Sep 21, 2009 1300 UTC Day 1 Convective Outlook
Updated: Mon Sep 21 12:30:18 UTC 2009
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20090921 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20090921 1300 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20090921 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20090921 1300 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 211226
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0726 AM CDT MON SEP 21 2009
   
   VALID 211300Z - 221200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE SRN AND
   CENTRAL PLAINS...
   
   ...SRN/CENTRAL PLAINS...
   INTENSE...EARLY FALL UPPER LOW WILL CONTINUE TO EVOLVE OVER THE
   CENTRAL HIGH PLAINS REGION THROUGH TONIGHT AS STRONGEST ENERGY DIGS
   SYSTEM SSWWD.  ASSOCIATED SURFACE COLD FRONT EXTENDED FROM THE ND/MN
   BORDER SWD INTO N-CENTRAL KS AND SWWD INTO THE OK/NRN TX PANHANDLE
   AND NERN CO AT DAYBREAK.  THIS FRONT WILL CONTINUE SURGING ESEWD
   THROUGH THE DAY...OUTRUNNING STRONGEST MID LEVEL WINDS AND RESULTANT
   DEEP LAYER SHEAR REMAINING ATOP POST-FRONTAL AIR MASS. 
   
   BANDS OF ELEVATED THUNDERSTORMS WILL PERSIST THIS MORNING INTO THE
   AFTERNOON AHEAD OF THE FRONT FROM NRN OK/SRN KS INTO IA/WRN MO
   WITHIN BROAD LOW LEVEL WAA REGIME.  GIVEN RELATIVELY STEEP MID LEVEL
   LAPSE RATES EVIDENT ON 12Z SOUNDINGS...A FEW STRONGER CORES REMAIN
   POSSIBLE WITH POTENTIAL FOR ISOLATED LARGE HAIL.  HOWEVER...ONLY
   MODEST DEEP LAYER SHEAR WILL LIMIT UPDRAFT/ORGANIZATION OF THE
   STRONGER CORES ACROSS THIS REGION AND SURFACE-BASED POTENTIAL WILL
   BE LIMITED BY EARLY DAY CLOUDS/PRECIPITATION AHEAD OF THE SURFACE
   COLD FRONT.  FARTHER SW...MODERATE INSTABILITY CAN BE EXPECTED AS
   AFTERNOON HEATING INTO/THROUGH THE 80S F OCCURS WITHIN AXIS OF MID
   60S-LOWER 70S F SURFACE DEW POINTS FROM PORTIONS NWRN/N-CENTRAL TX
   INTO THE NERN OK AND VICINITY.  EXPECT INCREASING TSTMS ACROSS THIS
   REGION THROUGH THE AFTERNOON WITHIN ZONE BOTH AHEAD OF AND JUST
   BEHIND SHALLOW SURFACE COLD FRONT.  ALTHOUGH FORECAST SOUNDINGS
   SUGGEST EFFECTIVE SHEAR WILL REMAIN IN THE 20-30 KT RANGE FOR THE
   MOST PART...STEEP LAPSE RATES AND MLCAPE TO 2000 J/KG SHOULD SUPPORT
   POTENTIAL FOR ORGANIZED MULTICELL/BRIEF-SUPERCELLS WITH PRIMARY
   THREAT OF LARGE HAIL AND ISOLATED DAMAGING WINDS.  
   
   ...CENTRAL-SRN HIGH PLAINS...
   INTENSE UPPER LOW AND ASSOCIATED MID LEVEL COLD POCKET /I.E. H5
   TEMPS TO -22C/ WILL SHIFT SWD ACROSS CO TODAY AND LIKELY SUPPORT
   DEVELOPMENT OF WEAK INSTABILITY INTO NERN NM/FAR SRN CO THIS
   AFTERNOON...DESPITE INFLUX OF COOLER/STABLE POST-FRONTAL SURFACE
   AIR.  THIS SHOULD SUPPORT SCATTERED TSTM DEVELOPMENT OVER HIGHER
   TERRAIN FROM CO INTO NRN/CENTRAL NM WITH POTENTIAL FOR HAIL WITH THE
   STRONGER CORES SHIFTING ESEWD OVER LOWER ELEVATIONS LATER TODAY/THIS
   EVENING.
   
   ..EVANS/JEWELL.. 09/21/2009
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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