SPC AC 160046
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0746 PM CDT THU MAY 15 2008
VALID 160100Z - 161200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE RIO GRANDE THROUGH S
TX AREAS...
...RIO GRANDE THROUGH DEEP SOUTH TX...
THIS EVENING A COLD FRONT EXTENDS FROM THE LOWER MS VALLEY THROUGH
INTO SOUTH TX. A WEAK MOISTURE GRADIENT EXISTS ACROSS THIS BOUNDARY
WITH DEWPOINTS RANGING FROM THE UPPER 60S TO AROUND 70 IN DEEP S TX
TO THE LOWER 60S OVER THE S TX HILL COUNTRY TO SOUTH OF DEL RIO.
DIABATIC HEATING OF THE MOIST BOUNDARY LAYER HAS CONTRIBUTED TO
MODERATE INSTABILITY WITH MLCAPE FROM 1500 J/KG OVER THE RIO GRANDE
TO AROUND 3500 J/KG OVER DEEP S TX. THIS AREA REMAINS WITHIN PLUME
OF DEEP SUBTROPICAL MOISTURE AND WV IMAGERY INDICATES A SHORTWAVE
TROUGH LIFTING NNEWD THROUGH NRN MEXICO. NUMEROUS STORMS HAVE
DEVELOPED OVER THE HIGHER TERRAIN OF MEXICO...AND SOME OF THIS
ACTIVITY IS BEGINNING TO SPREAD ACROSS THE TX BORDER. WHILE LOW
LEVEL WINDS ARE WEAK...DIRECTIONAL AND BULK SHEAR REMAINS SUFFICIENT
FOR SOME SUPERCELL STRUCTURES WITH ISOLATED LARGE HAIL AND LOCALLY
DAMAGING WIND GUSTS THE MAIN THREATS...BUT AN ISOLATED TORNADO
CANNOT BE RULED OUT.
...CNTRL GA THROUGH SC...
WELL DEFINED MCV CONTINUES EWD THROUGH GA. THE 00Z ATLANTA RAOB
SHOWS STRONG LOW-MID LEVEL SHEAR WITH VERY LARGE 0-1 KM HODOGRAPHS
IN VICINITY OF THE LOW LEVEL JET AND SURFACE LOW ATTENDING THIS
FEATURE. LOW TOPPED CONVECTION CONTINUES TO TRY AND DEVELOP ACROSS
CNTRL GA IN ASSOCIATION WITH THE MCV. WILL MAINTAIN A SMALL RISK FOR
AN ISOLATED BRIEF TORNADO FROM E CNTRL GA INTO SC. HOWEVER...VERY
WEAK LAPSE RATES AND LIMITED BUOYANCY SHOULD LIMIT OVERALL SEVERE
POTENTIAL THIS EVENING.
...TN AND LOWER MS VALLEY REGIONS...
SCATTERED SHOWERS AND MULTICELL THUNDERSTORMS HAVE DEVELOPED ALONG
SEWD ADVANCING COLD FRONT FROM WRN TN SWWD THROUGH NRN MS AND SERN
AR. HOWEVER...LARGE SCALE SUBSIDENCE ALONG WITH WEAK LAPSE RATES AND
BUOYANCY IN WAKE OF SHORTWAVE TROUGH MOVING THROUGH THE TN AND OH
VALLEYS WILL LIMIT SEVERE THREAT. THIS CONVECTION SHOULD BEGIN TO
DIMINISH WITH LOSS OF HEATING.
..DIAL.. 05/16/2008
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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