MESOSCALE DISCUSSION 1439
   NWS STORM PREDICTION CENTER NORMAN OK
   0418 AM CDT SUN JUL 05 2009
   
   AREAS AFFECTED...PORTIONS NRN AL...SRN MIDDLE TN...NERN MS...EXTREME
   NWRN GA.
   
   CONCERNING...HEAVY RAINFALL 
   
   VALID 050918Z - 051145Z
   
   MCS AND RELATED HEAVY RAIN SUPPORTING CONDITIONS DISCUSSED IN
   EARLIER MESOSCALE DISCUSSION 1438 SHOULD SHIFT SWD ACROSS MORE OF
   NRN AL THROUGH 12Z.  SOME SEWD TRANSLATION AND WWD
   MERGING/BACKBUILDING PROCESSES COULD EXPAND MCS INTO ADJACENT
   PORTIONS GA/MS RESPECTIVELY.  AVERAGE RAIN RATES SHOULD BE LOWER
   THAN THEY WERE IN TN -- EXPECT 1-2 INCHES/HOUR WITH ISOLATED/BRIEFLY
   HIGHER RATES -- BUT STILL SUFFICIENT FOR RELATIVELY CONCENTRATED
   HEAVY RAIN THREAT GIVEN EXPECTED MERGING/TRAINING OF CELLS.
   
   ELEVATED INFLOW REGION WILL REMAIN CHARACTERIZED BY FAVORABLE LOW
   LEVEL WAA AND PW NEAR 2 INCHES...BASED ON GPS DATA AND MODEL
   SOUNDINGS.  LLJ SHOULD VEER SLIGHTLY THROUGH REMAINDER PRE-DAWN
   HOURS...AS PART OF DEEP LAYER STG MOISTURE TRANSPORT WITHIN NARROW
   E-W CORRIDOR EXTENDING FROM NRN GA BACK WWD ACROSS ARKLATEX REGION. 
   GIVEN WEAK DEEP-LAYER LAPSE RATES...BUOYANCY WILL REMAIN MRGL BUT
   STILL SUPPORTIVE...WITH MUCAPE IN 300-700 J/KG RANGE.  OVER SRN MID
   TN...STG LOW LEVEL WAA/ISENTROPIC LIFT ATOP MCS OUTFLOW POOL MAY
   CONTINUE TO GENERATE HEAVY RAIN-PRODUCING CONVECTION TO AGGRAVATE
   HAZARD FROM EARLIER ACTIVITY.  ISOLATED STG TO DAMAGING GUSTS STILL
   MAY OCCUR MAINLY OVER SRN PERIPHERY OF MCS WHERE NEAR-SURFACE
   STABILITY IS RELATIVELY MINIMIZED.
   
   MAGNITUDE OF BOTH LLJ AND RELATED MOISTURE TRANSPORT SHOULD WEAKEN
   AFTER ABOUT 11Z...WHILE LOW LEVEL FLOW ABOVE SFC ALSO BECOMES
   ALIGNED MORE PARALLEL TO CONVECTIVE PLUME.  THIS SHOULD SUPPORT NET
   WEAKENING TREND FOR REMAINDER MORNING UNTIL LATER DIURNAL HEATING
   STGLY DESTABILIZES AIR MASS S OF RESULTING BOUNDARY...AS DISCUSSED
   IN DAY-1 SVR OUTLOOK.
   
   ..EDWARDS.. 07/05/2009
   
   
   ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MEG...
   
   LAT...LON   34118699 34138863 34558842 35138778 35558761 35458631
               34638552 34288512 33828609 34118699