SPC AC 230917
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0417 AM CDT FRI APR 23 2004
   
   VALID 251200Z - 261200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OH VALLEY SWWD TO LOWER MS
   VALLEY...
   
   OH VALLEY SWWD TO LOWER MS VALLEY
   
   LARGE SCALE TROUGH DEEPENS SEWD ACROSS WRN GREAT LAKES ON SUNDAY
   EFFECTIVELY ABSORBING THE CURRENT S/WV OVER 4-CORNERS AS IT EJECTS
   RAPIDLY NEWD DURING WEEKEND. MODELS ARE IN SOME DISAGREEMENT ON
   TRACK AND SPEED OF ASSOCIATED SURFACE LOW...BUT THE 06Z ETA TAKING
   IT ACROSS LOWER MI SUNDAY AFTERNOON IS THE PREFERRED SOLUTION ATTM.
   
   MOST ACTIVE PORTION OF COLD FRONT TRAILING SWWD FROM LOW WILL CROSS
   OH VALLEY DURING THE DAY WITH SRN PORTION OF FRONT MOVING MORE
   SLOWLY SEWD ACROSS LOWER MS VALLEY TO S TX.
   
   LOW LEVEL MOISTURE WILL SURGE NEWD AHEAD OF FRONT THROUGH TN/OH
   VALLEYS IN ADVANCE OF COLD FRONT. POTENTIAL FOR MDT INSTABILITY
   DEVELOPING BY MID DAY AS CAP WEAKENS RATHER QUICKLY GIVEN THE MID
   LEVEL COLD ADVECTION WITH DEEPENING TROUGH ALONG WITH LARGE SCALE
   ASCENT IN ENTRANCE REGION OF STRONG POLAR JET MAX NRN GREAT LAKES.
   
   STRONG COUPLED JET TRAVERSES OH VALLEY DURING THE AFTERNOON WITH 850
   MB WINDS 40-50 KT AND 500 MB WINDS OF 60-70 KT.  ETA POINT MODEL
   SOUNDINGS... GIVEN THE POTENTIAL FOR MUCAPES OF 1500 J/KG ARE
   FAVORABLE FOR SUPERCELL DEVELOPMENT IN THE WARM SECTOR ACROSS OH
   VALLEY SUNDAY AFTERNOON.  SFC-6 KM SHEAR OF 50-60KT AND LOW LEVEL
   SFC-1KM HELICITY OF 200-300 M2/S2 ALONG WITH LCLS AROUND 1KM WOULD
   ADDITIONALLY SUGGEST THAT TORNADIC SUPERCELLS WOULD BE POSSIBLE.
   
   AT THIS TIME TOO EARLY TO HIGHLIGHT A SIGNIFICANT THREAT OF
   SEVERE...HOWEVER IF THE FORECASTED INSTABILITY CAN DEVELOP THEN
   SUNDAY AFTERNOON COULD BE QUITE ACTIVE E OF COLD FRONT IN THE OH
   VALLEY.
   
   AHEAD OF THE COLD FRONT THE SHEAR AND UPPER SUPPORT IS WEAKER S OF
   OH VALLEY...HOWEVER WITH THE POTENTIAL FOR MDT/STG INSTABILITY...A
   SLIGHT RISK OF SEVERE THUNDERSTORM EXTENDS AT LEAST AS FAR S AS NRN
   PORTIONS OF LOWER MS VALLEY.
   
   ..HALES.. 04/23/2004
   
   ...NOTICE...
   FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
   LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
   GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
   HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
   INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
   
   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED FOR 1200Z