May 7, 2008 1300 UTC Day 1 Convective Outlook
Updated: Wed May 7 13:01:13 UTC 2008
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20080507 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20080507 1300 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20080507 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20080507 1300 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 071257
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0757 AM CDT WED MAY 07 2008
   
   VALID 071300Z - 081200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS TODAY THROUGH TONIGHT FOR PARTS
   OF THE SRN PLAINS TO THE LOWER MS VALLEY...
   
   ...SRN PLAINS TO PARTS OF THE LOWER MS VALLEY THROUGH TONIGHT...
   A STRONG MID LEVEL SHORTWAVE TROUGH OVER SE NM/W TX THIS MORNING
   WILL EJECT ENEWD TO THE RED RIVER VALLEY BY LATE AFTERNOON...AND
   THEN CONTINUE OVER AR TONIGHT.  THIS MID LEVEL TROUGH WILL BE
   ACCOMPANIED BY A SURFACE CYCLONE WHICH WILL DEVELOP ENEWD FROM NW TX
   TO NW AR BY THE END OF THE PERIOD.  A 70-80 KT SSWLY MID LEVEL JET
   AND ASSOCIATED 50 KT LLJ WILL PRECEDE THE MID LEVEL WAVE TODAY INTO
   TONIGHT ACROSS TX/OK/LA/AR.
   
   WIDESPREAD OVERNIGHT CONVECTION HAS MUDDLED THE SURFACE PATTERN THIS
   MORNING AND APPEARS TO HAVE REDUCED THE POTENTIAL FOR SEVERE STORMS
   ACROSS NW TX AND WRN/NRN OK.  INSTEAD...THE GREATER SEVERE STORM
   THREAT WILL SHIFT EWD TO NEAR AND E OF I-35/I-44 IN S CENTRAL/SE OK
   AND N CENTRAL/NE TX THIS AFTERNOON...IMMEDIATELY IN ADVANCE OF THE
   SURFACE CYCLONE AND OUTSIDE THE AREAS OVERTURNED BY WIDESPREAD
   CONVECTION THIS MORNING.  IT APPEARS THERE WILL BE A NARROW CORRIDOR
   ACROSS N/NE TX INTO SE OK THIS AFTERNOON WHERE THE STEEPER MID LEVEL
   LAPSE RATES OVERLAP THE LOW-LEVEL MOISTURE AXIS...ON THE W SIDE OF
   THE STRONGER LOW-LEVEL SHEAR.  CONVECTIVE INITIATION SHOULD BE
   FOCUSED NEAR AND JUST E OF THE SURFACE LOW NEAR THE RED RIVER
   TODAY...AND ALONG THE TRAILING DRYLINE THIS AFTERNOON INTO N/NE TX. 
   FORECAST SOUNDINGS IN THIS AREA ARE SUPPORTIVE OF SUPERCELLS CAPABLE
   OF PRODUCING LARGE HAIL...DAMAGING WINDS...AND A FEW TORNADOES.  A
   POTENTIAL LIMITING FACTOR TODAY WILL BE CLOUDS REDUCING SURFACE
   HEATING ACROSS THE RED RIVER VALLEY.
   
   STRONG LOW-LEVEL FLOW AND SHEAR ARE EXPECTED THIS AFTERNOON FROM NRN
   LA INTO AR.  HOWEVER...SATELLITE DERIVED PRECIPITABLE WATER
   ESTIMATES AND OBSERVED SOUNDINGS HAVE SHOWN SUBSTANTIAL DRYING ABOVE
   THE SURFACE ACROSS THE NW GULF REGION.  SOME OF THE DRY AIR WILL
   LIKELY MIX DOWN INTO THE BOUNDARY LAYER THIS AFTERNOON AND REDUCE
   DEWPOINTS/SURFACE-BASED INSTABILITY ACROSS LA/AR...LEAVING A NARROW
   INSTABILITY CORRIDOR ALONG THE DRYLINE ACROSS OK/TX.  LOW-LEVEL
   MOISTURE WILL BE MORE SHELTERED FROM MIXING ACROSS SRN/SERN
   MO...THOUGH CLOUDS/COOLER SURFACE TEMPERATURES WILL TEND TO LIMIT
   DESTABILIZATION SOMEWHAT.  FINALLY...LOW-LEVEL MOISTURE MAY RECOVER
   SOME OVERNIGHT INTO THE LA/AR AREA AS THE SYNOPTIC SYSTEM MOVES EWD
   INTO AR AND VERTICAL SHEAR REMAINS STRONG.  THERE WILL BE SOME
   THREAT FOR DAMAGING WINDS AND AN ISOLATED TORNADO OR TWO...THOUGH
   CONVECTIVE COVERAGE/MODE ARE IN QUESTION LATE TONIGHT AND RELATIVELY
   LOWER PROBABILITIES ARE WARRANTED COMPARED TO AREAS FARTHER W THIS
   AFTERNOON/EVENING.
   
   ..THOMPSON/GRAMS.. 05/07/2008
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z