MKC AC 240619   STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWBC.   VALID 241200Z - 251200Z THERE IS A HIGH RISK OF SVR TSTMS TODAY ACROSS SERN MO...SRN AND ERN IL...MUCH OF IN...SRN MI...WRN OH...AND NRN KY. THE HIGH RISK AREA IS TO THE RIGHT OF A LINE FROM 25 WNW CLE 25 NE CMH 55 SE LUK HOP 25 WNW DYR 25 N POF BLV 15 NW CMI 50 S CGX 10 SSW LAN 15 E MTC.   SURROUNDING THE HIGH RISK AREA...THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 ENE ROC 45 WSW ELM 20 NNE EKN 15 WNW BKW 30 WNW TYS 10 WNW HSV 25 ESE GWO 45 NNE MLU 15 ESE ELD 40 NW ELD 15 W HOT 25 S HRO 40 W UNO 25 NW STL 15 WNW SPI 20 SSE PIA 35 S RFD 30 W MKE 20 SSE MTW 35 NNW APN. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 NNE GLS 30 W LFK 30 N TYR 25 WNW PGO 15 NNW UMN 25 SW JEF 30 SSW UIN 20 NNE BRL 45 NW DBQ 20 W EAU 10 NW DLH 20 N ELO ...CONT... 50 WNW 3B1 35 WSW BHB.   -- SIGNIFICANT SEVERE WEATHER OUTBREAK EXPECTED ACROSS THE MID MS AND OH VALLEY INTO SRN GREAT LAKES REGION -- ...SYNOPSIS... MID-LEVEL TROUGH ACROSS THE CENTRAL PLAINS AT THE BEGINNING OF THE PERIOD WILL BECOME NEGATIVELY TILTED AS IT MOVES EWD ACROSS THE OH VALLEY -- WHILE A CLOSED LOW DEVELOPS AND MOVES INTO THE GREAT LAKES. VERY STRONG MID-LEVEL JET STREAK WILL STRENGTHEN TO 80 TO 100 KT DURING THE PERIOD AS IT ROUNDS THE BASE OF THE TROUGH AND MOVES INTO THE OH VALLEY REGION.   AT THE SURFACE...MAIN FEATURE DRIVING CONVECTIVE DEVELOPMENT WILL LIKELY BE A COLD FRONT EXTENDING SSWWD FROM A SURFACE LOW INITIALLY FORECAST OVER NERN MN. THIS LOW IS FORECAST TO MOVE SLOWLY ENEWD ACROSS LAKE SUPERIOR INTO ONTARIO WHILE RAPIDLY DEEPENING DURING THE SECOND HALF OF THE PERIOD TO NEAR 970 MB. AS THE LOW MOVES ENEWD...COLD FRONT IS FORECAST TO MOVE EWD TO IN / WRN KY / WRN TN / NRN MS BY SUNSET...AND THEN ACROSS THE APPALACHIANS BY THE END OF THE PERIOD. ANOTHER SURFACE FEATURE FORECAST TO BE OF SIGNIFICANCE RELATIVE TO THE CONVECTIVE EVOLUTION WILL LIKELY BE A W-E OUTFLOW BOUNDARY INITIALLY ACROSS KY ASSOCIATED WITH ONGOING CONVECTION. THIS BOUNDARY IS FORECAST TO LIFT NWD ACROSS THE OH RIVER VALLEY INTO IN AND OH DURING THE DAY -- AND SHOULD BE THE FOCUS OF PRE- FRONTAL SEVERE STORM DEVELOPMENT. ...MID MS AND OH VALLEY INTO THE SRN GREAT LAKES REGION... THUNDERSTORMS ARE FORECAST TO BE ONGOING AT THE BEGINNING OF THE PERIOD ACROSS PARTS OF SRN IL / SRN IN / OH / NRN KY. A W-E OUTFLOW BOUNDARY SEPARATING RAIN-COOLED AIR FROM THE WARM MOIST CONVECTIVELY-UNDISTURBED AIR ACROSS THE MID SOUTH REGION IS FORECAST ACROSS KY EARLY IN THE PERIOD. THUNDERSTORMS WILL LIKELY WEAKEN SOMEWHAT BUT