MESOSCALE DISCUSSION 0692
   NWS STORM PREDICTION CENTER NORMAN OK
   0130 AM CDT MON MAY 04 2009
   
   AREAS AFFECTED...PORTIONS SRN MS...SRN AL...SWRN/W-CENTRAL GA.
   
   CONCERNING...HEAVY RAINFALL 
   
   VALID 040630Z - 040930Z
   
   CONVECTIVE COVERAGE IS FCST TO INCREASE IN ZONAL BAND FROM
   SWRN/S-CENTRAL MS EWD ACROSS SRN AL DURING NEXT FEW HOURS...N OF
   OUTFLOW BOUNDARY FROM DERECHO-PRODUCING MCS OF YESTERDAY. 
   EMBEDDED/TRAINING TSTMS WILL CONTAIN RAIN RATES 1.5-2.5 INCHES/HOUR.
   
   SFC MESOANALYSIS INDICATES OUTFLOW BOUNDARY QUASISTATIONARY NEAR
   THIS LINE -- AGS...ABY...CEW...MOB...20 SE BTR.  BOUNDARY MAY DRIFT
   NWD OVER COASTAL PLAIN.  DIFFUSE COLD FRONT OVER ERN TN...NRN AL AND
   CENTRAL MS SHOULD REMAIN ILL-DEFINED WITHIN MASSIVE OUTFLOW POOL.
   MOST CONVECTION WILL REMAIN BETWEEN THESE BOUNDARIES...ASSOCIATED
   WITH STG LOW LEVEL WAA REGIME ATOP SHALLOW SLOPE OF OUTFLOW
   AIR...AND INVOF 35-50 KT LLJ.  PARCELS WILL BE LIFTED ISENTROPICALLY
   TO LFC AMIDST VERY MOIST ELEVATED INFLOW PARCELS...WITH 850 MB DEW
   POINTS 11-13 C AND UPSTREAM GPS PW MEASURED IN 1.4-1.7 INCH RANGE. 
   FCST GRADUAL VEERING OF LLJ SHOULD SHIFT ZONE OF STRONGEST MOISTURE
   TRANSPORT AND WAA EWD ACROSS THIS REGION...WHILE 700-500 LAYER UVV
   MAX NOW OVER SRN MS DOES LIKEWISE.  ELEVATED MUCAPE SHOULD INCREASE
   TO 1000-1500 J/KG RANGE  AS WAA DESTABILIZES SRN LOBE OF
   CONVECTIVELY OVERTURNED AIR MASS ABOVE SFC.
   
   ALTHOUGH PRIMARY HAZARD WILL BE FROM HEAVY RAINFALL...SUFFICIENT
   DEEP-LAYER SHEAR EXISTS TO SUPPORT ELEVATED STORM ROTATION AND
   ISOLATED HAIL...WITH EFFECTIVE SHEAR MAGNITUDE 40-45 KT.  WIND
   POTENTIAL WILL BE MITIGATED BY STABLE LAYER NEAR SFC...THOUGH STG
   GUSTS ARE POSSIBLE WITH ANY ACTIVITY THAT CAN ORGANIZE INTO LINE
   SEGMENTS PERPENDICULAR TO PREVAILING WLYS ALOFT.  AREA WILL BE
   MONITORED FOR MORE SFC-BASED SUPERCELL POTENTIAL IF BOUNDARY CAN
   LIFT CLOSER TO SRN EDGE OF CONVECTIVE PLUME.
   
   ..EDWARDS.. 05/04/2009
   
   
   ATTN...WFO...FFC...TAE...BMX...MOB...JAN...LIX...
   
   LAT...LON   31198606 31218988 31099136 31878981 32598504 32758400
               31788408 31198606