MESOSCALE DISCUSSION 0494
   NWS STORM PREDICTION CENTER NORMAN OK
   1133 AM CDT SAT MAR 29 2008
   
   AREAS AFFECTED...PARTS OF ERN TX...LA...MS
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 291633Z - 291830Z
   
   A GRADUAL INCREASE IN THUNDERSTORM ACTIVITY APPEARS PROBABLE THROUGH
   MID AFTERNOON AND BEYOND.  ALTHOUGH ISOLATED CELLS COULD APPROACH OR
   BRIEFLY EXCEED SEVERE CRITERIA...SEVERE POTENTIAL GENERALLY APPEARS
   LOW.  HOWEVER...TRENDS WILL BE MONITORED.
   
   AN IMPULSE EMANATING FROM A WEAK SUBTROPICAL BELT OF WESTERLIES
   CONTINUES TO SLOWLY PROGRESS ACROSS THE LOWER MISSISSIPPI VALLEY. 
   THIS IS ACCOMPANIED BY A DISCERNIBLE LOW/MID-LEVEL CIRCULATION
   ...WHICH IS EXPECTED TO SHIFT OUT OF NORTHEAST LOUISIANA...NEAR THE
   INTERSTATE 20 CORRIDOR...THROUGH CENTRAL MISSISSIPPI BETWEEN NOW AND
   20-21Z.  ASSOCIATED FORCING FOR UPWARD VERTICAL MOTION IS EXPECTED
   TO CONTRIBUTE TO CONVECTIVE DEVELOPMENT...AS A MOIST BOUNDARY LAYER
   ACROSS UPPER TEXAS COASTAL AREAS...CENTRAL/SOUTHERN LOUISIANA AND
   MISSISSIPPI WARMS WITH DAYTIME HEATING.  
   
   DEVELOPMENT WILL PROBABLY NOT BE PARTICULARLY RAPID...BUT MIXED
   LAYER CAPE INCREASING TO AROUND 1000 J/KG BY 19-21Z SHOULD BECOME
   SUPPORTIVE OF STEADILY INTENSIFYING STORMS.  A STALLED SURFACE FRONT
   MAY PROVIDE THE FOCUS FOR ACTIVITY...BOTH AHEAD OF THE CYCLONIC
   VORTICITY CENTER...NEAR/EAST AND SOUTH OF JACKSON MS...AND IN THE
   LOW/MID-LEVEL WARM ADVECTION REGIME TO ITS WAKE...NEAR/WEST AND
   NORTH OF ALEXANDRIA LA.
   
   LOW-LEVEL HODOGRAPHS ACROSS THIS REGION ARE WEAK...BUT 30-40 KT
   WESTERLY 500 MB FLOW...AND MODERATELY STEEP MID-LEVEL LAPSE RATES
   COULD SUPPORT A FEW RELATIVELY SHORT-LIVED STRONGER CELLS CAPABLE OF
   PRODUCING HAIL/LOCALIZED WIND GUSTS NEAR SEVERE LIMITS. 
   OTHERWISE...SEASONABLY HIGH MOISTURE LEVELS...WITH PRECIPITABLE
   WATER VALUES IN EXCESS OF 1.5 INCHES...MAY SUPPORT LOCALLY HEAVY
   RAINFALL IN SLOW MOVING/TRAINING STORM CLUSTERS LATER THIS
   AFTERNOON.
   
   ..KERR.. 03/29/2008
   
   
   ATTN...WFO...MOB...JAN...LIX...LCH...SHV...
   
   32419445 32389330 31969246 31989167 32509075 33138990
   32948861 31918832 31018891 30719000 30439102 30349206
   30769339 30929408 31659472 32139481