CONTINUE THROUGH THE MORNING...WHILE NEW STORMS ARE FORECAST TO DEVELOP IN AREA OF STRONG THETA-E ADVECTION / CONVERGENCE NEAR OUTFLOW BOUNDARY. MEANWHILE...THUNDERSTORMS MAY BE ONGOING ALONG COLD FRONT IN WRN IL / NERN MO ALONG ADVANCING COLD FRONT...AND SHOULD DEVELOP SWD ALONG BOUNDARY ACROSS MO INTO AR BY MIDDAY. AS OUTFLOW BOUNDARY INITIALLY OVER KY LIFTS NWD DURING THE DAY ON STRENGTHENING LOW-LEVEL SLY FLOW...COLD FRONT WILL CONTINUE EWD INTO THE OH VALLEY REGION. AIRMASS WILL BE MOIST ACROSS THE REGION...WITH DEWPOINTS FORECAST FROM THE LOW 60S IN THE SRN GREAT LAKES TO THE UPPER 60S INVOF THE OH VALLEY. ALTHOUGH HEATING WILL LIKELY BE LIMITED ACROSS MUCH OF THE AREA DUE TO CLOUD COVER...FAIRLY STEEP MID-LEVEL LAPSE RATES BEING ADVECTED INTO THE REGION WILL COMBINE WITH THE MOIST LOW-LEVEL ATMOSPHERE TO YIELD SURFACE-BASED CAPE GENERALLY 1000 TO 2000 J/KG INVOF THE OH VALLEY...AND 500 TO 1000 J/KG NWD INTO THE SRN GREAT LAKES REGION. AMOUNT OF INSTABILITY ALONG WITH LOW-LEVEL FORCING ALONG FRONT / OUTFLOW BOUNDARY AND STRONG DIVERGENCE ALOFT ASSOCIATED WITH ENTRANCE REGION OF APPROACHING UPPER JET WILL LIKELY RESULT IN AN AREA OF WIDESPREAD SEVERE THUNDERSTORMS IN AND NEAR THE HIGH RISK AREA DURING THE AFTERNOON / EVENING.   DEEP-LAYER SHEAR WILL BE QUITE STRONG ACROSS THE REGION AS SWLY MID-LEVEL FLOW INCREASES TO 60 TO 70 KTS AS JET STREAK APPROACHES ABOVE 50 TO 60 KT SSWLY LOW-LEVEL JET OVER THE REGION. AS A RESULT...EXPECT DEVELOPING STORMS TO RAPIDLY BECOME SEVERE...WITH SUPERCELLS LIKELY ALONG WITH BOWS EMBEDDED WITHIN LINEARLY- ORGANIZED CLUSTERS. ATTM...GREATEST ISOLATED STORM / SUPERCELL THREAT APPEARS TO EXIST ALONG AND NEAR NWD-MOVING OUTFLOW BOUNDARY AHEAD OF FRONT FROM THE OH VALLEY REGION NWD INTO SRN LOWER MI. STORMS WILL LIKELY BE MORE LINEARLY-ORGANIZED -- BUT WITH EMBEDDED BOWS AND SUPERCELLS -- INVOF APPROACHING COLD FRONT. GREATEST SEVERE THREAT ATTM APPEARS TO BE DAMAGING WINDS -- WITH SIGNIFICANT WIND DAMAGE POSSIBLE. TORNADO THREAT ALSO APPEARS TO BE FAIRLY HIGH...PARTICULARLY WITH ISOLATED STORMS NEAR OUTFLOW BOUNDARY AHEAD OF FRONT...WHERE LOW-LEVEL FLOW WILL LIKELY BE MORE BACKED. A FEW SIGNIFICANT TORNADOES WILL BE POSSIBLE...AND LARGE HAIL WILL ALSO BE LIKELY ACROSS THE AREA. AFTER SUNSET...AS STORMS MOVE EWD TOWARD PA / NY...LESS UNSTABLE AIRMASS IN THIS REGION WILL LIKELY STABILIZE FURTHER WITH LOSS OF DAYTIME HEATING. AS A RESULT... STORMS WILL LIKELY BE LIMITED TO REGION OF STRONGEST LOW-LEVEL FORCING ALONG COLD FRONT...WITH DAMAGING WINDS BECOMING THE MAIN THREAT OVERNIGHT.   ..GOSS.. 10/24/01