SPC AC 301259
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0759 AM CDT SUN MAY 30 2004
   
   VALID 301300Z - 311200Z
   
   THERE IS A HIGH RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 SE
   PAH 40 S MKL 20 WNW ELD 25 NW TXK 35 SSE PGO 10 S FSM 40 NNE SGF 40
   NE UIN 20 NNW MMO 35 E MMO 30 N DNV 25 SSW HUF 30 SE PAH.
   
   THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 NE
   MSL GLH 20 SSW ELD 40 NW TYR 35 WSW PRX 30 SSE MKO 35 WNW SGF 35 W
   UIN 25 W MLI 30 N DBQ 15 NE LNR 40 ESE MKE 25 NNW FWA 20 NE SDF 20
   ESE BWG 25 NE MSL.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 NNW
   MGM 30 SW LUL 25 SSE ESF 45 E CLL 40 WSW CLL 25 SW AUS 40 NNE HDO 30
   SSE JCT 25 NNW JCT 15 WNW BWD 10 SW DAL 25 SW MLC 10 E OJC 35 N DSM
   15 S MKT 30 SW STC 35 ENE BRD 25 SSW IWD 35 ESE MTW 40 SE DTW 20 SSE
   CAK 30 ENE PKB 25 SSE 5I3 25 SE RMG 20 WNW LGC 25 NNW MGM.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 NNW JHW 15 ESE NEL
   ...CONT... SSI 25 ESE GNV 10 N SRQ ...CONT... 45 NW DRT 40 SW SJT 40
   NE SJT 20 W MWL 20 SW ADM 35 WSW TUL 35 NE PNC 40 NNE ICT 30 SE HSI
   15 NNW MHN 15 NW PHP 45 S BIS 50 NNW MOT.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 NNW CTB 25 SSE HLN
   27U 80 S S80 BKE 30 ENE BLI.
   
   ...THERE IS A HIGH RISK OF SVR TSTMS OVER MUCH OF AR/SERN MO/CNTRL
   AND SRN IL/WRN KY AND WRN TN/NWRN MS...
   
   ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK OVER
   SRN WI/NRN IL/IND/KY/TN/NWRN MS/NERN TX/SERN OK AND CNTRL MO...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM NERN TX TO THE UPPER MS
   VALLEY AND LOWER MI...
   
   ...SIGNIFICANT SEVERE WEATHER OUTBREAK POSSIBLE TODAY OVER PARTS OF
   WRN/CNTRL ARKANSAS AND THE MIDDLE MISSISSIPPI VALLEY INTO THE
   MIDWEST AND LOWER OH VALLEY...
   
   ...LONG-TRACK TORNADOES AND CONSIDERABLE WIND DAMAGE COULD OCCUR
   OVER THESE AREAS THROUGH THE EVENING...
   
   ...CITIES IN THE HIGH RISK AREA INCLUDE SPRINGFIELD, IL...ST. LOUIS,
   MO...LITTLE ROCK, AR...AND MEMPHIS, TN...
   
   ...SYNOPSIS...
   UNSEASONABLY DEEP TROPOSPHERIC TROUGH AND ASSOCIATED COLD FRONT WERE
   LOCATED OVER THE CNTRL U.S. THIS MORNING WITH ABUNDANT SHORT WAVE
   ENERGY EMERGING FROM THE BASE OF THE TROUGH OVER THE SRN HIGH
   PLAINS. DOWNWIND FROM THE TROUGH AXIS...A HIGH AMPLITUDE MID LEVEL
   RIDGE EXTENDED FROM THE OH VALLEY NNWWD ACROSS THE GREAT LAKES TO
   SRN CANADA. AS SIGNIFICANT HEIGHT FALLS DEVELOP EAST WITH THE TROUGH
   THROUGH TONIGHT...A BROAD BAND OF 60-80KT STRONGLY DIFFLUENT MID
   LEVEL FLOW WILL SPREAD ATOP A VERY MOIST AND INCREASINGLY UNSTABLE
   WARM SECTOR FROM AR/MO TO THE MIDWEST/OH VALLEY. CONSIDERABLE LARGE
   SCALE UPWARD VERTICAL MOTION WILL ACT ON THE WARM SECTOR AIRMASS AND
   RESULT IN WIDESPREAD STRONG TO SEVERE TSTMS. TSTMS SHOULD BECOME
   INCREASINGLY FOCUSED WITH TIME ALONG/AHEAD OF THE COLD FRONT AS IT
   SURGES EAST FROM THE MO RIVER VALLEY THIS MORNING TO THE OH/TN AND
   LOWER MS VALLEYS BY MONDAY MORNING. ADDITIONAL STRONG AND POSSIBLY
   SEVERE STORMS WILL ACCOMPANY THE LOW AND OCCLUDED FRONT LIFTING NEWD
   OVER THE UPPER MS VALLEY TODAY...AS WELL AS THE NWD MOVING WARM
   FRONT...EXTENDING FROM THE OH VALLEY ACROSS THE LOWER GREAT LAKES.
   
