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

   SPC AC 041626
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1126 AM CDT FRI MAY 04 2007
   
   VALID 041630Z - 051200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EARLY TONIGHT
   OVER PARTS OF EASTERN CO...WESTERN AND CENTRAL KS...NORTHWEST OK AND
   SOUTHWEST NEB...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM SOUTHWEST TX INTO SD...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PARTS OF LOWER MS VALLEY...
   
   ...CENTRAL/SRN HIGH PLAINS...
   
   MAJOR COLD TROUGH CONTINUES TO DIG INTO INTERIOR OF THE WESTERN U.S.
   LEADING TO CLOSED UPPER LOW VICINITY 4-CORNERS BY 12Z SAT. BAND OF
   VERY STRONG WINDS ON BACK SIDE OF TROUGH INITIALLY WILL ROTATE
   ACROSS SRN ROCKIES THIS AFTERNOON/EVENING. THIS LEADS TO INCREASING
   UPPER DIFFLUENCE SPREADING ACROSS HIGH PLAINS BEGINNING LATE THIS
   AFTERNOON.
   
   COLD FRONT HAS PUSHED EWD ACROSS DAKOTAS...WRN NEB EXTENDING SWWD
   INTO SERN CO. SURFACE LOW SWRN CORNER OF KS WITH DRY LINE EXTENDING
   THRU ERN TX PANHANDLE TO SWRN TX. SURFACE PRESSURE/UPPER HEIGHT
   FALLS IN ADVANCE OF WRN TROUGH WILL RESULT IN DEEPENING OF SURFACE
   LOW ALONG SERN CO/KS BORDER DURING AFTERNOON...THEN MOVING SLOWLY
   NWD TONIGHT.
   
   INCREASING SLY FLOW E OF DRY LINE IS RAPIDLY INCREASING LOW LEVEL
   MOISTURE NWD INTO CENTRAL PLAINS LEADING TO A VERY UNSTABLE AIR MASS
   BY MID AFTERNOON FROM WRN TX TO WRN KS.  MLCAPES AOA 4000 J/KG WILL
   BE IN PLACE BY LATER THIS AFTERNOON E OF DRY LINE NWD INTO WRN KS.
   
   50-60KT OF DEEP LAYER SHEAR COUPLED WITH ELY LOW LEVEL FLOW N OF
   SURFACE LOW SUPPORTS RAPID DEVELOPMENT OF SUPERCELLS IN UPSLOPE AREA
   OF ERN CO BY MID AFTERNOON. MORE LIMITED INSTABILITY THIS AREA THAN
   E OF DRY LINE...HOWEVER GIVEN SHEAR AND STEEP LAPSE RATES...LARGE
   HAIL AND A FEW TORNADOES EXPECTED AS STORMS MOVE/DEVELOP NEWD TOWARD
   CO/KS BORDER THIS EVENING.
   
   THE INTERSECTION OF DRY LINE/COLD FRONT OVER WRN KS FOCUSES ANOTHER
   AREA OF ENHANCED CONVERGENCE AND CONVECTIVE INITIATION BY MID/LATE
   AFTERNOON.  WITH THE HIGH INSTABILITY AND ENHANCED VEERING SHEAR
   PROFILES VICINITY  FRONTAL ZONE/DRY LINE...SUPERCELLS WOULD RAPIDLY
   BECOME SEVERE WITH VERY LARGE HAIL AND TORNADO POTENTIAL.  STRONG
   TORNADOES CERTAINLY A POSSIBILITY IN WRN KS GIVEN THE HIGH
   CAPE/SHEAR ENVIRONMENT EXPECTED TO BE IN PLACE BY LATE AFTERNOON.
   
   FURTHER SOUTH ALONG DRY LINE FROM SRN KS ALONG TX/OK BORDER INTO
   SWRN TX...THE THREAT OF STORM INITIATION WILL BE BOTH MORE
   CONDITIONAL AND LATER.  BY EVENING WITH CAP WEAKENING AND INCREASING
   UPPER DIFFLUENCE AHEAD OF APPROACHING WIND MAX...AT LEAST ISOLATED
   INITIATION IS LIKELY VICINITY/JUST E OF DRY LINE.  WITH MLCAPES AOA
   4000 J/KG...STORMS THAT AREA ABLE TO FORM WILL QUICKLY BECOME
   SEVERE/SUPERCELLS WITH LARGE HAIL AND TORNADO THREAT.
   
   AFTER 00Z SEVERE THUNDERSTORMS WILL LIKELY CONTINUE AND BECOME MORE
   WIDESPREAD AS THEY SPREAD NEWD ACROSS CENTRAL PLAINS AS FAR N AS SRN
   SD.  THIS SUPPORTED BY CONTINUED DEEPENING OF SURFACE LOW NEWD THRU
   CENTRAL HIGH PLAINS AS S/WV IMPULSE ROTATES NEWD FROM SRN ROCKIES.
   
   ...LOWER MS VALLEY...
   SCATTERED STRONG/ISOLATED SEVERE THUNDERSTORMS ARE ONGOING OVER SRN
   LA/MS.  THESE STORMS ARE OCCURRING IN A VERY MOIST/MODERATELY
   UNSTABLE AND WEAKLY CAPPED ENVIRONMENT.  DURING AFTERNOON  SHEAR
   WEAKENS AS UPPER TROUGH LWR MS VALLEY ROTATES NEWD AWAY FROM AREA. 
   THIS SHOULD LIMIT SEVERE THREAT TO BRIEF WET DOWNBURSTS AND ISOLATED
   LARGE HAIL...DIMINISHING BY EVENING.
   
   ..HALES/GUYER.. 05/04/2007
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z