Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 201754
SWOMCD
SPC MCD 201754
PAZ000-MDZ000-VAZ000-DCZ000-WVZ000-NCZ000-202030-

MESOSCALE DISCUSSION 0397
NWS STORM PREDICTION CENTER NORMAN OK
1254 PM CDT MON APR 20 2015

AREAS AFFECTED...CNTRL AND NRN VA...NWRN NC...MD...SRN PA...SWRN NJ

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 201754Z - 202030Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...SCATTERED SEVERE STORMS ARE LIKELY LATER THIS AFTERNOON
WITH HAIL, DAMAGING WINDS AND PERHAPS AN ISOLATED TORNADO.

DISCUSSION...VISIBLE IMAGERY SHOWS CU INCREASING ALONG THE LEE OF
THE APPALACHIANS AS WELL AS INTO CENTRAL VA WHERE STRONG HEATING IS
OCCURRING. DEEPER CU FIELDS ARE ALSO NOTED ALONG A STATIONARY
BOUNDARY FROM SERN PA INTO SRN NJ. A N-S ORIENTED BAND OF CIRRUS IS
ROUGHLY JUXTAPOSED WITH COOLING ALOFT...WITH DEEPER CU INTO THE WELL
MIXED BUT DRIER AIR FROM WRN PA SWWD.

OVER THE NEXT FEW HOURS...STORMS WILL FORM WITHIN THE BROAD LOW
PRESSURE TROUGH...AND ALSO PERHAPS NEAR THE STATIONARY/WARM FRONT.
STRENGTHENING WIND FIELDS WITH THE UPPER TROUGH WILL AID IN NWD
TRANSPORT OF MOISTURE INTO AREAS THAT ARE CURRENTLY STABLE SUCH AS
PA....LEADING TO STORM DEVELOPMENT.

WHILE THE MAIN THREATS WILL BE HAIL AND WIND...LOW-LEVEL SHEAR
AUGMENTATION ACROSS SERN PA...SRN NJ...DE...AND MD...AS WELL AS
LOCALLY HIGHER DEWPOINTS INTO THE 60S F WILL OFFER A MORE FAVORABLE
SETUP FOR AN ISOLATED TORNADO SHOULD CELLS MOVE INTO OR FORM IN THAT
REGION.

..JEWELL/HART.. 04/20/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PHI...AKQ...CTP...LWX...RAH...RNK...PBZ...RLX...

LAT...LON   38397998 39147955 39557923 40327817 40397735 40297684
            40077600 39647596 38797649 38467679 37207824 36278007
            36218119 36538149 36998137 37418077 38397998



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