DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0755 AM CDT THU MAY 24 2012 VALID 241300Z - 251200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE UPR MS VLY... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA...FROM THE CNTRL PLNS NEWD INTO THE UPR GRT LKS... ...SYNOPSIS... ACTIVE...ENERGETIC UPR AIR PATTERN WILL CONTINUE OVER THE WRN AND CNTRL U.S. THIS PERIOD AS STRONG CLOSED LOW NOW OFF THE BC CST ADVANCES SE INTO NRN CA...AND DOWNSTREAM SHORTWAVE COMPLEX NOW CONSOLIDATING OVER THE CNTRL RCKYS/CNTRL HI PLNS EJECTS RAPIDLY NE TO THE UPR GRT LKS. COLD FRONT ASSOCIATED WITH THE EJECTING UPR IMPULSE WILL SERVE AS THE MAIN FOCUS FOR STRONG TO SVR TSTMS OVER PARTS OF THE UPR MS VLY TODAY INTO TNGT AS VERY STRONG...VERTICALLY VEERING WIND PROFILES SPREAD NNE AHEAD OF IT. ...MID/UPR MS VLY TO UPR GRT LKS TODAY/TNGT... SATELLITE/RADAR DATA SUGGEST THAT LEAD MEMBER OF CONSOLIDATING SHORTWAVE COMPLEX IS OVER SW MN ATTM. THIS FEATURE SHOULD CONTINUE SHEARING NNEWD THROUGH MUCH OF THE DAY...MAINTAINING AN AREA OF ASCENT ALONG AND W OF STALLED FRONT NOW EXTENDING FROM WRN IA TO NW WI. THIS...AND GRADUALLY INCREASING MOISTURE INFLOW...SHOULD SUPPORT PERSISTENCE OF ASSOCIATED ELEVATED TSTM BAND NOW OVER NRN IA/SE MN THROUGH AT LEAST MIDDAY. BY EARLY TO MID AFTN...LARGE SCALE ASCENT WILL INCREASE OVER IA/SE MN AND WRN WI WITH THE APPROACH/AMPLIFICATION OF UPSTREAM VORT MAX NOW OVER WRN NEB. COUPLED WITH SFC HEATING AND MODEST LOW LVL MOISTURE RETURN...THIS SHOULD FOSTER NEW STORM DEVELOPMENT ALONG THE ERN FRINGE OF THE CONVECTIVE BAND...AND/OR STRENGTHENING OF EXISTING STORMS FROM NRN/ERN IA NNE INTO SE MN AND WRN WI. STRONG...VERTICALLY VEERING WIND FIELDS ALREADY PRESENT OVER THE UPR MS VLY WILL FURTHER STRENGTHEN TODAY AS UPR IMPULSE CONSOLIDATES AND ASSUMES A NEUTRAL TILT. ASSOCIATED DEVELOPMENT OF 70 KT SSWLY 700 MB SPEED MAX ON E SIDE OF SYSTEM /I.E. OVER WRN AND CNTRL WI/ WILL BE FAVORABLE FOR SUSTAINED STORMS AND SUPERCELLS DESPITE SOMEWHAT MODEST BOUNDARY LAYER MOISTURE /SFC DEWPOINTS IN THE UPR 50S TO LWR 60S/. QUESTIONS REMAIN REGARDING DOMINANT CONVECTIVE MODE. ATTM...THE SFC DEWPOINTS ARE GREATEST IN REGION OF STORM-PROCESSED/RAIN-COOLED AIR W OF THE AFOREMENTIONED FRONT AND BENEATH THE ELEVATED TSTMS. ORIENTATION OF THE FRONT PARALLEL TO STRENGTHENING DEEP SSWLY FLOW...LIKELY CONTINUED PRESENCE OF SOMEWHAT DRIER AIR TO ITS EAST...AND WARM SECTOR EML CAP ALL SUGGEST THAT STORMS SHOULD EVOLVE INTO A SSW-NNE SQLN...WITH STRENGTH OF SHEAR SUPPORTING NUMEROUS EMBEDDED LEWPS. ASSOCIATED ROTATING STORMS...SUPERCELLS...AND SMALL BOWS WILL BE CAPABLE OF SWATHS OF DMGG WIND AND TORNADOES. THE TORNADO THREAT SHOULD DIMINISH BY EARLY EVE AS THE SQLN ACCELERATES NEWD INTO NE WI BEYOND AXIS OF LOW LVL MOISTURE RETURN. A CONDITIONAL THREAT FOR SPORADIC SVR WIND WILL...HOWEVER...EXTEND NEWD ACROSS ERN UPR MI AND PERHAPS PARTS OF LWR MI INTO EARLY FRI GIVEN LIKELY DEVELOPMENT OF A STRONG PRESSURE RISE/FALL COUPLET AND REASONABLY BUOYANT LOW LVL AIR STREAMING NWD FROM THE OH VLY. ...CNTRL PLNS LATE TNGT/EARLY FRI... SSWLY LLJ WILL STRENGTHEN OVER MUCH OF KS AND WRN MO LATE TNGT AND EARLY FRI IN RESPONSE TO DIURNAL INFLUENCES AND TO THE