Posted by wxrisk | GENERAL | Saturday 23 June 2012 1:54 pm

1300 EDT  23  JUNE   2012



back the middle of  June …I talked about the shift of a pattern in the  second and  third  weeks where the heat dome would be forced to back  into the Rockies and Midwest  would see an  interval of seasonal temperatures over the Midwest.  That process is underway right now and will continue for good portion of next week as well.

  SUMMARY …  However I am still concerned that   the pattern is  going to enter an interval in the middle of July– specifically after July 5th– that will bring wetter than normal conditions for the Midwest at a very important time for the US  corn  crop.  Exactly   “HOW  WET? “    this interval will be and   “HOW LONG?”   it will last I am not certain of but it seems to me at least a week or 10 days seems a good probability.  That being said keep in mind that the Midwest area is under a growing and persistent drought so if   this   ‘wet” interval    features conditions that are wetter than it has been….that does not necessarily mean is going to be wether than  normal. 


Historically the month of July  when the MJO  moves into quadrant or phase 3 …produces Above and Much Above Normal rainfall over the Midwest .  Increasingly more and more of the various MJO Models show the current   MJO impulse moving into phase 3  after July 5.  It is on that basis that I am forecasting a wetter pattern developing for the Midwest during the middle of July.

This  map is from the GFS  DAY 10 ensemble    mean  and    it  clearly  shows the  persistent   West coast trough…  and the  East coast trough   and the   large Heat Dome/ ridge   covering  the    SW  states  into the  Lower Plains and  the  southeast    states.   We can also  see the   high latitude blocking over    Greenland and eastern  Canada. If that Blocking   feature was not  there… the Heat would   surge be  back into position…  covering  the Midwest and East coast .

By  DAY 15…   the  Heat dome /  Ridge is   just as pronounced    but it is  FURTHER SOUTH… than  what  we  have  seen   over the past 60-90  days.    The ridge / dome  covers   all of the SW  states and the Lower Plains  into the  Delta.    Again the powerful Blocking over   Northeast Canada   — the   negative NAO  –   keeps the dome / ridge   SOUTH .      When the  Dome / Ridge is shaped like this  and in this  geographical  position   the pattern  supports    “ ring of Fire “ Thunderstorms over the   Upper Plains into the  Upper Mississippi river valley  / northern WCB.



We can  see    the  GFS  and  ECMWF   ensembles  mean   RAINFALL   for the  6-10 DAY    and the  11-15 DAY    are now reflecting  an increase in showers and  storms



of course   this is from the GFS ensemble  mean which while good… is not   that  reliable.    This next image shows the latest computer forecasted models for the current MJO   impulse  which has intensified  rapidly since JUNE  4.  What   is important to note here is that all the model data moves  the MJO from its current position  in  quadrant  1  …  steadily through   quadrant  2  and then quadrant  3  by July  7-10.


This next image is from the CPC– climate prediction center.  It shows what the JULY MJO  rainfall patterns look like   when the MJO moves through the various eight different quadrants.   If you take a look at  quadrant   3  which is where the MJO  is  going to AFTER JULY   5-7.. you will  see that the Midwest is covered with the  DARK   GREEN   (Above Normal rainfall).   And in   quadrant   4  portions of the   Midwest  are  still wetter than Normal.



Posted by wxrisk | GENERAL,HURRICANE SEASON 2012 | Wednesday 20 June 2012 1:46 pm

1240  EDT   20   JUNE   2012

this is  great  read…