRisk.com  began seasonal agricultural and energy forecasting  I have never forecasted  a    drought... or  the risk of  a  drought over a significant portion of the Midwest.   Unless the data changes.. when I issue the official Summer 2010 forecast...  ( about 5/20/10)    I probably will be forecasting a high a risk or threat of seeing a significant drought LATE  in the Summer  into the Autumn  of 2010.

 We may already be seeing the beginnings  of this new  warmer  & drier  weather pattern and how  things  COULD  evolve into a  potential  Drought pattern.  The development of the persistent trough over the West coast has brought California... the  Pacific Northwest and much of the southwest  states a pretty nasty chilly Spring 2010 with Below  and Much Below Normal temperatures and Much Above normal rainfall.    This  image  is   a  cleaned  up  map of this   European Model   analysis of the  atmosphere  from  Mid April.

 

  EURO MODEL  OF  ATMOSPHERE  VALID  APRIL 15

  

 

 

As I said  above this is a fundamentally different pattern from what we have seen over the past year across North America.

   Because it is still early in the warm season...  the parade of  Low pressure areas coming out of California  are tracking  ENE through the central Rockies and into the Plains and the Midwest.  Therefore in terms of sensible  or   "actual" weather   it appears that the pattern is still staying stormy and wet.

  However... in response to this persistent trough over the  West coast ...the atmosphere has countered this by developing a ridge in the Jet stream over the Lower Plains and the Deep South.  This has resulted in  warm conditions over the past 45 days with respect to temperatures  which have been running Above normal over the    lower half of the Plains    the Deep South and Midwest and somewhat Below Normal  rainfall.

  

 As we move into the late Spring and Summer   the persistent trough over the West coast will shift to the north because the main jet stream position always shifts to the north as we approach  the Summer  season.   This means that eventually the Low pressure areas  that are  Now   coming  out of central and Southern California will instead into  come out of  Northern California  and/or Oregon.    These   systems will still    track ENE   but instead of moving through the central Plains   then into the Midwest ...these   weather systems  ENE track  will take them across and northern Rockies and into Southern   central Canada and perhaps the Dakotas and western Great Lakes.

 To the south the Ridge which is currently centered over the Lower Plains and the Deep South will begin to expand to the north and west as the jet stream shifts to the north and west.    This will allow drier in warmer conditions to develop during the late Spring and early Summer.

  As the  La Nina strengthens   and kicks  in...  The ridge over the Deep South will continue to strengthen and expand.  This sort of scenario is  based  on a  classic moderate La Niņa drought scenario.

 

 

   SOIL   MOISTURE
  the over looked  clue  in seasonal forecasting

 

 One of the most overlooked aspects to forecasting seasonal weather patterns has to do with soil moisture. I Am not sure why this is the case but a lot of seasonal forecasters and climatologist often overlooked the impact that large areas of the excessively wet ground or super saturated ground and large areas of very dry or drought conditions can have on the overall pattern.

For example the great drought in the Summer of 1988 followed a very dry winter of 1987-88 and Dry Spring of 1988. These are all part of a strong La Nina event.

In using the soil moisture conditions and patterns as a clue as to what the upcoming season might look like one has to be careful. Using the soil moisture method for seasonal forecasting really only works IF and only IF... you have large areas of excessively wet ground / soils and large areas of excessively dry soils.

Let's take a look how this works. It is a well known and proven weather "saying" that drought begets drought and a wet pattern be gets more wet patterns. The reason that these "sayings" are valid hass to do with something called positive feedback. Large areas of dry grounds give off excessive Heat and lower than Normal Humidity especially during the hot Summer months. This additional heat feeds into the atmosphere and reinforces a ridge which might be in place at the jet stream level. Likewise large areas of really wet ground often mean that the soils are colder than normal and the excessive low level humidity from the wet soils feedback into the atmospere in such a way as to keep the mean trough position located over a general area.

These NEXT   two  images show the soil conditions moisture from last of all autumn-- NOV 7 2009 to be exact. The first image represents the LOMG TERM TREND ( the past few months) and the second image represents the SHORT TERM TREND or the past few weeks.

    

As you can see their large areas of extremely wet soil conditions covering all of the Midwest... From the Delta to the Great Lakes with a secondary area of wet conditions over the Northeast. There were also fairly dry conditions along the West Coast. The SHORT TERM TREND map showed that these are excessively wet soil conditions was continuing and if anything expanding into the deep south and the Delta .

My argument from last autumn was that the very cool Summer and sept and OCT of 2009 was just a precursor of the winter coming up. This was suggested / forecasted because of these very wet conditions which supported the mean trough being located over the Mississippi river valley . From that position any significant Low pressure area would come out of the Gulf of Mexico track up the East coast and bring large areas of heavy snow and Below Normal temperatures especially for the Northeast but for the Midwest in general .

 

As we know that is exactly what happened this past winter .

These images show the actual winter conditions (DJF) with respect to precipitation and temperatures. Notice that the Midwest east of the Mississippi River-- the ECB-- actually saw Drier than normal conditions while the East coast from Georgia to Maine experience wetter than normal conditions. With respect to temperatures ...the Northeast actually saw temperatures that were close to normal but to the West there were large area of Below and Much Below Normal temperatures across the Upper Plains and all of the Midwest into the Deep South .

