Apr 13, 2007 0600 UTC Day 1 Convective Outlook
Updated: Fri Apr 13 10:06:14 UTC 2007
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Public Severe Weather Outlook

The SPC is forecasting ...severe thunderstorms expected over parts of the southern plains later today and tonight....   Please read the latest public statement about this event.

Categorical Graphic
20070413 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20070413 1200 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20070413 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20070413 1200 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 130557
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1257 AM CDT FRI APR 13 2007
   
   VALID 131200Z - 141200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF CNTRL THROUGH NERN
   TX INTO THE LOWER MS VALLEY...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN PLAINS INTO THE
   LOWER MS VALLEY...
   
   ...SYNOPSIS...
   
   SHORTWAVE TROUGH CURRENTLY OVER THE SWRN U.S. WILL ADVANCE EAST INTO
   THE SRN PLAINS FRIDAY AFTERNOON. ATTENDANT LEE SURFACE LOW AND COLD
   FRONT WILL SHIFT EAST THROUGH TX WHILE WARM FRONT LIFTS NWD TO NEAR
   THE RED RIVER AREA BY EARLY FRIDAY EVENING.
   
   
   ...CNTRL AND ERN TX THROUGH LOWER MS VALLEY...
   
   LATEST OBSERVATIONS AND THE 00Z RAOB DATA SHOW RICH BOUNDARY LAYER
   MOISTURE OVER S TX WITH DEWPOINTS AROUND 70. STRONG SLY LOW LEVEL
   JET WILL PERSIST IN ADVANCE OF THE APPROACHING SHORTWAVE TROUGH AND
   CONTRIBUTE TO THETA-E ADVECTION THROUGH CNTRL AND ERN TX FRIDAY IN
   WAKE OF RETREATING WARM FRONT. SOME LOW CLOUDS MAY ACCOMPANY THE
   INITIAL MOISTURE SURGE. HOWEVER...UPPER 60S DEWPOINTS RETURNING NWD
   BENEATH STEEP MID LEVEL LAPSE RATES SHOULD CONTRIBUTE TO MODERATE
   INSTABILITY WITH MLCAPE FROM 1500 TO 2000 J/KG. STORMS WILL LIKELY
   BE ONGOING EARLY FRIDAY...MOSTLY WITHIN ZONE OF WARM ADVECTION AND
   ISENTROPIC LIFT N OF WARM FRONT FROM PARTS OF N TX INTO OK AND KS.
   THIS ACTIVITY SHOULD BE ELEVATED WITH A THREAT FOR MAINLY HAIL.
   
   STORMS SHOULD GRADUALLY DEVELOP SWD INTO THE PRE-FRONTAL WARM SECTOR
   ALONG WARM CONVEYOR BELT AS THE ATMOSPHERE DESTABILIZES AND AS UPPER
   DIVERGENCE AND FORCING FOR ASCENT INCREASES WITH THE APPROACH OF THE
   UPPER TROUGH. A STRONG 50+ KT LOW LEVEL JET WILL PERSIST OVER CNTRL
   AND ERN TX WITHIN EXIT REGION OF CYCLONICALLY CURVED UPPER JET. THIS
   WILL RESULT IN FAVORABLE LOW LEVEL HODOGRAPHS AND DEEP LAYER SHEAR
   FOR ORGANIZED STORM STRUCTURES INCLUDING SUPERCELLS AND BOW ECHOES
   CAPABLE OF PRODUCING A FEW TORNADOES...VERY LARGE HAIL AND DAMAGING
   WIND. GIVEN THE EXPECTED COMBINATION OF LOW-MID LEVEL SHEAR AND CAPE
   ISOLATED STRONG TORNADOES WILL BE POSSIBLE...ESPECIALLY WITH ANY
   DISCRETE SUPERCELL MODES. ACTIVITY WILL SHIFT EAST INTO THE LOWER MS
   VALLEY FRIDAY EVENING WITH A CONTINUED SEVERE THREAT.
   
   ...NWRN TX INTO SWRN OK...
   
   MUCH OF THE STORMS IN OK ARE EXPECTED TO REMAIN ELEVATED N OF WARM
   FRONT WITH A THREAT FOR MAINLY HAIL. HOWEVER...MODELS SUGGEST MID
   LEVEL DRY SLOT COULD ADVANCE NEWD INTO NWRN TX AND PARTS OF SWRN OK
   DURING THE AFTERNOON...AND THIS WILL INCREASE THE CHANCES FOR LOW
   CLOUDS TO MIX OUT. IF LOW CLOUDS CAN MIX OUT...SURFACE HEATING  AND
   COLD MID LEVEL PROFILES SHOULD RESULT IN AT LEAST MARGINAL SURFACE
   BASED INSTABILITY IN A RELATIVELY NARROW CORRIDOR. ADDITIONAL STORMS
   MAY DEVELOP WITHIN ZONE OF DPVA NEAR TRIPLE POINT OR SWD ALONG COLD
   FRONT AND ADVANCE EAST. A CONDITIONAL THREAT WILL EXIST FOR DAMAGING
   WIND...LARGE HAIL AND POSSIBLY AN ISOLATED TORNADO OR TWO.
   
   ..DIAL/CROSBY.. 04/13/2007
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z