   ...AR/MO/IL TO IND...
   VERY MOIST BOUNDARY LAYER WITH DEWPOINTS IN THE 70S...COUPLED WITH
   SURFACE TEMPERATURES CLIMBING INTO THE UPPER 80S AND LOWER 90S...
   WILL CONTRIBUTE TO THE DEVELOPMENT OF EXTREME INSTABILITY /MLCAPE
   3000-4000 J/KG/ FROM TXK TO WRN IL BY THIS AFTERNOON. COMBINATION OF
   LARGE SCALE ASCENT/DIFFLUENCE AHEAD OF THE TROUGH...AND FRONTAL
   CIRCULATION SPREADING EAST FROM THE PLAINS WILL BE SUFFICIENT TO
   OVERCOME WEAK CONVECTIVE INHIBITION AND PROMOTE EXPLOSIVE TSTM
   DEVELOPMENT ALONG AND AHEAD OF THE FRONT BY AFTERNOON. STRONG DEEP
   LAYER SHEAR...WITH VECTORS ORIENTED PERPENDICULAR TO THE FRONTAL
   FORCING...WILL INITIALLY SUPPORT DISCRETE TORNADIC SUPERCELLS.
   ADDITIONALLY...GIVEN DEGREE OF LARGE SCALE ASCENT SPREADING AHEAD OF
   THE COLD FRONT...WEAK CAP...AND STRENGTH OF DEEP SHEAR ACROSS THE
   WARM SECTOR...FAMILIES OF TORNADIC SUPERCELLS MAY DEVELOP WELL AHEAD
   OF THE ACTUAL SURFACE FRONT. THIS ACTIVITY SHOULD TRACK E/NEWD
   ACROSS NRN AR/ERN MO AND WRN IL THROUGH THE LATE AFTERNOON  WITH
   LONG-TRACK STRONG TORNADOES...LARGE HAIL...AND DAMAGING OUTFLOW
   WINDS ALL POSSIBLE.
   
   BY EVENING...LOW AND MID LEVEL FLOW IS FCST TO BECOME INCREASINGLY
   ALIGNED WITH FORCING ALONG THE FRONTAL BAND...ESPECIALLY FROM MO
   BOOTHEEL TO IL. THIS SUGGESTS AN EVENTUAL EVOLUTION INTO A BOWING
   SQUALL LINE WITH THE POTENTIAL FOR WIDESPREAD DAMAGING WINDS
   SPREADING EAST ACROSS IL AND INTO WRN IND DURING THE NIGHT. THIS
   APPEARS TO BE SUPPORTED BY THE PATTERN OF THE MASS FIELDS IN THE
   MESOSCALE MODELS...AND FCST OF STRONG MID LEVEL DRY INTRUSION AND
   50-60KT MID LEVEL FLOW DIRECTED INTO THE BACK OF THE CONVECTIVE
   LINE.
   
   ...EXTREME SERN OK/NERN TX ACROSS THE LOWER MS VALLEY/TN VALLEY...
   WARM SECTOR AIRMASS FROM NERN TX TO MIDDLE TN WILL ALSO BE VERY
   MOIST AND UNSTABLE. WIDELY SCATTERED SUPERCELLS WITH TORNADIC
   POTENTIAL COULD DEVELOP THIS AFTERNOON WELL AHEAD OF THE FRONTAL
   ZONE FROM THE LOWER MS VALLEY TO MIDDLE TN GIVEN STRONG SURFACE
   HEATING AND RELATIVELY WEAK CAP. MORE CONCENTRATED ACTIVITY IS
   LIKELY TO DEVELOP AND FOCUS ON THE TRAILING PORTION OF THE FRONT AS
   IT DEVELOPS SEWD INTO INSTABILITY AXIS FROM SERN OK INTO WRN AR AND
   NERN TX LATER TODAY. INSTABILITY AND SHEAR PARAMETERS WILL INITIALLY
   FAVOR SUPERCELL TORNADOES BUT ACTIVITY MAY THEN BACKBUILD AND BECOME
   LINEAR ALONG THE FRONTAL BOUNDARY FROM LATE EVENING ON. GIVEN
   MAGNITUDE OF DOWNSTREAM INSTABILITY ACROSS THE LOWER MS VALLEY AND
   TN VALLEY...AND STRONG WLY COMPONENT OF TROPOSPHERIC FLOW...A FAST
   MOVING FORWARD PROPAGATING MCS IS LIKELY TO EVOLVE AND SPREAD
   EWD/SEWD INTO EARLY MONDAY MORNING. THERE IS UNCERTAINTY AS TO HOW
   FAR EAST A WIND DAMAGE THREAT WILL EXTEND WITH DIFFERENCES IN
   ETA/GFS MODEL GUIDANCE. GREATEST WIND DAMAGE POTENTIAL WILL LIKELY
   BE FROM SRN AR TO THE TN VALLEY DURING THE LATE EVENING. HOWEVER...A
   SQUALL LINE WITH DAMAGING WINDS COULD POTENTIALLY SPREAD ACROSS MOST
   OF THE SOUTH AND INTO THE SRN APPALACHIANS BY DAYBREAK.
   
   ...UPPER MS VALLEY TO LOWER GREAT LAKES...
   AS PRIMARY SURFACE LOW OCCLUDES OVER ERN SD THIS MORNING...A
   SECONDARY TRIPLE POINT LOW APPEARS TO BE TAKING SHAPE ACROSS NRN IL
   WITH A WARM FRONT EXTENDING SEWD ACROSS SRN IND. AIRMASS TO THE 
   EAST OF THE OCCLUDED FRONT...AND NORTH OF THE WARM FRONT IS EXPECTED
   TO REMAIN ONLY MARGINALLY UNSTABLE TODAY GIVEN LOW LEVEL
   TRAJECTORIES FROM CP AIRMASS ACROSS THE ERN LAKES/NORTHEAST.
   NONETHELESS...STRONG ASCENT ACROSS WARM FRONT...BROADLY DIFFLUENT 
   MID LEVEL FLOW...AND STEEP MID LEVEL LAPSE RATES SHOULD SUPPORT A
   FEW SEVERE STORMS WITH HAIL...AND A COUPLE OF SUPERCELLS NEAR THE
   WARM FRONT FROM SRN WI ACROSS LOWER MI AND INTO WRN OH.
   
   ..CARBIN/TAYLOR.. 05/30/2004
   
   ...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 1630Z