MESOSCALE DISCUSSION 0685
   NWS STORM PREDICTION CENTER NORMAN OK
   0718 AM CDT SUN MAY 03 2009
   
   AREAS AFFECTED...PORTIONS CENTRAL/ERN MS...WRN/CENTRAL AL.
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 031218Z - 031315Z
   
   BAND OF CONVECTION IS INTENSIFYING OVER CENTRAL MS AND MAY POSE
   THREAT FOR SVR GUSTS AND PERHAPS A BRIEF/QLCS-TYPE TORNADIC SPINUP.
   
   SFC MESOANALYSIS SHOWS OUTFLOW BOUNDARY FROM MCS LAST NIGHT EXTENDS
   FROM JUST N BHM...WSWWD ACROSS NRN TCL COUNTY AL...NOXUBEE COUNTY
   MS...INTERSECTING ONGOING TSTMS OVER LEAKE COUNTY MS.  RELATED
   INSTABILITY/THETAE GRADIENT MAY BE FOCUS FOR SVR POTENTIAL AS
   CENTRAL MS MCS MOVES ENEWD DURING NEXT FEW HOURS.  SFC DATA AND
   MODIFIED RUC SOUNDINGS SUGGEST THAT INFLOW LAYER AIR MASS IS
   CHARACTERIZED BY HIGH THETAE BENEATH DEEP LAYER OF NEAR SATURATION. 
   WHILE THIS WILL PREVENT CAPE FROM GETTING LARGE IN ABSENCE OF STG
   SFC HEATING...PRIND TWO ACCOMPANYING/RELATED FACTORS FAVOR SVR
   POTENTIAL EXTENDING EWD INTO AL WITH THIS ACTIVITY...
   1. NEARLY SFC-BASED EFFECTIVE INFLOW PARCELS WILL BE MAINTAINED
   ALONG AND S OF OLDER OUTFLOW BOUNDARY...WITH LESS THAN 50 J/KG
   MLCINH.
   2. 200-400 J/KG MLCAPE IN RUC SOUNDINGS N OF BOUNDARY AND UP TO 2000
   J/KG WELL S OF BOUNDARY PER JAN RAOB.
   2. INCREASING BUOYANCY FROM COMBINATION OF SUBTLE/DIURNAL SFC
   WARMING AND WAA...
   3. 45-50 KT EFFECTIVE SHEAR WITH VECTOR COMPONENT SUBSTANTIALLY
   NORMAL TO N-S PORTION OF CONVECTIVE BAND.
   
   ..EDWARDS.. 05/03/2009
   
   
   ATTN...WFO...BMX...HUN...MOB...JAN...
   
   LAT...LON   32109097 32389006 33188955 33618860 33898690 33148645
               32408704 32208832 32019021 32109097