 

      

 

That sort of temperature signature can only result from the mean trough position being located over the Mississippi Valley and the Midwest.  The   SOIL  MOISTURE   METHOD  in a text book perfect  manner!

Now let's take a look at the long-term and short-term trends with regard to the current soil moisture conditions across the CONUS.

This first image - LONG TERM TRENDS-- show that while the Midwest areas and the eastern Plains are still wetter than normal they are significantly drier than what we saw last November. The SHORT TERM TRENDS are even more impressive showing their large areas of the Great Lakes OH and KY are now drier and in some cases significantly drier than normal.

      

SUMMARY: the continuing drying trends over the Great Lakes and especially the ECB is additional proof that the overall pattern from the last year has come to an end. If this trend continues the dry conditions over the ECB could support the potential for a drought to develop late in the Summer of 2010 over the Midwest east the Mississippi River.

 

       THE   CAS   CLIMATE   MODEL
 

The CAS Model is the only climate model which actually uses the Soil Moisture conditions to forecast the next 3 to 4 months.

Research shows that the CAS climate Model is actually very good forecast four temperatures and moisture / rainfall for the next 30 days. Beyond that as is all climate models its reliability and accuracy rapidly weakens especially if further out and time you go.

However if you have  areas of the excessively wet or dry conditions the CAS can be rather useful tool. In addition one of the good things about this climate forecasting tool is that it is updated every two days so that forecasters can actually track the trends of cold and warm dry and wet over several days and several weeks.

These first three images show the CAS model temperature and precipitation forecasts as of APRIL 14... valid for JUNE JULY AUG of 2010. As you look of these models you should notice that in none of the 3 months is the CAS forecasting wetter than normal conditions over the Midwest . In fact in June and in August the CAS is showing large areas of Below Normal precipitation over portions of the Midwest.

With respect to temperatures notice that the trend clearly shows that July and August will be significantly warmer relative to normal over the Midwest then June.

                         

 

Looking longer term these 2 images are the CAS climate model forecast for three month increments... JJA- June July August... JAS= July August September and ASO = August September October.

Again what is Noticeable about these maps is that relative to Normal ... temperatures in the second half of the Summer and early Autumn of 2010 are clearly warmer than Normal. And with precipitation we can see large areas of Below Normal rainfall persistently located over the ECB.

It will be very interesting to follow the CAS Model as you move into may to see what changes if any a showing with regard to the summer months .

  

                       

  

   

 HURRICANE  SEASON   2010.

In a word it is looking bad...  REALLY  bad with  respect to  overall TC activity.  Those of you who get the energy   and Hurricane forecasts from me know that since 2005 I have NOT  been caught up in the  media hype about forecasting another monster hurricane season like  we s aw in 2004 and 2005. .

  Indeed back in 2006 numerous private forecasters  became  caught up in a game of    "I can top that forecast".   They  went   extreme with the early season Hurricane forecast... whereas  Wxrisk.com   actually  forecasted the lowest  Tropical  Cyclone activity in the Atlantic Basin of any of the well-known private forecast services.   I remained  bearish on hurricane activity throughout the 2007 and  2008 hurricane seasons as well even though in many of the private forecast services continue to over forecast the amount of tropical activity   in the Atlantic Basin.

  That  Being said... over the past 30-45  days I  have become  awed by the extremely warm  SSTA which have developed throughout the spring across the entire  MDR (main development   region)  but especially over the central and eastern portions of the tropical Atlantic.  These warm SSTA  are far warmer than anything on new record easily exceeding the warm waters we saw in 2005. 

 

   

 In addition there is a strong correlation between Above Normal hurricane activity and moderate  La Niņa events..  and between   strongly  negative   QBO  phases  and   Above Normal hurricane activity.

   As long as the WIND shear is not too strong and the Saharan dust is not overpowering...  It is very possible that the 2010 hurricane season could equal that of 2005 or perhaps even exceed  it.  It is way too early in the season to speculate about the amount of Sahara dust that will get into the far eastern tropical Atlantic   or the  shear  across the   Caribbean Basin and tropical Atlantic regions .   If  the  Pattern  does  develop as  I  am forecasting   the   Ridge over the   SE    states   will  prevent   Hurricanes  from turning out  to  sea once   they reach   65  west Longitude  and   steer systems into the   Gulf of  Mexico.

 This is  the  Kind of  pattern I expect for the 2010  Hurricane  season: As you can see with the  mean Ridge  in the Jet stream in place   over the  Deep South   I anticipate a    trough in the  Jet stream somewhere  " downstream" ...in this case over the    Central Atlantic  ocean.  This trough will at times  be   "deep" enough to  cause  early  "re-curvature" of     TC  coming  east.

In Addition  the   large mean ridge  in the Jet stream over the Deep South will  great    REDUCE  the threat of  numerous   Gulf of Mexico season.  Thus besides   the high likelihood of  numerous  TC in the   Tropical  Atlantic being turned out to sea  early  there will  be a  2nd area of  increase threat of  TC  activity   NW Caribbean-  Yucatan  and   sw Gulf  (Bay of Campeche).    One or two   TC  might reach  far southern TX.