SPC AC 131231
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0731 AM CDT SUN JUN 13 2004
   
   VALID 131300Z - 141200Z
   
   THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 WNW
   SLN FNB 30 SSE BRL 35 WSW SPI 40 ENE COU COU SZL 25 N JLN 20 SW JLN
   BVO PNC P28 25 WNW SLN.
   
   THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 10 E
   DTW 20 SSW JXN BEH 15 NNW MKG HTL 10 NE OSC.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 35 NE
   BUF 10 ENE BFD 10 NE ZZV BMG UNO ARG JBR MEM GLH ELD PRX OKC GAG RSL
   LNK 40 WSW LNR CWA 35 W IMT 15 NNE CMX.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 90 SSE MRF 30 NE HLC
   BUB 30 NNE ANW 40 NNE CDR 50 SSE 81V 20 WNW WRL 20 ENE BTM 40 S FCA
   45 NNE 4OM ...CONT... 45 NNE BML 30 ENE EFK 15 WNW ILG 15 WSW RIC 20
   S OAJ.
   
   ...THERE IS A MDT RISK OF SVR TSTMS TODAY ACROSS LOWER MICHIGAN....
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF THE CENTRAL
   PLAINS/LOWER MISSOURI VALLEY....
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SURROUNDING AREAS OF THE
   GREAT LAKES/OHIO VALLEY/MIDDLE MISSISSIPPI VALLEY/OZARKS AND CENTRAL
   PLAINS....
   
   LONG BELT OF STRONG ZONAL MID/UPPER FLOW IS READILY EVIDENT IN
   LATEST WATER VAPOR IMAGERY...EXTENDING ACROSS THE NORTHEAST PACIFIC
   INTO THE PACIFIC NORTHWEST COAST STATES.  JET CONTINUES EAST
   SOUTHEASTWARD ACROSS THE NORTH CENTRAL ROCKIES...AROUND BROAD UPPER
   RIDGE INTO REAR OF SHARP UPPER TROUGH PROGRESSING ACROSS THE PLAINS
   STATES.
   
   MODELS SUGGEST EXIT REGION OF UPPER JET WILL GRADUALLY NOSE ACROSS
   THE NORTH CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY DURING
   THIS FORECAST PERIOD.  AS THIS OCCURS...NORTHERN PORTION OF PLAINS
   TROUGH IS PROGGED TO ACCELERATE EAST NORTHEASTWARD ACROSS THE GREAT
   LAKES REGION INTO SOUTHEAST ONTARIO/QUEBEC.  SOUTHERN PORTION WILL
   BECOME MORE OR LESS CUT-OFF OVER THE WESTERN GULF STATES... EMBEDDED
   WITHIN WEAK SUBTROPICAL WESTERLIES.  DEEP LAYER MOIST SOUTHERLY FLOW
   IS FORECAST TO DEVELOP ACROSS THE CENTRAL GULF OF MEXICO...WITH
   POSSIBLE EMBEDDED TROPICAL CIRCULATION APPROACHING CENTRAL GULF
   COASTAL AREAS LATE TONIGHT.
   
   ...GREAT LAKES REGION...
   AHEAD OF NORTHERN BRANCH SHORT WAVE TROUGH...WARM FRONTAL ZONE IS
   ALREADY BEGINNING TO DEVELOP/LIFT THROUGH SOUTHERN LOWER MICHIGAN...
   WITH SURFACE DEW POINTS CLIMBING INTO THE MID 60S.  WARM FRONT IS
   EXPECTED TO PROGRESS THROUGH MUCH OF THE REMAINDER OF LOWER MICHIGAN
   BY EARLY AFTERNOON...AHEAD OF SURFACE WAVE AND ASSOCIATED MID-LEVEL
   CIRCULATION LIFTING OUT OF THE UPPER MISSISSIPPI VALLEY...LIKELY
   INTO WESTERN LOWER MICHIGAN BY 18Z.
   
   SURFACE HEATING IS EXPECTED TO BECOME SUFFICIENT FOR MODERATE TO
   STRONG DESTABILIZATION BY THIS AFTERNOON...WHEN MODEL FORECAST
   SOUNDINGS INDICATE MEAN MIXED LAYER CAPE WILL RANGE FROM 2000 TO
   3000 J/KG.  BELT OF 30 TO 50 KT WEST SOUTHWEST MID-LEVEL FLOW IN
   BASE OF BROAD NEGATIVELY TILTED SHORT WAVE TROUGH IS PROGGED TO
   OVERSPREAD WARM SECTOR DURING THE PEAK HEATING HOURS.  THIS WILL
   CONTRIBUTE TO STRONG VERTICAL SHEAR PROFILES SUPPORTIVE OF
   SUPERCELLS AS CONVECTION INITIATES...WITH POTENTIAL FOR VERY LARGE
   HAIL/DAMAGING WIND GUSTS.  A FEW TORNADOES ALSO APPEAR QUITE
   LIKELY...AS SOUTH/SOUTHEASTERLY SURFACE WINDS TO THE SOUTHEAST OF
   SURFACE WAVE ENHANCE LOW-LEVEL HODOGRAPHS.
   
