[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 221900
SWOMCD
SPC MCD 221900 
MAZ000-NHZ000-RIZ000-CTZ000-NYZ000-VTZ000-NJZ000-PAZ000-DEZ000-MDZ000-222330-

MESOSCALE DISCUSSION 0117
NWS STORM PREDICTION CENTER NORMAN OK
0100 PM CST SAT JAN 22 2005

AREAS AFFECTED...ERN PA/SE NY/CT/WRN MA/NJ/DE/ERN MD

CONCERNING...HEAVY SNOW 

VALID 221900Z - 222330Z

HEAVY SNOW TO CONTINUE TO EXPAND EWD AND INTENSIFY ACROSS SE
NY/CT/WRN MA AND MUCH OF NJ/DE THROUGH 21Z-00Z. RATES OF 1.0-1.5
IN/HR WILL BE COMMON...WITH LOCALLY HIGHER RATES POSSIBLE.

WATER VAPOR/INFRARED SATELLITE IMAGERY DEPICTS FAST MOVING SHORTWAVE
TROUGH ADVANCING ESE OVER THE OHIO VALLEY...WITH DRY SLOT SURGING
EWD ACROSS WRN PA/WRN MD AT 18Z. SURFACE ANALYSIS FEATURES 1000 MB
SFC LOW INVOF THE OH/PA BORDER...WITH 2-3 MB/HR PRESSURE FALLS
CENTERED ACROSS THE DELMARVA...AN INITIAL SIGN OF MID ATLANTIC
COASTAL LOW DEVELOPMENT.

12Z PIT/IAD RAOBS AUGMENTED BY REGIONAL WSR-88D VADS REFLECTIVE OF
WAA REGIME AHEAD OF UPPER TROUGH...WITH 50-60 KTS OF SWLY FLOW
PRESENT IN 1-4 KM LAYER. PROGRESSIVELY EWD FOCUS OF THIS STRONG WAA
REGIME/285K-300K ISENTROPIC ASCENT SUGGESTS MDT/HEAVY SNOW TO EXPAND
EWD ACROSS SE NY/CT/WRN MA/NJ/DE PRIOR TO 00Z. GIVEN STRONG FORCING
FOR ASCENT...18Z RUC SOUNDINGS PORTRAY A QUICK/DEEP SATURATION OF
VERTICAL COLUMN ACROSS MUCH OF THIS CORRIDOR...WITH FAVORABLE
DENDRITIC GROWTH LAYER CONDUCIVE TO HEAVY SNOWFALL. GIVEN ARCTIC
AIRMASS IN PLACE...SNOW TO LIQUID WATER RATIOS OF 20:1 OR HIGHER
WILL FURTHER CONTRIBUTE TO HEAVY SNOW AMOUNTS.

ACROSS FAR ERN MD/DE/SRN NJ...CONSISTENT WITH SFC OBSERVATIONAL
TRENDS AND LOW LEVEL WARMING OBSERVED BETWEEN 12Z-18Z WAL
RAOBS...18Z BASED RUC SOUNDINGS SUGGEST INITIAL MDT/OCNLY HEAVY SNOW
WILL CHANGE-OVER TO RAIN AROUND/AFTER 21Z.

..GUYER.. 01/22/2005

...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...BOX...OKX...ALY...PHI...BGM...AKQ...CTP...LWX...

39457694 40307643 41647610 42947548 43217451 43247355
42897200 42247160 40867208 40407381 39827433 39317476
38537578 38847683 

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