SPC AC 171947
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0247 PM CDT SAT APR 17 2004
   
   VALID 172000Z - 181200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 45 NW
   ERI 30 NW HLG 25 WSW CMH 15 ENE MMO 20 ESE DSM 10 NNE OMA 40 WNW YKN
   10 SW ATY 15 NW STC 30 E RHI APN.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 SE
   EHA 25 E LBL 55 W GAG 25 ENE AMA 10 N PVW 50 WSW LBB 25 SSE CVS 10
   SW DHT 25 SSW EHA 25 SE EHA.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SE FHU 80 NW TCS
   15 E GUP 75 NW GUP 30 NE GCN 25 N EED 20 NNW IPL 10 SE SAN 15 WNW
   PRB 35 E UKI 10 SSE MFR 55 SE EUG 15 SSE DLS 30 W LWS 45 W GTF 65 NW
   GGW ...CONT... 55 NNE ISN 30 WNW P24 55 NE BIS 25 SSE GFK 50 WNW HIB
   20 N ELO ...CONT... 50 NNE BML 15 NW RUT 10 ENE BFD 25 SE MGW 25 NW
   HTS 40 SE IND 25 N HUF 45 ENE BMI 35 NE IRK 25 SSW LWD 10 WSW FNB 35
   WSW HUT 50 SSW CDS 15 NE BGS 25 E P07.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO VLY EWD INTO
   THE GREAT LAKES/MIDWEST...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FOR A SMALL PORTION OF THE SRN
   HIGH PLAINS...
   
   ...UPPER MS VLY REGION...
   BOUNDARY LAYER IS RECOVERING QUICKLY ACROSS THE MID MO VLY THIS
   AFTERNOON AND REMNANT OUTFLOW/FRONT IS BEGINNING TO REDEVELOP NWD. 
   THOUGH SUBSTANTIAL CINH EXISTS...PERSISTENT HEATING AND CONVERGENCE
   SHOULD BE ENOUGH TO BREACH THE CAP LATE THIS AFTERNOON RESULTING IN
   INITIATION IN AN ENVIRONMENT CHARACTERIZED BY 2000-2500 J/KG MLCAPE.
    RUC MODEL HAS BEEN CONSISTENT AND IS IN AGREEMENT WITH LAST NIGHTS
   00 UTC WRF SOLUTION...INITIATING TSTMS OVER WCNTRL/NWRN IA NEAR THE
   MO RVR BY 00 UTC.
   
   MAGNITUDE OF INSTABILITY AND VERTICAL SHEAR SUGGEST STORMS COULD
   ORGANIZE QUICKLY INTO SUPERCELLS WITH VERY LARGE HAIL. FORECAST
   HODOGRAPHS EXHIBIT RATHER LARGE LOOPING HODOGRAPHS...SO DESPITE 
   RATHER HIGH LCLS...THE TORNADO THREAT IS NON-ZERO.
   
   TSTMS ARE APT TO DEVELOP ENEWD INTO THE UPPER MS VLY LATER
   TONIGHT...LIKELY BECOMING MORE ELEVATED WITH TIME.  WHILE A DAMAGING
   WIND THREAT WILL EXIST ACROSS NRN IA FOR A TIME THIS
   EVENING...TRANSITION INTO MAINLY A LARGE HAIL THREAT SHOULD OCCUR
   OVERNIGHT ACROSS PARTS OF WI AND UPPER MI.
   
   ...MIDWEST/UPPER OH VLY...
   FRONT/OUTFLOW CONTINUES TO SETTLE SEWD FROM LK ERIE ACROSS EXTREME
   NW OH...NRN IND/IL AT MID AFTERNOON.  STRONGEST LOW LEVEL
   CONVERGENCE HAS BEEN PERSISTENT FROM THE KFWA AREA EWD.  BOUNDARY
   LAYER HAS BECOME UNSTABLE WITH INFLUX OF NEAR 60F DEW POINTS BENEATH
    STEEP MIDLEVEL LAPSE RATES.  AS HEATING CONTINUES...THE CU FIELD
   VCNTY FRONT MAY EVENTUALLY SPROUT INTO CBS AFTER 21 UTC.  FARTHER
   WEST...SURFACE WIND REGIME SEEMS TO BE INCREASINGLY DIFFLUENT GIVEN
   THAT FLOW ALONG THE MS RVR IS RESPONDING TO PRESSURE FALLS UPSTREAM
   OVER IA/NEB.  THUS...REASONABLE CONFIDENCE EXISTS THAT THERE WILL BE
   A SEVERE THREAT MINIMUM OVER NRN IL...WITH HIGHER PROBABILITIES
   EXISTING IN IND/OH AND UPSTREAM OVER IA.
   
   REGION RESIDES ON SRN PERIPHERY OF STRONGER WLYS ALOFT...BUT
   VERTICAL SHEAR DROPS OFF AOB 30 KTS FARTHER SOUTH.  THE MAIN STORM
   MODE SHOULD MAINLY BE MULTICELLS GIVEN THE WEAKER SHEAR...BUT A
   SUPERCELL OR TWO CANNOT BE RULED OUT...PARTICULARLY A COUPLE HOURS
   AFTER ONSET.  DEW POINT DEPRESSIONS ARE STILL RATHER LARGE...AND
   GIVEN UNIDIRECTIONAL VERTICAL FLOW...TSTMS WILL TEND TO GENERATE
   SUBSTANTIAL OUTFLOWS AND MAY EXHIBIT BOWS/LEWPS AS THE EVOLUTION
   MATURES OVER NRN/CNTRL OH DURING THE EVENING. WHILE LARGE HAIL WILL
   BE POSSIBLE...A RISK OF DAMAGING WIND WILL ALSO BE LIKELY BEFORE
   ACTIVITY DIMINISHES LATER TONIGHT OVER THE UPPER OH VLY.
   
   ...SRN HIGH PLAINS...
   CONDITIONAL PROBABILITIES FOR AN ISOLD SEVERE TSTM EXIST FROM
   CNTRL/ERN OK PNHDL SWD TO NM/TX BORDER AREA.  ISOLD TSTMS ARE
   POSSIBLE ALONG LEE-TROUGH/DRYLINE LATER THIS AFTERNOON AS A WEAK
   IMPULSE RIDES NEWD INTO THE SRN HIGH PLAINS.  CONCERN IS THAT
   CONTINUED HEATING ALONG THE DRYLINE WILL BE ABATED BY HIGH CLOUD
   CANOPY AND LOW LEVEL HEATING WILL NOT BE ABLE TO COMPENSATE FOR
   WARMING TEMPERATURES ALOFT.  IF A TSTM CAN MANAGE TO FORM...LARGE
   HAIL COULD OCCUR.
   
   ..RACY.. 04/17/2004
   
   ...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 1 OUTLOOK IS SCHEDULED FOR 0100Z