Categorical Graphic
Probabilistic Tornado Graphic
Probabilistic Damaging Wind Graphic
Probabilistic Large Hail Graphic

   SPC AC 131221
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0721 AM CDT SAT JUN 13 2009
   
   VALID 131300Z - 141200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
   PARTS OF THE EASTERN TX PANHANDLE...NORTHWEST TX...AND
   WESTERN/SOUTHERN OK...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE CENTRAL AND
   SOUTHERN HIGH PLAINS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF
   MS...AL...GA...AND THE FL PANHANDLE...
   
   ...TX/OK...
   A WEAK UPPER RIDGE IS IN PLACE THIS MORNING OVER THE CENTRAL AND
   SOUTHERN PLAINS...WHILE A STRONG SHORTWAVE TROUGH MOVES ASHORE OVER
   SOUTHERN CA.  DESPITE THE RIDGE ALOFT...EASTERLY LOW LEVEL WINDS
   NORTH OF A SURFACE BOUNDARY WILL HELP TO MAINTAIN DEWPOINTS IN THE
   UPPER 60S TO NEAR 70F FROM THE EASTERN TX PANHANDLE INTO SOUTHERN OK
   AND NORTHWEST TX.  STRONG HEATING OVER MUCH OF THE AREA WILL YIELD A
   POCKET OF EXTREME INSTABILITY...WITH NUMEROUS MODELS AGREEING ON
   MLCAPE VALUES OF 4000-5000 J/KG.  HEATING WELL INTO THE 90S WILL
   SUBSTANTIALLY WEAKEN THE CAP AND LEAD TO ISOLATED THUNDERSTORMS OVER
   WEST TX AND THE EASTERN TX PANHANDLE BY LATE AFTERNOON.  THESE
   STORMS WILL BE IN A REGION OF STRONG AND INCREASING DEEP LAYER
   EFFECTIVE SHEAR /40-60 KNOTS/.  THIS WILL PROMOTE SUPERCELL
   STRUCTURES CAPABLE OF VERY LARGE HAIL AND DAMAGING WINDS.  AMPLE LOW
   LEVEL MOISTURE AND BACKED LOW LEVEL WINDS WILL ALSO POSE A RISK OF A
   FEW TORNADOES.  SLOW MOVING SUPERCELLS AND BOWING STRUCTURES ARE
   LIKELY TO PERSIST THROUGH THE EVENING AND SPREAD EASTWARD ACROSS
   SOUTHERN OK AND NORTHWEST TX.  
   
   ...NM/CO/KS...
   THE SHORTWAVE TROUGH NOW OVER SOUTHERN CA WILL BEGIN TO AFFECT
   EASTERN CO/NM BY EARLY EVENING.  MID LEVEL WINDS AND VERTICAL SHEAR
   WILL STRENGTHEN DURING THIS PERIOD...WHILE THUNDERSTORMS DEVELOP
   OVER THE MOUNTAINS OF NORTHERN NM/SOUTHERN CO.  THESE STORMS WILL
   SPREAD INTO THE ADJACENT PLAINS AND EVENTUALLY EASTWARD INTO KS. 
   INSTABILITY WILL BE WEAKER IN THIS REGION THAN FARTHER SOUTH. 
   HOWEVER...STRONGER LOW LEVEL SHEAR AND LARGE SCALE FORCING MAY
   OFFSET DRIER AND MORE STABLE CONDITIONS AND POSE A RISK OF A FEW
   SEVERE STORMS.
   
   ...MS/AL/GA/FL...
   SCATTERED THUNDERSTORMS ARE ONGOING THIS MORNING OVER PARTS OF
   MS/AL.  THIS ACTIVITY MAY INTENSIFY BY LATE MORNING/EARLY AFTERNOON
   AS DAYTIME HEATING DESTABILIZES THE AIRMASS.  ISOLATED SEVERE STORMS
   CAPABLE OF HAIL AND DAMAGING WINDS ARE EXPECTED THROUGH THE DAY AS
   STORMS SPREAD EAST-SOUTHEASTWARD TOWARD GA/FL PANHANDLE.
   
   ..HART/JEWELL.. 06/13/2009
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z