   THOUGH WIND FIELDS ARE MODERATE IN STRENGTH...GIVEN MAGNITUDE OF
   INSTABILITY...POTENTIAL EXISTS FOR AN ISOLATED STRONG TORNADO OR
   TWO...PARTICULARLY NORTH NORTHEAST OF GRAND RAPIDS INTO THE SAGINAW
   AREA DURING THE 13/21Z-14/00Z TIME FRAME.
   
   ...CENTRAL PLAINS/MIDDLE MISSISSIPPI VALLEY...
   IN WAKE OF PRIMARY SHORT WAVE TROUGH...LOW-LEVEL CONFLUENT ZONE
   ACROSS NORTHEAST KANSAS THROUGH NORTHERN MISSOURI APPEARS LIKELY TO
   BECOME FOCUS FOR MOST SIGNIFICANT CONVECTIVE DEVELOPMENT THIS
   AFTERNOON AND EVENING. CONSIDERABLE SURFACE HEATING IS EXPECTED  BY
   THE AFTERNOON HOURS ACROSS THIS AREA...AND SURFACE DEW POINTS SHOULD
   CLIMB BACK THROUGH THE 60S AHEAD OF WEAK SURFACE FRONT.  THOUGH NOT
   AS PRONOUNCED AS PRIOR RUNS...LATEST MODEL FORECAST SOUNDINGS
   SUGGEST ENVIRONMENT WILL BECOME STRONGLY UNSTABLE BENEATH MID-LEVEL
   THERMAL TROUGH...WITH 100 MB MEAN MIXED LAYER CAPE EXCEEDING 3000
   J/KG.
   
   DESPITE STABILIZING INFLUENCE OF OVERNIGHT MCS...THIS STILL APPEARS
   POSSIBLE BY 14/00Z...WHEN EXIT REGION OF 90-110 KT HIGH-LEVEL JET IS
   PROGGED TO SHIFT ACROSS EASTERN KANSAS/WESTERN
   MISSOURI...CONTRIBUTING TO FORCING FOR CONVECTIVE DEVELOPMENT ALONG
   BOUNDARY.  ADDITIONAL FOCUS FOR CONVECTIVE INITIATION MAY BE
   PROVIDED BY OUTFLOW BOUNDARY RETREATING NORTHEASTWARD ACROSS EASTERN
   KANSAS ON NOSE OF 20 TO 30 KT SOUTHERLY LOW-LEVEL JET.
   
   GIVEN MAGNITUDE OF CAPE...SHEAR BENEATH WEST NORTHWESTERLY UPPER
   FLOW REGIME WILL BE MORE THAN SUFFICIENT FOR SUPERCELLS.  A FEW OF
   THESE MAY BECOME QUITE INTENSE/LONG-LIVED.  LARGE HAIL...INCLUDING
   POTENTIAL FOR VERY LARGE HAIL...IS LIKELY PRIMARY THREAT...BUT
   ISOLATED TORNADOES ARE ALSO POSSIBLE.  AS ACTIVITY SPREADS SLOWLY
   EAST/SOUTHEASTWARD...SEVERE THREAT MAY PERSIST THROUGH MUCH OF THE
   EVENING...BEFORE SLOWLY DIMINISHING AS ENVIRONMENT STABILIZES
   OVERNIGHT.
   
   ...EASTERN OKLAHOMA INTO ARKANSAS...
   OUTFLOW BOUNDARY ASSOCIATED WITH OVERNIGHT CONVECTION IS EXPECTED TO
   STALL OUT ROUGHLY ALONG/NORTH OF INTERSTATE 40.  DEW POINTS
   ALONG/SOUTH OF BOUNDARY WILL REMAIN IN THE LOWER 70S... CONTRIBUTING
   TO POTENTIALLY STRONG INSTABILITY WITH SURFACE HEATING.  GIVEN
   RATHER WEAK CAPPING...MID-LEVEL CIRCULATION MIGRATING EAST
   NORTHEASTWARD OUT OF SOUTH CENTRAL OKLAHOMA SHOULD AID CONVECTIVE
   DEVELOPMENT ALONG BOUNDARY.  DESPITE WEAK FLOW/SHEAR...THERMODYNAMIC
   ENVIRONMENT AND VERTICAL VORTICITY ASSOCIATED WITH CIRCULATION
   APPEAR SUPPORTIVE OF ISOLATED BRIEF TORNADOES AND DOWNBURSTS THROUGH
   EARLY THIS EVENING.
   
   ..KERR/CROSBIE.. 06/13/2004
   
   ...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