MESOSCALE DISCUSSION 0367

MESOSCALE DISCUSSION 0367

   NWS STORM PREDICTION CENTER NORMAN OK

   0358 PM CDT TUE MAR 27 2012

  

   AREAS AFFECTED...EASTERN IA/SOUTHERN WI/NORTHWEST IL/NORTHEAST MO

  

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

  

   VALID 272058Z - 272300Z

  

   MONITORING FOR AN INCREASING SEVERE THREAT...WHICH COULD INITIALLY

   OCCUR ACROSS PORTIONS OF THE REGION INTO THE 23Z-02Z TIME FRAME. A

   WATCH MAY BE NEEDED THIS EVENING.

  

   A WEAK COLD FRONT CONTINUES TO MAKE A GRADUAL EASTWARD PROGRESSION

   TOWARD THE UPPER MS RIVER VALLEY AT MID AFTERNOON WITHIN A

   NORTHEAST-SOUTHWEST ORIENTED CORRIDOR FROM WESTERN WI TO

   SOUTH-CENTRAL IA/NORTHWEST MO. MODEST LOW-LEVEL MOISTURE...WITH

   SURFACE DEWPOINTS GENERALLY IN THE 50S F...OTHERWISE CONTINUES TO

   STEADILY INCREASE WITH NORTH-NORTHEASTWARD EXTENT IMMEDIATELY AHEAD

   OF THE FRONT. NEAR/AHEAD OF THIS FRONT...LOW-LEVEL CONVERGENCE

   REMAINS MODEST AS WINDS AT/JUST ABOVE THE SURFACE HAVE CONTINUED TO

   VEER PER SURFACE OBSERVATIONS/REGIONAL DERIVED WIND DATA.

   HOWEVER...A LOW-AMPLITUDE EASTWARD-MOVING SHORTWAVE TROUGH/SPEED MAX

   CURRENTLY OVER SD/SOUTHWEST MN PER WATER VAPOR IMAGERY MAY PROVIDE

   AN IMPETUS FOR AT LEAST ISOLATED DEEP CONVECTIVE DEVELOPMENT OVER

   THE NEXT FEW HOURS...AS INHIBITION OTHERWISE CONTINUES TO ERODE

   WITHIN THE MODESTLY MOIST NEAR-FRONTAL WARM SECTOR.

  

   WHILE CONFIDENCE IN CONVECTIVE DETAILS ARE NOT PARTICULARLY

   HIGH...AN ASSORTMENT OF NUMERICAL GUIDANCE INCLUDING A NUMBER OF 15Z

   SREF MEMBERS IMPLY THAT SUCH DEVELOPMENT WILL BE MORE PROBABLE INTO

   THE 23Z-02Z TIME FRAME ESPECIALLY ACROSS FAR EASTERN IA/FAR

   NORTHWEST IL AND ADJACENT PARTS OF NORTHERN MO...ALTHOUGH A GRADUAL

   DEEPENING OF THE CUMULUS FIELD HAS BEEN NOTED AS FAR NORTHEAST AS

   SOUTHWEST WI AT MID-AFTERNOON. IF/WHERE DEEP CONVECTIVE DEVELOPMENT

   DOES OCCUR INTO THIS EVENING...STRONG EFFECTIVE SHEAR /45-50 KT OR

   GREATER/ WILL SUPPORT ORGANIZED/SUSTAINED STORMS INCLUDING INITIAL

   MODE SUPERCELLS CAPABLE OF SEVERE HAIL/PERHAPS A TORNADO...WITH

   DAMAGING WINDS A POSSIBILITY AS WELL. CONVECTIVE TRENDS WILL

   CONTINUE TO BE MONITORED FOR A POSSIBLE WATCH.

  

   ..GUYER.. 03/27/2012

  

  

   ATTN...WFO...LOT...MKX...DVN...ARX...DMX...