[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 210609
SWOMCD
SPC MCD 210609 
MAZ000-NHZ000-RIZ000-CTZ000-NYZ000-VTZ000-NJZ000-PAZ000-211015-

MESOSCALE DISCUSSION 0184
NWS STORM PREDICTION CENTER NORMAN OK
1209 AM CST MON FEB 21 2005

AREAS AFFECTED...MA...CT...RI...SRN NH...SRN VT...ERN/SERN NY...NERN
PA...AND NRN NJ

CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 

VALID 210609Z - 211015Z

WIDESPREAD MODERATE TO LOCALLY HEAVY SNOW WILL SPREAD EWD ACROSS
CENTRAL/SRN NEW ENGLAND DURING THE REMAINDER OF THE OVERNIGHT
PERIOD. SNOWFALL RATES AROUND 1 IN/HR ARE EXPECTED FOR A PERIOD OF
SEVERAL HOURS. ONGOING PRECIPITATION ACROSS ERN/SERN NY...NERN
PA...AND NRN NJ WILL REMAIN PREDOMINATELY SNOW...THOUGH SOME MIX
WITH OR CHANGE TO SLEET/RAIN IS POSSIBLE NEAR THE COAST OF NRN
NJ/LONG ISLAND TOWARD DAYBREAK. 

AT 0530Z...STRONG 850-700MB WARM ADVECTION OCCURRING EAST OF PRIMARY
1006MB LOW OVER SERN MI WILL DEVELOP NEWD TO ALONG AN AXIS FROM ALB
TO ACK BY 21/15Z. PHASING OF SRN STREAM IMPULSE WITH TROUGH
TRAVERSING THE CENTRAL GREAT LAKES REGION DURING SUNDAY AFTERNOON
HAS RESULTED IN ENTRAINMENT OF STEEP MID-LEVEL LAPSE RATES AND AMPLE
MOISTURE IN ADVANCE OF SHORTWAVE TROUGH AXIS. THE PRE-EXISTING
ARCTIC HIGH OVER NRN ME HAS ESTABLISHED FAVORABLE LARGE-SCALE
ISENTROPIC LIFT ACROSS THE DISCUSSION AREA...WHICH IS BEING ENHANCED
BY FAST MOTION OF SYSTEM AND 50-60KT 850MB FLOW PERPENDICULAR TO
BAROCLINIC ZONE. 

PRECIPITATION EFFICIENCY SHOULD BE ENHANCED BY VERY DEEP...SATURATED
DENDRITE GROWTH LAYER /-12C TO -16C/ WHICH IS EVIDENT IN RUC MODEL
SOUNDINGS ACROSS ERN NY INTO CENTRAL NEW ENGLAND THROUGH THE
REMAINDER OF THE OVERNIGHT PERIOD. INITIAL DRY BOUNDARY LAYER
CONDITIONS SHOULD BE OVERCOME RATHER QUICKLY GIVEN STRENGTH OF
FORCING AND MOISTURE AVAILABILITY. SOME MESOSCALE ENHANCEMENT TO
LIFT AND PRECIPITATION GENERATION IS OCCURRING ON LEADING EDGE OF
PRECIPITATION SHIELD AS DEFORMATION ZONE PUSHES INTO ARCTIC RIDGE
ACROSS ME/NOVA SCOTIA. THIS SHOULD ACT TO QUICKEN LOW-LEVEL
MOISTENING. ANTICIPATE A RATHER UNIFORM AND WIDESPREAD REGION OF
MODERATE TO ISOLATED HEAVY SNOW DEVELOPING EWD INTO CENTRAL/SRN NEW
ENGLAND THROUGH THE EARLY MORNING HOURS.  

A SECONDARY PRESSURE FALL CENTER OF 2.5MB/2HR IS NOTED ACROSS THE
DELMARVA WHERE SURFACE TROUGH/WARM FRONT APPEARS TO BE DEVELOPING.
THE 00Z NAM SUGGESTS SECONDARY CYCLONE DEVELOPMENT WILL TAKE PLACE
TOWARD DAYBREAK EAST OF NJ. LOW-LEVEL ELY/SELY ONSHORE FLOW MAY
PRODUCE SHALLOW ABOVE FREEZING LAYER ALONG THE COAST OF NRN NJ/LONG
ISLAND CAUSING A LOCALIZED MIX OR CHANGE TO RAIN TOWARD 12Z.

..BANACOS.. 02/21/2005

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

...NOTICE...
SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A 
SCHEDULED BASIS...FOUR TIMES A DAY...BETWEEN 00-01 UTC...
06-07 UTC...12-13 UTC...AND 18-19 UTC AS SIGNIFICANT SHORT
RANGE WINTER WEATHER EVENTS UNFOLD.  THIS SCHEDULE WILL BE
USED FROM DECEMBER 1 THROUGH FEBRUARY 28.

ATTN...WFO...GYX...BOX...OKX...ALY...PHI...BGM...

41196980 40577205 40347433 40597515 41177569 41717583
42367589 42847567 43187512 43167307 43107139 42937049
42256971 

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