[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 281822
SWOMCD
SPC MCD 281822 
MDZ000-PAZ000-DCZ000-VAZ000-WVZ000-OHZ000-282315-

MESOSCALE DISCUSSION 0246
NWS STORM PREDICTION CENTER NORMAN OK
1222 PM CST MON FEB 28 2005

AREAS AFFECTED...VA...D.C...MD...WV AND PA AND ERN OH

CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 

VALID 281822Z - 282315Z

PERIODS OF HVY SNOW APPEAR MORE LIKELY ACROSS MUCH OF CENTRAL/NRN
VA...THE D.C METRO AREA...NRN/CENTRAL MD THROUGH THE LATE AFTERNOON.
THEN THE THREAT FOR HVY SNOW WILL CHANGE TO A POTENTIAL FOR MIXED
PRECIP BEFORE DIMINISHING FROM SOUTH TO NORTH BETWEEN 21-00Z ACROSS
THIS REGION. FURTHER NORTH/WEST...MODERATE TO OCCASIONALLY HVY SNOW
WILL CONTINUE OVER NRN/CNTRL WV THROUGH 21Z WHILE DEVELOPING INTO
SWRN/SCENTRAL PA THROUGH 00Z. HRLY ACCUMULATIONS ABOVE 1 INCH WILL
BE POSSIBLE IN BOTH AREAS...WITH LOCALLY HIGHER SHORT TERM RATES IN
CONVECTIVE BURSTS.

SATELLITE IMAGERY SUGGESTS THAT A STRONG DRY SLOT ON THE BACK SIDE
OF A TRAILING VORT MAX HAS AIDED IN STEEPENING LAPSE RATES AND
CONVECTIVE CLOUD DEVELOPMENT FROM SRN/CENTRAL VA EWD OFFSHORE THE
DELMARVA PENINSULA. 15Z RUC FORECAST SOUNDINGS SUPPORT THIS
...SHOWING 7-7.5 DEG C/KM 700-500 MB LAPSE RATES. THE RECENT COOLING
TRENDS IN IR IMAGERY FURTHER SUPPORT THE TREND TOWARDS INCREASING
VERTICAL MOTION AS UPPER VORT FORCING INTERACTS WITH STRONG LOW
LEVEL WAA PROFILE. DESPITE LIMITED HVY SNOWFALL OVER THE REGION
DURING THE MORNING HOURS...INCREASINGLY CONVECTIVE NATURE OF THE
SNOWFALL AND ORGANIZATION OF SNOWBANDS ALONG AND NORTH OF THE
850-700 MB FRONTAL ZONE MOVING NWD THROUGH SRN VA WILL SUPPORT
GREATER POTENTIAL FOR PERIODS OF HVY SNOWFALL OVER CENTRAL/NRN VA
INTO THE D.C AREA AND NRN/CENTRAL MD THROUGH THE REMAINDER OF THE
AFTERNOON HOURS. AS THE MAIN UPPER VORT PASSES BY...AND BEFORE THE
850 MB WAA CEASES...THERE IS THE POTENTIAL FOR A CHANGEOVER TO
SLEET/FREEZING RAIN ACROSS SRN/ERN PORTIONS OF THE AREA...GENERALLY
ALONG AND JUST SOUTH OF THE I-95 CORRIDOR.

FARTHER WNW...A SECONDARY VORT MAX WHICH WAS WELL DEFINED ON
REGIONAL RADAR MOSAIC CENTERED OVER SWRN WV. THIS WILL CONTINUE TO
SUPPORT INCREASING LIFT/FRONTOGENETIC FORCING AS IT MOVES NWD OVER
NRN WV INTO FAR ERN OH...SWRN/ SCENTRAL PA. MOD TO OCCASIONALLY HVY
SNOW WILL RESULT OVER THIS REGION GENERALLY ABOVE 1000 FT AS FORCING
WILL BE MAXIMIZED IN THE 600-500 MB LAYER COINCIDENT WITH DENDRITIC
SNOW GROWTH.

..CROSBIE.. 02/28/2005

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

ATTN...WFO...PHI...AKQ...CTP...LWX...RNK...PBZ...RLX...CLE...

37757794 39007656 40007601 40507723 40887928 41058087
40088133 38288129 37617922 

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