398 ACUS01 KWNS 130601 SWODY1 SPC AC 130600 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0100 AM CDT MON OCT 13 2014 VALID 131200Z - 141200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF NRN LA...AR...SE MO...NW MS...WRN TN...WRN KY AND FAR SRN IL... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN PLAINS...OZARKS...LOWER MS VALLEY...MID MS VALLEY...CNTRL GULF COAST STATES...TN VALLEY AND OH VALLEY... ...SUMMARY... NUMEROUS STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TODAY AND TONIGHT FROM EAST TEXAS THROUGH THE LOWER AND MIDDLE MISSISSIPPI VALLEY INTO PARTS OF THE TENNESSEE VALLEY...OHIO VALLEY AND GULF COAST STATES. WIDESPREAD DAMAGING WINDS...SOME TORNADOES AND HAIL WILL LIKELY OCCUR. ...LOWER TO MID MS VALLEY... AN IMPRESSIVE UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE SRN PLAINS TODAY AS A 65 TO 80 KT MID-LEVEL JET ROUNDS THE BASE OF THE UPPER-LEVEL TROUGH AND MOVES ACROSS THE ARKLATEX AND OZARKS. AT THE SFC...A LOW WILL MOVE NEWD ACROSS MO AS A COLD FRONT ADVANCES QUICKLY EWD ACROSS ERN OK AND EAST TX. A SQUALL-LINE WILL BE ONGOING AHEAD OF THE FRONT AT THE START OF THE PERIOD FROM SW MO SWD ACROSS WRN AR AND EXTENDING SWWD INTO NE TX. THIS SQUALL-LINE WILL MOVE QUICKLY EWD INTO THE LOWER TO MID MS VALLEY TODAY RESULTING IN WIDESPREAD SEVERE WEATHER. AHEAD OF THE SQUALL-LINE...A WELL-DEVELOPED 50 TO 65 KT LOW-LEVEL JET WILL HELP REINFORCE A CORRIDOR OF LOW-LEVEL MOISTURE EXTENDING NWD ACROSS THE ERN HALF OF AR INTO SERN MO THIS MORNING. SFC DEWPOINTS ALONG THIS CORRIDOR WILL INCREASE INTO THE MID TO UPPER 60S F ALLOWING MODERATE INSTABILITY TO DEVELOP ACROSS PARTS OF SRN AND ERN AR THIS MORNING. WARMING SFC TEMPS DURING THE DAY AND INCREASING LOW-LEVEL MOISTURE SHOULD ENABLE THE SQUALL-LINE TO GRADUALLY INTENSIFY PRODUCING A WIDESPREAD WIND DAMAGE THREAT. A POTENTIAL FOR WIND GUSTS OF GREATER THAN 65 KNOTS WILL EXIST THIS MORNING INTO THIS AFTERNOON AS THE LINE MOVES ACROSS THE MODERATE RISK AREA. TORNADOES MAY ALSO OCCUR WITH ROTATING CELLS EMBEDDED IN THE LINE. THE GREATEST TORNADO THREAT SHOULD DEVELOP ACROSS ERN AR...NW MS AND FAR WRN TN LATE THIS MORNING INTO EARLY AFTERNOON AS SFC TEMPS WARM AND THE LOW- AND MID-LEVEL JETS BECOME COUPLED AHEAD OF THE APPROACHING UPPER-LEVEL TROUGH. ALTHOUGH THE MODERATE RISK AREA IS DRIVEN BY WIND...A STRONG TORNADO OR TWO CAN NOT BE RULED OUT WITH SUPERCELLS THAT CAN FORM IN OR AHEAD OF THE LINE. ...LOWER OH VALLEY/SRN GREAT LAKES... SOUTHWEST MID-LEVEL FLOW WILL BE IN PLACE TODAY ACROSS THE LOWER OH VALLEY AND SRN GREAT LAKES REGION AS A SHORTWAVE RIDGE MOVES NEWD AWAY FROM THE REGION THIS AFTERNOON. AT THE SFC...WINDS WILL BE SSELY...HELPING TO REINFORCE A CORRIDOR OF LOW-LEVEL MOISTURE LOCATED FROM THE MID MS VALLEY NNEWD INTO THE SRN GREAT LAKES REGION WHERE INSTABILITY WILL INCREASE AROUND MIDDAY. NAM FORECASTS SUGGEST THAT SBCAPE COULD REACH THE 1000 TO 1500 J/KG RANGE AS FAR NORTH AS CNTRL INDIANA. ALTHOUGH A SQUALL-LINE WILL MOVE INTO WRN PARTS OF THE REGION THIS MORNING...SOME THUNDERSTORM ACTIVITY MAY DEVELOP WELL AHEAD OF THE LINE AS INSTABILITY INCREASES. FORECAST SOUNDINGS AT SPRINGFIELD IL AND INDIANAPOLIS AT 18Z SHOW 40 KT OF DEEP LAYER SHEAR WITH LOW-LEVEL LAPSE RATES APPROACHING 7.0 C/KM. THIS MAY BE ENOUGH FOR A WIND DAMAGE THREAT WITH THE STRONGER MULTICELLS THIS MORNING. AS A SFC LOW MOVES INTO THE MID MS VALLEY THIS AFTERNOON...THE NRN END OF A SQUALL-LINE IS EXPECTED TO MOVE INTO THE LOWER OH VALLEY. THIS WILL LIKELY RESULT IN A WIND DAMAGE THREAT THIS AFTERNOON WITH A FEW WIND GUSTS GREATER THAN 65 KT POSSIBLE. ...GULF COAST... AN UPPER-LEVEL TROUGH WILL MOVE ACROSS THE SRN PLAINS TODAY AS A COLD FRONT MOVES QUICKLY EWD INTO CNTRL AND ERN TX. A SQUALL-LINE WILL LIKELY BE ONGOING AHEAD OF THE FRONT ACROSS ECNTRL TX AT THE START OF THE PERIOD WITH THIS FEATURE MOVING EWD INTO LA THIS AFTERNOON. FORECAST SOUNDINGS FOR BATON ROUGE AT 18Z SHOW SFC DEWPOINTS NEAR 70 F...MLCAPE NEAR 1500 J/KG AND 45 KT OF 0-6 KM SHEAR. THIS SHOULD SUPPORT A WIND DAMAGE THREAT WITH BOWING LINE SEGMENTS EMBEDDED IN THE SQUALL-LINE. DUE TO THE INSTABILITY...HAIL WILL ALSO BE POSSIBLE WITH THE MORE INTENSE PARTS OF THE LINE. LOW-LEVEL FLOW WILL BE STRONGER WITH NWD EXTENT MAKING THE GREATEST WIND DAMAGE THREAT ACROSS NRN PARTS OF THE REGION FROM CNTRL AND NRN LA EWD INTO CNTRL MS. ..BROYLES/LEITMAN.. 10/13/2014
Posted on: Mon, 13 Oct 2014 10:57:03 +0000
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