National Weather Service United States Department of Commerce

Heat Continues for the East and South-Central U.S.; Strong to Severe Storms Across the Mid-Atlantic and Northeast

The extremely dangerous heat wave continues across the East Coast and much of the South-Central U.S. today. Record high temperatures are expected for some areas especially across the Mid-Atlantic where extreme heat risk conditions reside. There is a Slight Risk (level 2 of 5) of severe thunderstorms today for the northern Mid-Atlantic into portions of southern New England. Read More >

Day 1 Convective Outlook issued at 0618 UTC 14 October 2014

   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

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