SPC AC 272000

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0300 PM CDT SUN JUL 27 2014

   VALID 272000Z - 281200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
   LAKES...OH VALLEY...TN VALLEY...SRN TO CNTRL APPALACHIAN MTNS...THE
   MID-ATLANTIC AND SRN NEW ENGLAND...

   ...SUMMARY...
   SEVERE THUNDERSTORMS ARE EXPECTED TODAY INTO TONIGHT ACROSS MUCH OF
   THE OHIO VALLEY AND MID ATLANTIC COAST REGION.  THE MOST SIGNIFICANT
   SEVERE WEATHER THREAT AREA WILL BE ACROSS EASTERN
   KENTUCKY...SOUTHERN OHIO...SOUTHWESTERN WEST VIRGINIA...AND
   SOUTHWESTERN VIRGINIA THIS AFTERNOON.  A ISOLATED STRONG TORNADO
   WILL BE POSSIBLE ALONG WITH DAMAGING WINDS AND VERY LARGE HAIL.

   SEVERAL CHANGES HAVE BEEN MADE TO THE OUTLOOK FOR THIS ISSUANCE. THE
   FIRST CHANGE TO THE OUTLOOK IS TO SHIFT THE 10 PERCENT TORNADO
   PROBABILITY AND SIGNIFICANT HATCHED AREA SWD TO COVER SE KY...FAR
   SRN WV...WRN VA...ERN TN AND FAR WRN NC. THE SUPERCELLS CURRENTLY IN
   SE KY WILL MOVE INTO THIS AREA OVER THE NEXT 1 TO 4 HOURS. THE
   SECOND CHANGE TO THE OUTLOOK IS TO REMOVE THE 5 PERCENT TORNADO FOR
   MUCH OF THE ERN HALF OF VA...NERN NC...NJ AND NE PA WHERE
   INSTABILITY IS WEAKER THAN FORECAST. HAVE MAINTAINED THE 5 PERCENT
   TORNADO PROBABILITY ACROSS THE SWRN HALF OF PA INTO MD AND NJ WHERE
   AN AXIS OF MODERATE TO STRONG INSTABILITY IS SETTING UP. HAVE ADDED
   PARTS OF SERN LOWER MI INTO THE 5 PERCENT TORNADO PROBABILITY WHERE
   INSTABILITY AND LOW-LEVEL SHEAR APPEARS STRONG ENOUGH FOR AN
   ISOLATED TORNADO THREAT. THE THIRD CHANGE TO THE OUTLOOK IS TO
   EXPAND THE 30 PERCENT WIND DAMAGE PROBABILITY INTO SERN LOWER MI AND
   ESEWD ACROSS THE MID-ATLANTIC REGION TO ALIGN WITH THE AXIS OF
   STRONGEST INSTABILITY. THE FOURTH CHANGE TO THE OUTLOOK IS TO ALIGN
   THE SLIGHT RISK AREAS WRN EDGE TO THAT A COLD FRONT IN NRN IND WHERE
   STRONG TO POTENTIALLY SEVERE THUNDERSTORMS ARE DEVELOPING. THE FIFTH
   CHANGE TO THE OUTLOOK IS TO ADD AREAS OF SW NM AND ECNTRL AZ INTO
   THE 5 PERCENT WIND DAMAGE PROBABILITY WHERE MORE INSTABILITY HAS
   DEVELOPED THIS AFTERNOON.

   ..BROYLES.. 07/27/2014

   .PREV DISCUSSION... /ISSUED 1120 AM CDT SUN JUL 27 2014/

   ...CENTRAL APPALACHIANS...
   WIDESPREAD CLOUDS AND PRECIPITATION ACROSS EASTERN KY AND WESTERN WV
   HAVE INCREASED UNCERTAINTY OF A WIDESPREAD SEVERE WEATHER EVENT. 
   THEREFORE HAVE REMOVED THE MDT RISK AREA...BUT HAVE MAINTAINED
   ENHANCED PROBABILITIES OF TORNADOES/HAIL/WIND ACROSS THIS REGION.

   A STRONG PROGRESSIVE SHORTWAVE TROUGH OVER THE UPPER MS VALLEY WILL
   CONTINUE TO TRACK SOUTHEASTWARD INTO THE OH VALLEY AND CENTRAL
   APPALACHIANS TODAY AND TONIGHT.  RATHER STRONG LARGE SCALE FORCING
   FOR ASCENT AND DESTABILIZATION WILL OCCUR AHEAD OF THE
   TROUGH...RESULTING IN A RATHER LARGE AREA OF POTENTIAL SEVERE
   WEATHER.  THE MOST FOCUSED AREA OF CONCERN IS OVER PARTS OF
   KY/OH/WV.

   ...KY/OH/WV THIS AFTERNOON AND EVENING...
   WIDESPREAD CLOUDS AND PRECIPITATION HAVE BEEN OCCURRING THIS MORNING
   OVER MUCH OF CENTRAL/EASTERN KY INTO WESTERN WV.  THIS REGION OF
   CONVECTION WAS NOT HANDLED WELL BY 12Z NAM INITIALIZATION OR ANY
   MESOSCALE MODELS THAT USE THAT INPUT.  THIS RESULTS IN CONSIDERABLE
   UNCERTAINTY WHETHER WIDESPREAD SEVERE STORMS CAN DEVELOP OVER
   SOUTHERN OH THIS AFTERNOON AND SPREAD ACROSS THE AREA EARLIER
   DEPICTED IN A MDT RISK.  DUE TO INCREASING DOUBT...HAVE REMOVED THE
   45 PERCENT WIND AREA...BUT HAVE MAINTAINED OTHER ENHANCED
   PROBABILITIES FOR THIS REGION.

   AT 15Z...THE PRIMARY OUTFLOW BOUNDARY FROM THE MORNING STORMS
   EXTENDS FROM WEST-CENTRAL KY TO SOUTH JKL.  THIS BOUNDARY WILL
   LIKELY BE THE FOCUS FOR SEVERE STORMS THIS AFTERNOON AND EVENING. 
   FORECAST SOUNDINGS ALONG THIS CORRIDOR APPEAR FAVORABLE FOR
   SUPERCELLS CAPABLE OF VERY LARGE HAIL AND ISOLATED TORNADOES. 
   BOWING SEGMENTS ARE ALSO POSSIBLE WITH A DAMAGING WIND THREAT. 
   STORMS MAY PERSIST THROUGH THE EVENING ACROSS THE CREST OF THE
   APPALACHIANS INTO PARTS OF VA AND NORTHERN NC.

   ...LOWER MI/OH/PA...
   STRONG HEATING IS OCCURRING OVER MUCH OF OH INTO WESTERN PA...WHERE
   AFTERNOON HIGH TEMPERATURES IN THE 80S ARE EXPECTED.  MODERATE
   INSTABILITY WILL DEVELOP...ALONG WITH SCATTERED AFTERNOON
   THUNDERSTORMS.  COOL TEMPERATURES ALOFT AND STEEP LAPSE
   RATES...COMBINED WITH FAVORABLE EFFECTIVE SHEAR PROFILES...WILL
   PROMOTE SUPERCELL STORM STRUCTURES CAPABLE OF HAIL AND DAMAGING
   WINDS.

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