ZCZC SPCSWOMCD ALL
ACUS11 KWNS 221632 
SPC MCD 221632 
NYZ000-CTZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-WVZ000-NCZ000-221830-

MESOSCALE DISCUSSION 0416
NWS STORM PREDICTION CENTER NORMAN OK
1132 AM CDT WED APR 22 2015

AREAS AFFECTED...FAR NWRN NC...CNTRL AND NRN VA...CNTRL MD...SERN
PA...NJ...DE...FAR SERN NY...FAR SWRN CT

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 221632Z - 221830Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORMS ARE BEGINNING TO INITIATE ACROSS WESTERN
MD/NORTHERN VA WITH A THREAT FOR ISOLATED DAMAGING WIND GUSTS
THROUGH THE AFTERNOON...BUT LIMITED MOISTURE SHOULD KEEP THE
COVERAGE OF SEVERE WIND/HAIL BELOW WATCH THRESHOLDS.

DISCUSSION...A BAND OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS
STRETCHES FROM CNTRL NY TO ERN KY AHEAD OF AN ELONGATED SHORTWAVE
TROUGH AND ATTENDANT COLD FRONT ROTATING AROUND A CLOSED UPPER LOW
OVER WRN ONTARIO. STRONG HEATING IS ONGOING AHEAD OF THIS BAND
UNDERNEATH MID-LEVEL LAPSE RATES OF 7.0 TO 7.5 C/KM. THE MAIN
LIMITING FACTOR REMAINS MODEST BOUNDARY-LAYER MOISTURE. SURFACE
DEWPOINTS ARE IN THE MID 30S TO LOW 40S AND MAY DECREASE SOMEWHAT
THROUGH THE AFTERNOON WITH STRONG HEATING. NONETHELESS...MUCAPE IS
EXPECTED TO REACH VALUES OF 100-400 J/KG AS CONVECTIVE TEMPERATURES
ARE REACHED IN THE MD AREA. STRONG WESTERLY FLOW 1-3KFT AGL AND A
DRY SUB-CLOUD WELL-MIXED BOUNDARY LAYER SHOULD SUPPORT THE POTENTIAL
FOR ISOLATED STRONG-TO-MARGINALLY SEVERE WIND GUSTS IN THE MORE
ORGANIZED LINE SEGMENTS. HOWEVER...THE COVERAGE OF THE WIND GUSTS
REACHING SEVERE CRITERIA IS EXPECTED TO REMAIN ISOLATED ENOUGH TO
PRECLUDE A WATCH AT THIS TIME.

..CONIGLIO/GLEASON/HART.. 04/22/2015

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

ATTN...WFO...OKX...ALY...PHI...BGM...AKQ...CTP...LWX...RAH...
RNK...GSP...

LAT...LON   40947582 41417523 41617467 41827405 41757323 41317312
            39797442 38097628 37077801 36397949 35958082 36358159
            37308082 38877858 39917725 40947582 

NNNN