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

   SPC AC 021628
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1128 AM CDT FRI MAY 02 2008
   
   VALID 021630Z - 031200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
   ACROSS ERN AR...NRN LA...WRN TN AND NWRN MS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN GREAT LAKES SWD
   INTO THE LOWER MS VALLEY...
   
   ...SYNOPSIS...
   
   CLOSED UPPER LOW OVER THE CNTRL PLAINS THIS MORNING IS FORECAST TO
   GRADUALLY EVOLVE INTO AN OPEN WAVE AS ATTENDANT 90-100 KT MIDLEVEL
   JET STREAK ROTATES THROUGH THE TROUGH BASE THROUGH THE MID MS VALLEY
   AND INTO THE UPPER GREAT LAKES.  AS THIS OCCURS...THE ZONE OF
   STRONGEST HEIGHT FALLS/DYNAMIC FORCING FOR ASCENT WILL BE FOCUSED
   ACROSS THE MIDWEST INTO UPPER GREAT LAKES.  FARTHER S...STRONGLY
   DIFFLUENT REGION BETWEEN CYCLONIC POLAR JET STREAK AND ANTICYCLONIC
   SUBTROPICAL JET STREAK FROM NRN MEXICO INTO THE GULF OF MEXICO
   SHOULD MAINTAIN A BROAD ZONE OF ASCENT OVER THE LOWER MS VALLEY AND
   MID SOUTH.
   
   IN THE LOW-LEVELS...OCCLUDING SURFACE LOW OVER SWRN IA THIS MORNING
   IS FORECAST TO DEVELOP NNEWD INTO SERN MN BY LATE AFTERNOON OR EARLY
   EVENING AND INTO NRN WI OR THE WRN UP OF MI BY SATURDAY MORNING. 
   ASSOCIATED...TRAILING COLD FRONT WILL PUSH EWD THROUGH THE MS
   VALLEY...LIKELY EXTENDING FROM MI SWWD INTO THE LOWER MS VALLEY BY
   THE END OF THE PERIOD.
   
   ...LOWER MS VALLEY...
   
   12Z REGIONAL SOUNDINGS INDICATE A MOIST PRE-FRONTAL AIR MASS
   /DEWPOINTS OF 65-70F/ BENEATH A PLUME OF STEEP MIDLEVEL LAPSE RATES
   /EML/ ORIGINATING OVER THE SRN PLATEAU REGION.  VISIBLE SATELLITE
   IMAGERY SUGGESTS THAT BREAKS IN THE CLOUDS SHOULD ALLOW FOR
   RELATIVELY STRONG DIABATIC HEATING WITH AIR MASS BECOMING MODERATELY
   UNSTABLE BY AFTERNOON WITH MLCAPES APPROACHING 1500-2500 J/KG.
   
   NOCTURNAL...QUASI-LINEAR CONVECTIVE SYSTEM /QLCS/ REMAINS CLOSELY
   TIED TO SYNOPTIC-SCALE COLD FRONT FROM AR SWWD INTO ERN TX.  THIS
   SYSTEM WILL LIKELY REINTENSIFY TODAY AS FRONT PROGRESSES EWD AND
   ENCOUNTERS MODERATELY UNSTABLE AIR MASS.  ADDITIONAL...MORE DISCRETE
   STORM DEVELOPMENT WILL ALSO BE POSSIBLE ALONG OUTFLOW BOUNDARY OR
   GRAVITY WAVE WHICH HAS PROPAGATED AHEAD OF QLCS...EXTENDING FROM THE
   MS DELTA REGION SWWD INTO NERN LA AS OF 1530Z.
   
   AREA VWPS/PROFILERS AND LATEST MODEL GUIDANCE SUGGESTS THAT
   LOW-LEVEL SHEAR WILL REMAIN RATHER STRONG ACROSS WARM SECTOR /ALONG
   SRN EXTENSION OF 40-50 KT LLJ/ WITH 0-1 KM SRH VALUES OF 200-350
   M2/S2.  THIS IN CONJUNCTION WITH 40-50 KT OF EFFECTIVE BULK SHEAR
   AND THE MODERATE INSTABILITY SHOULD SUPPORT INTENSE BOWING AND
   SUPERCELL STRUCTURES WITH THE POTENTIAL FOR TORNADOES /A FEW
   POSSIBLY STRONG/...CORRIDORS OF DAMAGING WINDS AND HAIL.
   
   ...MIDDLE/UPPER MS VALLEY INTO THE OH VALLEY...
   
   NRN EXTENSION OF NOCTURNAL QLCS MENTIONED ABOVE HAS PROGRESSED WELL
   E OF SURFACE COLD FRONT INTO WRN KY/SRN IL WITH AN ADDITIONAL BAND
   OF TSTMS INTENSIFYING FROM HOP NWD INTO WRN IND AS OF 1530Z.  MODEL
   GUIDANCE INDICATES THAT 45-55 KT LLJ WILL RAPIDLY DEVELOP NEWD INTO
   THE OH VALLEY AND SRN GREAT LAKES TODAY: 1) SUPPORTING BOUNDARY
   LAYER MOISTENING/DESTABILIZATION...AND 2) RESULTING IN INCREASINGLY
   STRONG VERTICAL SHEAR PROFILES.  AS SUCH...EXPECT ONGOING STORMS TO
   INTENSIFY WHILE PROGRESSING EWD ACROSS THE OH VALLEY WITH EMBEDDED
   SUPERCELLS AND BOWING/LEWP STRUCTURES CAPABLE OF A FEW
   TORNADOES...DAMAGING WINDS AND HAIL.
   
   ADDITIONAL TSTMS WILL BE POSSIBLE LATER TODAY FROM VICINITY OF
   OCCLUDING SURFACE LOW SWD ALONG TRAILING COLD FRONT FROM ERN IA/SRN
   WI SWD ACROSS ERN MO AND IL.  CONSIDERABLE MID/HIGH-LEVEL CLOUDINESS
   SHOULD TEND TO RESTRICT DAYTIME HEATING...THOUGH THE COLD MIDLEVEL
   TEMPERATURES ASSOCIATED WITH CLOSED UPPER LOW WILL SUPPORT WEAK TO
   POTENTIALLY MODERATE INSTABILITY AHEAD OF FRONT THIS AFTERNOON. 
   SHOULD SUFFICIENT DESTABILIZATION OCCUR...THE STRONGLY BACKED
   SURFACE WINDS IN ADVANCE OF SURFACE LOW SUGGEST THAT A CORRIDOR OF
   LOW-TOPPED SUPERCELLS CAPABLE OF LARGE HAIL AND PERHAPS A FEW
   TORNADOES.  FOR ADDITIONAL NEAR TERM GUIDANCE...PLEASE SEE MCD 772.
   
   ..MEAD/DIAL.. 05/02/2008
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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