SPC AC 140618 DAY 1 CONVECTIVE OUTLOOK RESENT 1 NWS STORM PREDICTION CENTER NORMAN OK 0118 AM CDT TUE OCT 14 2014 VALID 141200Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE ERN GULF COAST STATES...CAROLINAS AND CNTRL APPALACHIAN MTNS... CORRECTED FOR TORNADO GRAPHIC ...SUMMARY... A RISK FOR DAMAGING WIND GUSTS AND A FEW TORNADOES IS EXPECTED TO DEVELOP TODAY AS THUNDERSTORMS MOVE ACROSS THE SOUTHERN APPALACHIAN MOUNTAINS AND INTO THE CAROLINAS. STRONG TO SEVERE THUNDERSTORMS WILL ALSO MOVE EASTWARD ACROSS THE EASTERN GULF COAST STATES TODAY WHERE DAMAGING WIND GUSTS MAY OCCUR AS WELL. MARGINALLY SEVERE THUNDERSTORMS MAY ALSO DEVELOP THIS AFTERNOON ACROSS PARTS OF NORTHERN ILLINOIS SOUTHEASTWARD INTO THE OHIO VALLEY WHERE HAIL AND STRONG WIND GUSTS WILL BE POSSIBLE. ....CAROLINAS/SRN-CNTRL APPALACHIAN MTNS/ERN GULF COAST STATES... AN UPPER-LEVEL LOW AND AN ASSOCIATED UPPER-LEVEL TROUGH WILL MOVE ACROSS THE LOWER TO MID MS VALLEY TODAY. AT THE SFC...A LOW WILL MOVE NEWD ACROSS NRN IL AND INTO THE SRN GREAT LAKES REGION AS A COLD FRONT ADVANCES QUICKLY EWD ACROSS THE MS VALLEY. AHEAD OF THE UPPER-LEVEL SYSTEM...AN IMPRESSIVE 60 TO 75 KT LOW-LEVEL JET WILL TRANSLATE NEWD ACROSS THE UPPER OH VALLEY THIS MORNING WITH THE SRN PART OF THE JET OVER THE SRN APPALACHIAN MTNS. ALONG THE AXIS OF THE LOW-LEVEL JET...A LINE OF THUNDERSTORMS SHOULD BE ONGOING AT THE START OF THE PERIOD FROM FAR ERN KY AND ERN TN SWD ACROSS WRN GA INTO THE FL PANHANDLE WHERE A MARGINAL WIND-DAMAGE THREAT WILL BE POSSIBLE AFTER DAYBREAK. THIS LINE WILL MOVE EWD ACROSS THE SRN AND CNTRL APPALACHIAN MTNS THIS MORNING AND SHOULD REORGANIZE AS SFC TEMPS WARM. REDEVELOPMENT OF THUNDERSTORMS MAY ALSO OCCUR FURTHER TO THE WEST ALONG THE AXIS OF THE LOW-LEVEL JET AROUND MIDDAY. CONCERNING THE SEVERE POTENTIAL...SFC DEWPOINTS FROM NRN FL NNEWD INTO THE CAROLINAS ARE GENERALLY IN THE UPPER 60S AND LOWER 70S F. AS SFC TEMPS WARM TO NEAR 80 F TODAY ACROSS THE ERN GULF COAST STATES AND CAROLINAS...A POCKET OF MODERATE INSTABILITY MAY DEVELOP. MODEL FORECASTS SHOW THE STRONGEST INSTABILITY IN ERN GA...SC AND SRN NC WHERE MLCAPE COULD REACH THE 1000 TO 1500 J/KG RANGE. IN ADDITION...FORECAST SOUNDINGS AT 18Z FOR FLORENCE SC AND FAYETTEVILLE NC SHOW UNIDIRECTIONAL WIND PROFILES WITH 30 TO 35 KT OF 0-6 KM SHEAR. AS SFC TEMPS WARM INTO THE LOWER 80S F...THE MOIST BOUNDARY LAYER AND STRONG LOW-LEVEL FLOW SHOULD RESULT IN A WIND-DAMAGE THREAT WITH A LINE OF STORMS RE-INTENSIFYING AROUND MIDDAY. THE HI-RES WRF-NMM4 MODEL ALSO SUGGESTS THAT DISCRETE CELLS MAY FORM AHEAD OF THE LINE ACROSS THE CAROLINAS EARLY THIS AFTERNOON WHERE A TORNADO THREAT WILL BE POSSIBLE. FURTHER TO THE SOUTH ACROSS ERN GA AND NRN FL...REORGANIZATION OF A LINE OF STRONG THUNDERSTORMS IS EXPECTED THIS AFTERNOON. FORECAST SOUNDINGS IN NRN FL AT 21Z SHOW SBCAPE IN THE 500 TO 1000 J/KG RANGE WITH A VERY MOIST BOUNDARY LAYER AND SFC DEWPOINTS IN THE LOWER 70S F. THIS COMBINED WITH STRONG SPEED SHEAR IN THE BOUNDARY LAYER SHOULD ALSO BE FAVORABLE FOR A WIND-DAMAGE THREAT. ...SRN WI/NRN IL/CNTRL AND NRN IND... AN UPPER-LEVEL LOW WILL MOVE EWD ACROSS THE MID MS VALLEY TODAY AS A SFC LOW MOVES NEWD INTO THE CHICAGO AREA BY EARLY THIS AFTERNOON. SFC DEWPOINTS IN THE LOWER 60S F COMBINED WITH SFC HEATING SHOULD RESULT IN SCATTERED THUNDERSTORM DEVELOPMENT NEAR THE SFC LOW AND SEWD INTO THE OH VALLEY THIS AFTERNOON. THE LEFT EXIT REGION OF A 75 TO 90 KT MID-LEVEL JET WILL OVERSPREAD THE REGION EARLY THIS AFTERNOON AND THIS MAY ALSO ENHANCE CONVECTIVE DEVELOPMENT. FORECAST SOUNDINGS IN NRN IL AND CNTRL IND AT 21Z SHOW SBCAPE VALUES IN THE 500 TO 750 J/KG RANGE WITH MODERATE DEEP-LAYER SHEAR AND 500 MB TEMPS NEAR -15C. THIS ENVIRONMENT COULD RESULT IN A MARGINAL SEVERE THREAT WITH HAIL AND STRONG GUSTY WINDS POSSIBLE WITH THE STRONGER CELLS. ..BROYLES/LEITMAN.. 10/14/2014
Posted on: Tue, 14 Oct 2014 11:07:51 +0000
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