Feb 28, 2007 1300 UTC Day 1 Convective Outlook
Updated: Wed Feb 28 12:42:11 UTC 2007
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20070228 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20070228 1300 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20070228 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20070228 1300 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 281238
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0638 AM CST WED FEB 28 2007
   
   VALID 281300Z - 011200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON THROUGH TONIGHT
   OVER PARTS OF THE CENTRAL PLAINS AND MID MS VALLEY...
   
   MORNING WATER VAPOR IMAGERY SHOWS LARGE UPPER TROUGH BEGINNING TO
   AMPLIFY AND MOVE INTO PARTS OF CA/NV.  THIS TROUGH IS FORECAST TO
   BECOME A MAJOR WEATHER MAKER ACROSS MUCH OF THE NATION OVER THE NEXT
   COUPLE OF DAYS.  THE RISK OF SEVERE THUNDERSTORMS WILL BEGIN THIS
   AFTERNOON OVER PARTS OF OK/KS...AND SPREAD EASTWARD INTO THE MID MS
   VALLEY TONIGHT.
   
   ...KS/OK THIS AFTERNOON AND EVENING...
   12Z SURFACE ANALYSIS INDICATES SOUTHERLY LOW LEVEL WINDS IN PLACE
   ACROSS MOST OF THE SOUTHERN PLAINS.  GULF MOISTURE IS STREAMING
   NORTHWARD...WITH 50S DEWPOINTS NOW ACROSS MUCH OF EASTERN OK...AND
   60S AS FAR NORTH AS ACT.  VERTICAL MIXING WILL LIKELY AID IN FURTHER
   INCREASES IN DEWPOINTS BY LATE AFTERNOON AS DAYTIME HEATING RESULTS
   IN MLCAPE VALUES OF 500-1000 J/KG ALONG SURFACE DRYLINE.  PRESENT
   INDICATIONS ARE THAT MID LEVEL CAPPING INVERSION WILL SUPPRESS
   THUNDERSTORM DEVELOPMENT UNTIL LATE AFTERNOON...WITH INITIAL
   CONVECTION OCCURRING NEAR SURFACE LOW OVER SOUTH-CENTRAL
   KS/NORTH-CENTRAL OK.  THESE STORMS WILL LIKELY SPREAD NORTHEASTWARD
   INTO WESTERN MO DURING THE EVENING WITH THE RISK OF LARGE HAIL AND
   DAMAGING WINDS.  THREAT OF ISOLATED TORNADOES WILL ALSO INCREASE
   OVER SOUTHEAST KS AFTER DARK AS STRONGER VERTICAL SHEAR DEVELOPS. 
   OTHER ISOLATED CELLS COULD DEVELOP DURING THE EARLY EVENING ALONG
   THE DRYLINE OVER NORTHERN/CENTRAL OK AS LARGE SCALE FORCING
   APPROACHES...BUT CONFIDENCE IN THAT SCENARIO IS RATHER LOW AT THIS
   TIME.
   
   ...ERN OK/MO/AR OVERNIGHT...
   MID LEVEL CAP OVER THE WARM SECTOR IS EXPECTED TO RAPIDLY ERODE
   AFTER MIDNIGHT.  INCREASING FORCING FOR ASCENT WILL AID IN THE
   DEVELOPMENT OF SCATTERED THUNDERSTORMS OVER FAR EASTERN OK...
   SPREADING ACROSS SOUTHERN MO AND MUCH OF AR BY 01/12Z.  FORECAST
   SOUNDINGS IN THIS REGION SHOW VERY LARGE CURVING HODOGRAPHS WITH
   VERTICAL SHEAR PARAMETERS VERY FAVORABLE FOR SUPERCELLS AND
   TORNADOES.  MLCAPE VALUES WILL BE RATHER WEAK OVERNIGHT /GENERALLY
   BELOW 500 J/KG/.  HOWEVER...STRENGTH OF SHEAR AND APPROACHING UPPER
   TROUGH SUGGEST A POSSIBILITY OF STRONG TORNADOES...AS WELL AS HAIL
   AND DAMAGING WINDS.
   
   ...IL/KY/TN AFTER MIDNIGHT...
   STRONG LOW LEVEL WARM ADVECTION IS FORECAST TO SPREAD FAR EASTWARD
   AHEAD OF UPPER TROUGH BY THE END OF THE FORECAST PERIOD.  MODEL
   FORECAST SOUNDINGS SHOW SUFFICIENT ELEVATED CAPE AND LIFT FOR A RISK
   OF ISOLATED SEVERE STORMS PRODUCING HAIL AS FAR EAST AS WESTERN
   IL/KY/TN AND NORTHERN MS BY 01/12Z.
   
   ..HART.. 02/28/2007
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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