[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 281731
SWOMCD
SPC MCD 281730 
NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-282230-

MESOSCALE DISCUSSION 0245
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CST MON FEB 28 2005

AREAS AFFECTED...NJ...ERN PA AND SERN NY...LONG ISLAND

CONCERNING...HEAVY SNOW 

VALID 281730Z - 282230Z

A BAND OF MODERATE SNOW WILL CONTINUE TO DEVELOP NWD ACROSS SRN
NJ...ERN PA THROUGH THE MID AFTERNOON HOURS AND BEGIN TO POSE A
THREAT FOR HVY SNOW AS IT MOVES NWD INTO NRN NJ/LONG ISLAND AND THE
NYC AREA. THUS HOURLY RATES AROUND 1 INCH WILL BE POSSIBLE WITH THIS
BAND WITHIN THE NEXT FEW HOURS. SNOW WILL LIKELY MIX OR CHANGE OVER
TO SLEET AND/OR COLD RAIN ACROSS ERN PORTIONS OF THE AREA AFTER
INITIAL PASSAGE OF THIS BAND.

MID LEVEL FRONTOGENESIS CENTERED AROUND 600 MB AND CONTINUED STRONG
LOW-MID LEVEL ISENTROPIC LIFT WILL CONTINUE TO SUPPORT A 20-30 NM
WIDE E-W BAND OF MOD SNOW AS IT MOVES NWD THROUGH NJ AND ERN PA AND
EVENTUALLY INTO LONG ISLAND/SERN NY. DESPITE THE DEEP DRY LAYER
EVIDENT ON THE 12Z OKX SOUNDING... PRECIPITATION FALL SHOULD RAPIDLY
SATURATE THIS LAYER. AS SECONDARY UPPER VORT MAX MOVES NWD THROUGH
VA...INCREASINGLY STRONG FRONTOGENETIC FORCING WILL LEAD TO HVY
SNOWFALL RATES WITHIN THIS BAND OF SNOW. CURRENT FORWARD MOTION OF
THIS BAND AROUND 15 MPH SUGGESTS MOST AREAS WILL EXPERIENCE ABOUT 2
HOURS OF SNOWFALL RATES UP TO 1 INCH/HR. ADDITIONALLY...THIS PRESENT
FORWARD MOTION WOULD ALLOW FOR THE THREAT OF HVY SNOW TO BEGIN
MOVING INTO THE NYC METRO AREA AROUND 21Z.

DUE TO THE STRONG WARM ADVECTION REGIME IN THE 1-3 KM LAYER...SOME
OF THE SNOW MAY CHANGE OVER TO SLEET AFTER THE INITIAL FRONTOGENETIC
HEAVY SNOW BAND MOVES THROUGH. AREAS MOST LIKELY TO SEE A MIX OF
SLEET/SNOW WILL BE ALONG THE I-95 CORRIDOR. A CHANGE OVER TO RAIN
APPEARS MOST LIKELY ALONG THE IMMEDIATE COASTAL AREAS OF SRN NJ
WHERE SFC TEMPERATURES SHOULD REMAIN ABOVE FREEZING.

..CROSBIE.. 02/28/2005

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

ATTN...WFO...OKX...PHI...BGM...CTP...

39807410 40667333 41127404 41227518 40687573 40187590
39847603 39237486 

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