SPC AC 181630
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1130 AM CDT SUN APR 18 2004
   
   VALID 181630Z - 191200Z
   
   THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 50 ESE
   ELO CMX RHI EAU 10 E FRM OTG 30 E BKX AXN HIB 50 ESE ELO.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 NNE
   PBG GFL 30 W ALB ITH 10 WSW BUF.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM APN
   MSN DSM 10 NNE FNB BIE 10 NE GRI LBF MHN VTN MHE ATY 45 ESE FAR 10
   ENE BJI 35 ESE INL.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 70 SW GDP 40 NW HOB
   45 ENE DHT 30 WSW HLC 20 SW MCK 40 WSW IML 15 NW AKO 25 SE FCL 50 S
   4FC 35 S GUC 15 ESE CEZ 25 SE U17 60 WNW 4HV DPG 30 SW TWF 50 SE BNO
   35 NNW BNO 20 NNE YKM 65 ENE BLI ...CONT... 40 NE HVR 45 NNE LWT 50
   SE LWT 30 E BIL 30 NW 4BQ 35 SE SDY 25 WNW MOT 65 NNW DVL ...CONT...
   50 NNE BML 25 NNW EEN 20 SSW POU 10 WNW TTN 35 NW ILG 20 S PSB 10 NE
   CAK 25 E MIE 15 WNW HUF 20 W SLO 45 NW CGI 40 N POF 20 W ARG 30 W
   LIT 35 S PGO 15 S DUA 45 NW AUS 70 W COT.
   
   ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
   PARTS OF MN/WI/UPPER MI...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE MIDWEST
   STATES...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF NY...
   
   ...MN/WI/UPPER MI THIS AFTERNOON/EVENING...
   WATER VAPOR IMAGERY SHOWS POTENT UPPER LEVEL SHORTWAVE TROUGH OVER
   CO/NM. THIS FEATURE IS FORECAST TO TRACK NORTHEASTWARD INTO THE
   CENTRAL PLAINS AND MIDWEST STATES THIS AFTERNOON AND
   EVENING...SETTING THE STAGE FOR AN ACTIVE SEVERE WEATHER EVENT
   ACROSS PARTS OF MN/WI/UPPER MI.  MORNING MODEL GUIDANCE IS IN
   AGREEMENT THAT MAIN SURFACE LOW WILL TRACK FROM SOUTHERN MN
   NORTHEASTWARD ALONG WARM FRONT ACROSS NORTHWEST WI AND THE WESTERN
   U.P. OF MI THIS EVENING.  MORNING VISIBLE SATELLITE IMAGERY SUGGESTS
   LOW CLOUDS WILL LIKELY DIMINISH ALONG THIS AXIS...ALLOWING AIRMASS
   TO WARM/DESTABILIZE WITH AFTERNOON MLCAPE VALUES OF AROUND 2000
   J/KG.  VERY STRONG WIND FIELDS WILL ALSO DEVELOP ALONG/EAST OF THIS
   AXIS WITH 850MB WINDS OF 50-70 KNOTS AND CONSIDERABLE LOW LEVEL
   VEERING WIND PROFILES. FORECAST SOUNDINGS SHOW 3KM HELICITY VALUES
   NEAR 500 M2/S2 AND VERY STRONG DEEP LAYER SHEAR.
   
   MAIN FORECAST CONCERN OVER THIS REGION IS THE STRENGTH OF THE
   CAPPING INVERSION.  RELATIVELY LARGE INHIBITION VALUES WILL LIKELY
   SUPPRESS DEEP CONVECTION IN THE WARM SECTOR...WITH ACTIVITY
   REMAINING FOCUSED NEAR THE SURFACE LOW AND WARM/COLD FRONTS. 
   SUPERCELLS WITH VERY LARGE HAIL AND TORNADOES APPEAR LIKELY IN THIS
   AREA...WITH A TRANSITION TO A FAST MOVING MCS PRODUCING DAMAGING
   WINDS AND HAIL BY LATE EVENING.
   
   ...NORTHERN NY EARLY AFTERNOON...
   SHORT LINE OF SEVERE STORMS NEAR BUF WILL MOVE EASTWARD ACROSS
   NORTHERN NY THROUGH EARLY AFTERNOON.  THESE STORMS ARE ALONG/NORTH
   OF SURFACE BOUNDARY...AND IN REGION OF MARGINAL ELEVATED CAPE
   /500-1000 J/KG/.  SOME QUESTION EXISTS REGARDING THE EASTWARD EXTENT
   OF THE SEVERE THREAT AS LOW LEVEL JET INTENSIFIES TO THE WEST AND
   LOW LEVEL FORCING WEAKENS.  HOWEVER...GIVEN ORGANIZED MESOSCALE
   NATURE OF CONVECTIVE SYSTEM...POTENTIAL WILL REMAIN FOR LARGE HAIL
   AND DAMAGING WINDS IN STRONGER CELLS.  REF NEW WW 0081.
   
   ...NORTHERN NEB/NORTHWEST IA THIS AFTERNOON/EVENING...
   LATEST SURFACE MAP SHOWS SURFACE COLD FRONT SURGING SOUTHWARD ACROSS
    SD.  RUC/ETA GUIDANCE SHOW THE DEVELOPMENT OF STEEP LOW LEVEL LAPSE
   RATES...STRONG SURFACE WINDS...AND SUFFICIENT INSTABILITY FOR
   SCATTERED THUNDERSTORMS.  ACTIVITY WILL LIKELY DEVELOP ALONG/AHEAD
   OF THE FRONT OVER NORTHERN NEB AND SPREAD EASTWARD INTO NORTHWEST
   IA. DAMAGING WINDS AND LARGE HAIL APPEAR POSSIBLE IN STRONGER CELLS.
   
   
   ...KS/MO/OK/TX...
   SURFACE DRYLINE IS FORECAST TO BECOME FOCUSED FROM SOUTHEAST NEB
   ACROSS CENTRAL KS INTO THE EASTERN TX PANHANDLE THIS AFTERNOON.  A
   VERY STRONG CAPPING INVERSION WILL LIKELY REMAIN IN PLACE OVER THIS
   AREA THROUGH THE DAY...WITH MINIMAL FORCING FOR CONVECTIVE
   DEVELOPMENT.  NEVERTHELESS...VERTICAL SHEAR PROFILES ARE QUITE
   FAVORABLE FOR SUPERCELLS IF STORMS CAN DEVELOP.  SOME POTENTIAL ALSO
   EXISTS FOR A FEW VERY HIGH BASED STORMS ROOTED ABOVE THE CAPPING
   VERSION PRODUCING GUSTY/DAMAGING WINDS.  12Z RUC AND 09Z ETAKF
   SOLUTIONS DO DEVELOP ISOLATED CONVECTION ALONG DRYLINE...AND
   ISOLATED ELEVATED SHOWERS/THUNDERSTORMS HAVE DEVELOPED OVER WESTERN
   OK/EASTERN TX PANHANDLE THIS MORNING. THUS WILL MAINTAIN LOW
   PROBABILITIES OF HAIL/WIND ALONG THIS AXIS.
   
   ..HART/TAYLOR.. 04/18/2004
   
   ...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 2000Z