DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 AM CDT MON JUN 08 2015
VALID 081300Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FROM
TN/KY NEWD TO PARTS OF PA AND SRN NY...
...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLGT
RISK...FROM AR TO PARTS OF THE GREAT LAKES EWD TO THE MID ATLANTIC
AND NY...
...THERE IS A MRGL RISK OF SVR TSTMS FOR THE SRN HIGH PLAINS...
...SUMMARY...
SEVERE THUNDERSTORMS WITH DAMAGING WINDS...ISOLATED LARGE HAIL...AND
PERHAPS A TORNADO OR TWO...WILL BE POSSIBLE TODAY INTO THIS EVENING
FROM TENNESSEE AND KENTUCKY NORTHEASTWARD TO
MARYLAND...PENNSYLVANIA...AND PARTS OF SOUTHERN NEW YORK. OTHER
STRONG STORMS WILL BE POSSIBLE ACROSS PARTS OF THE UPPER GREAT
LAKES...AS WELL AS THE SOUTHERN HIGH PLAINS.
...TN/KY AREA THIS AFTERNOON/EVENING...
A NRN STREAM SHORTWAVE TROUGH WILL CONTINUE TO MOVE ESEWD FROM THE
UPPER GREAT LAKES AND MS VALLEY TO THE APPALACHIANS BY THE END OF
THE PERIOD. THIS WAVE ALOFT WILL BE ACCOMPANIED BY A WEAK SURFACE
COLD FRONT THAT WILL REACH THE CORRIDOR FROM SRN LOWER MI SWWD
ACROSS INDIANA TO WRN KY...NRN AR...AND CENTRAL OK BY THIS EVENING.
WEAKENING CONVECTIVE CLUSTERS WITH CONVECTIVE OUTFLOW PRECEDE THE
FRONT FROM SE MO TO SRN IL AND THE INDIANA/KY BORDER. THIS MORNING
CONVECTION WILL LIKELY CONTINUE TO WEAKEN...LEAVING A DIFFUSE
OUTFLOW BOUNDARY TODAY ACROSS WRN AND NRN KY. DESTABILIZATION IS
ALSO POSSIBLE FROM THE WSW IN THE WAKE OF THIS MORNING
CONVECTION...IMMEDIATELY IN ADVANCE OF THE WEAK SYNOPTIC COLD FRONT.
THE REMNANT OUTFLOW AND/OR COLD FRONT WILL SERVE TO FOCUS
THUNDERSTORM DEVELOPMENT THIS AFTERNOON...WHERE THE STRONGER SURFACE
HEATING AND BOUNDARY LAYER DEWPOINTS IN THE UPPER 60S TO LOWER 70S
WILL CONTRIBUTE TO MLCAPE VALUES OF 1500-2500 J/KG. DEEP-LAYER
VERTICAL SHEAR WILL INCREASE SOME DURING THE AFTERNOON ACROSS KY/TN
WITH THE APPROACH OF THE MIDLEVEL TROUGH...WITH FORECAST HODOGRAPHS
SUGGESTING A MIX OF ORGANIZED MULTICELL CLUSTERS/LINE SEGMENTS AND
EMBEDDED SUPERCELLS AS THE PREFERRED CONVECTIVE MODES. AS
SUCH...DAMAGING GUSTS WILL BE THE MAIN SEVERE STORM THREAT...WITH
IS0LATED LARGE HAIL WILL ALSO BE POSSIBLE WITH THE STRONGER
UPDRAFTS. THE TORNADO RISK APPEARS TO BE MORE IN QUESTION GIVEN
SOMEWHAT MARGINAL LOW-LEVEL SHEAR AND POTENTIALLY MESSY CONVECTIVE
MODES.
...CENTRAL APPALACHIANS TO SRN NY THIS AFTERNOON/EVENING...
LOW-LEVEL MOISTURE ADVECTION FROM THE S/SW IS UNDERWAY FROM OH/WV
INTO WRN NY. THERE IS LESS PRE-FRONTAL CONVECTION APPROACHING THIS
AREA COMPARED TO THE LOWER OH VALLEY...BUT BOUNDARY LAYER DEWPOINTS
ARE ALSO LOWER /LOW-MID 60S/. AFTERNOON BUOYANCY WILL BE LARGEST ON
THE ERN FRINGE OF CLOUD DEBRIS OVERSPREADING PA/NY FROM THE W...WITH
THE MORE PROBABLY CORRIDOR FOR SEVERE STORM DEVELOPMENT RUNNING FROM
CENTRAL/ERN PA INTO S CENTRAL NY BY MID AFTERNOON. DAMAGING WINDS
WILL BE THE PRIMARY RISK. VERTICAL SHEAR WILL BE SUFFICIENTLY
STRONG TO SUPPORT SUPERCELLS...AND A TORNADO OR TWO WILL BE POSSIBLE
IF SUSTAINED SUPERCELLS CAN DEVELOP IN THE ZONE OF STRONGER
LOW-LEVEL SHEAR NEAR THE WARM FRONT THIS AFTERNOON/EVENING.
...WI/NRN IL TO SRN LOWER MI THIS AFTERNOON...
THE PRIMARY NRN STREAM TROUGH WILL ROTATE OVER THE LAKE MI AREA BY
LATE AFTERNOON. LINGERING LOW-LEVEL MOISTURE AND COOLER MIDLEVEL
TEMPERATURES WITH THE TROUGH WILL SUPPORT SUFFICIENT SURFACE-BASED
BUOYANCY FOR A MARGINAL WIND/HAIL RISK WITH ESEWD/SEWD-MOVING STORM
CLUSTERS AND LINE SEGMENTS...MAINLY THIS AFTERNOON/EVENING.
