Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS11 KWNS 212325
SWOMCD
SPC MCD 212324
NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-WVZ000-220330-

MESOSCALE DISCUSSION 0089
NWS STORM PREDICTION CENTER NORMAN OK
0524 PM CST SAT FEB 21 2015

AREAS AFFECTED...PORTIONS OF FAR NRN VA...CNTRL MD...SERN PA...AND
NWRN NJ

CONCERNING...HEAVY SNOW

VALID 212324Z - 220330Z

SUMMARY...MODERATE TO HEAVY SNOW WILL CONTINUE THROUGH 02-03Z BEFORE
DIMINISHING LATER THIS EVENING. SNOWFALL RATES UP TO 1 INCH PER HOUR
WILL CONTINUE TO BE POSSIBLE.

DISCUSSION...23Z REGIONAL WSR-88D MOSAIC INDICATES AN EXPANSIVE AREA
OF MDT-HVY PCPN CONTINUES TO EXPAND NEWD ACROSS THE MID-ATLANTIC AND
INTO THE NORTHEAST/NEW ENGLAND. THIS EXPANSION IS IN RESPONSE TO
CONTINUED STRONG ISENTROPIC ASCENT ON THE NOSE OF A 75-KT LLJ.
REGIONAL VWP DATA ARE CHARACTERIZED BY LONG CYCLONICALLY LOOPING
HODOGRAPHS...INDICATIVE OF THE ROBUST WAA ONGOING ACROSS THE REGION.
IN CONCERT WITH LARGE-SCALE FORCING FOR ASCENT FROM AN APPROACHING
MID-LEVEL SHORTWAVE TROUGH...THIS STRONG WAA WILL SUPPORT CONTINUED
SNOWFALL RATES UPWARDS OF 1 INCH PER HOUR ACROSS THE MCD AREA.

THE SNOW WILL LIKELY MIX WITH AND CHANGE OVER TO SLEET/FZRA ACROSS
SRN/ERN PORTIONS OF THE AREA OVER THE NEXT FEW HOURS...AS THE WARM
NOSE ALOFT CONTINUES TO SPREAD NE. THE 12Z WRF-NSSL IS IN AGREEMENT
WITH THIS REASONING...AND ITS DEPICTION OF THE P-TYPE TRANSITION IS
WELL SUPPORTED BY CURRENT DUAL-POLARIZATION DATA/MPING REPORTS. BY
LATE THIS EVENING INTO EARLY TONIGHT...PCPN WILL GRADUALLY DECREASE
IN INTENSITY...AS FORCING FOR ASCENT WEAKENS AND DEPARTS TO THE
E/NE.

..PICCA/EDWARDS.. 02/21/2015

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

ATTN...WFO...PHI...CTP...LWX...

LAT...LON   39287647 38907731 38647780 39157796 39697735 40137662
            40747547 40927495 40987471 40797449 40217476 39647558
            39257646 39287647



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