SPC AC 220559 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1259 AM CDT WED JUN 22 2016 VALID 221200Z - 231200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF ERN IA...SRN WI...NRN IL...NRN AND CNTRL IND...SW LOWER MI AND WCNTRL OH... ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS VALLEY...SRN GREAT LAKES...OH VALLEY AND CNTRL APPALACHIAN MTNS OUTSIDE OF THE MODERATE RISK AREA... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS VALLEY...SRN GREAT LAKES REGION...OH VALLEY...SRN AND CNTRL APPALACHIAN MTNS AND MID-ATLANTIC OUTSIDE OF THE ENHANCED RISK AREA... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE MID TO UPPER MS VALLEY...SRN GREAT LAKES REGION...OH AND TN VALLEYS...SRN AND CNTRL APPALACHIAN MTNS AND MID-ATLANTIC OUTSIDE OF THE SLIGHT RISK AREA... ...SUMMARY... WIDESPREAD DAMAGING WIND GUSTS WITH SOME GREATER THAN 70 MILES PER HOUR ALONG WITH TORNADOES AND ISOLATED LARGE HAIL ARE EXPECTED THIS AFTERNOON AND EVENING FROM NORTHEAST IOWA INTO SOUTHERN WISCONSIN...NORTHERN ILLINOIS...SOUTHWEST LOWER MICHIGAN...NORTHERN TO CENTRAL INDIANA AND PARTS OF WESTERN OHIO. A WIND DAMAGE THREAT MAY AFFECT THE UPPER OHIO VALLEY LATE THIS EVENING INTO THE CENTRAL APPALACHIAN MOUNTAINS AND MID-ATLANTIC DURING THE OVERNIGHT PERIOD. ...UPPER MS VALLEY/SRN GREAT LAKES/OH VALLEY/CNTRL APPALACHIANS... AN IMPRESSIVE AND UNSEASONABLE FAST-MOVING SHORTWAVE TROUGH WILL MOVE ESEWD FROM THE NRN PLAINS INTO THE UPPER MS VALLEY TODAY. AHEAD OF THE SYSTEM...A MOIST AND UNSTABLE AIRMASS WILL BE IN PLACE ACROSS THE MID TO UPPER MS VALLEY EXTENDING EWD INTO THE OH AND TN VALLEYS. THIS SETUP WILL BE FAVORABLE FOR A SIGNIFICANT WIND DAMAGE EVENT ACROSS PARTS OF THE UPPER MS VALLEY...SRN GREAT LAKES AND OH VALLEY THIS AFTERNOON AND EVENING. AT THE SFC...A WARM FRONT IS FORECAST TO SETUP FROM NRN IL INTO CNTRL IND DURING THE DAY WITH A WNW-ESE ORIENTED SHARP GRADIENT OF INSTABILITY LOCATED ALONG THE FRONT. A BAND OF CONVECTION MAY BE ONGOING NEAR OR JUST TO THE SOUTH OF THE WARM FRONT FROM IA SEWD INTO CNTRL IL AT THE START OF THE PERIOD. THIS CONVECTION IS FORECAST TO MOVE SEWD INTO THE OH RIVER VALLEY AND MAY HAVE AN ISOLATED WIND DAMAGE THREAT. AS A MODERATELY UNSTABLE WARM SECTOR DEVELOPS BACK TO THE WEST ACROSS THE MID TO UPPER MS VALLEY...AN ASSOCIATED 60 TO 75 KT MID-LEVEL JET WILL APPROACH THE REGION FROM THE WEST. THE PROGRESSIVE MID-LEVEL JET WILL ENHANCE LARGE-SCALE ASCENT AND STRENGTHEN DEEP-LAYER SHEAR ACROSS THE UPPER MS VALLEY MAKING CONDITIONS FAVORABLE FOR ORGANIZED SEVERE STORMS. SFC-BASED THUNDERSTORMS ARE FORECAST TO FIRST INITIATE IN NE IA TO THE NORTHEAST OF A SFC LOW DURING THE MID AFTERNOON. SUPERCELLS WITH LARGE HAIL...WIND DAMAGE AND PERHAPS A STRONG TORNADO WILL BE POSSIBLE WITH THE INITIAL DEVELOPMENT BUT A RATHER QUICK TRANSITION TO LINEAR MODE SHOULD TAKE PLACE. THIS LINE OF STORMS IS FORECAST TO MOVE QUICKLY ESEWD ACROSS NRN IL INTO NCNTRL IND WHERE A BOWING LINEAR MCS APPEARS LIKELY. MODEL SOLUTIONS INCLUDING THE CAMS AND DETERMINISTIC SOLUTIONS SHOW DIFFERING SCENARIOS BUT ARE SUPPORTING THIS IDEA THAT A FAST-MOVING LINEAR MCS WILL TRACK ESEWD ACROSS THE MODERATE RISK AREA. I AM FAVORING A MORE EAST SOUTHEAST MCS TRACK MUCH LIKE THE WRF-NSSL4...NAM AND GFS SOLUTIONS ALONG THE EXPECTED GRADIENT OF MODERATE INSTABILITY FROM NEAR DUBUQUE IA ACROSS SRN PARTS OF THE CHICAGO METRO TO BETWEEN SOUTH BEND AND INDIANAPOLIS IND TO NEAR COLUMBUS OH. A SWATH OF WIND DAMAGE ALONG WITH A CLUSTER OF TORNADOES WILL BE POSSIBLE ALONG THIS CORRIDOR. WIND GUSTS ABOVE 65 KT WILL BE POSSIBLE NEAR THE APEX OF THE BOWING MCS. THE ELONGATED INSTABILITY CORRIDOR PARALLEL TO THE MID-LEVEL FLOW COMBINED WITH A WELL-DEVELOPED FAST-MOVING UPPER-LEVEL SYSTEM WILL MAKE A DERECHO POSSIBLE ACROSS THE REGION FROM LATE AFTERNOON TO THE MID EVENING. A WIND DAMAGE THREAT MAY AFFECT PARTS OF THE UPPER OH VALLEY LATE THIS EVENING INTO PARTS OF THE CNTRL APPALACHIAN MTNS AND MID-ATLANTIC DURING THE OVERNIGHT PERIOD. ..BROYLES/PICCA.. 06/22/2016 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z