CONTINUED ESE ADVANCE OF UPR LOW INTO NRN CA AND THE NRN GRT BASIN. THIS STRENGTHENING WILL OCCUR ATOP TRAILING...SW END OF SAME FRONTAL ZONE THAT WILL CROSS THE UPR MS VLY LATER TODAY. COUPLED WITH THE ARRIVAL OF FAIRLY SUBSTANTIAL MOISTURE RETURN /P.W. AOA 1.25 INCHES/ AND WITH THE CONTINUED PRESENCE OF 40-50 KT WSWLY SHEAR ABOVE THE FRONTAL SFC...SETUP MAY SUPPORT SCTD ELEVATED TSTMS WITH HAIL AND PERHAPS LOCALLY DMG WIND. TEMPORAL STRENGTHENING OF EML CAP /ASSOCIATED WITH ONSET OF LARGE SCALE RIDGING AHEAD OF CA-GRT BASIN LOW/ SUGGESTS THAT AREA OF STORM DEVELOPMENT SHOULD ADVANCE NWD WITH TIME. ...CNTRL/S FL TODAY... SCTD TSTMS EXPECTED THIS AFTN IN ZONE OF STRONG HEATING...HIGH PW...AND UPR DIVERGENCE BENEATH SWLY HIGH LVL JET STREAK. THESE MAY YIELD A FEW INSTANCES OF SVR WIND/HAIL...MAINLY ALONG SEA BREEZE BOUNDARY INTERSECTIONS. ...MID ATLANTIC TODAY... TROPICAL MOISTURE SPREADING NWD/CONVERGING BENEATH RESIDUAL AXIS OF RELATIVELY COOL MID LVL TEMPS MAY SUPPORT A FEW DIURNAL STORMS/STORM CLUSTERS WITH LOCALLY SVR WIND/MARGINALLY SVR HAIL. ..CORFIDI/COHEN.. 05/24/2012 NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z CURRENT UTC TIME: 1504Z (10:04AM), RELOAD THIS PAGE TO UPDATE THE TIME
PUBLIC SEVERE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0647 AM CDT THU MAY 24 2012 ...SEVERE THUNDERSTORMS WITH DAMAGING WINDS AND TORNADOES EXPECTED OVER PARTS OF THE UPPER MISSISSIPPI VALLEY THIS AFTERNOON AND TONIGHT... THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE DEVELOPMENT OF SEVERE THUNDERSTORMS WITH DAMAGING WINDS AND TORNADOES OVER PARTS OF THE UPPER MISSISSIPPI VALLEY THIS AFTERNOON AND TONIGHT. THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE NORTHEASTERN IOWA FAR NORTHWESTERN ILLINOIS A SMALL PART OF THE UPPER PENINSULA OF MICHIGAN FAR SOUTHEASTERN MINNESOTA MUCH OF WISCONSIN ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM...PORTIONS OF THE UPPER MISSISSIPPI VALLEY AND UPPER GREAT LAKES SOUTHWESTWARD INTO KANSAS AND MISSOURI. INTENSIFYING SURFACE LOW PRESSURE WILL TRACK NORTHEASTWARD ALONG A FRONT ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO ONTARIO CANADA TODAY THROUGH TONIGHT. THE COLD FRONT TRAILING SOUTH OF THE LOW WILL SURGE EASTWARD ACROSS PARTS OF EASTERN IOWA AND SOUTHEASTERN MINNESOTA AND INTO WISCONSIN THIS AFTERNOON INTO TONIGHT...AS A STRONG UPPER-LEVEL STORM SYSTEM MOVES NORTHEASTWARD. THUNDERSTORMS WILL DEVELOP WITHIN THE WARM AND MODERATELY HUMID AIR MASS NEAR AND JUST AHEAD OF THE FRONT ACROSS THE UPPER MISSISSIPPI VALLEY BY LATE AFTERNOON AND TRACK EASTWARD INTO TONIGHT. ONE OR MORE FAST-MOVING SQUALL LINES WILL LIKELY ORGANIZE AND BE CAPABLE OF PRODUCING SWATHS OF WIDESPREAD DAMAGING WINDS. TORNADOES...AS WELL AS SEVERE HAIL...WILL ALSO BE POSSIBLE. SEVERE STORMS WILL BE RELATIVELY MORE ISOLATED FARTHER SOUTH ACROSS THE MIDDLE MISSISSIPPI VALLEY INTO THE CENTRAL PLAINS. STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS DEVELOPING SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE WEATHER SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA WEATHER RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.
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