[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 021908
SWOMCD
SPC MCD 021908 
MEZ000-NHZ000-VTZ000-MAZ000-NYZ000-022345-

MESOSCALE DISCUSSION 0011
NWS STORM PREDICTION CENTER NORMAN OK
0108 PM CST SUN JAN 02 2005

AREAS AFFECTED...NRN/ERN NY...WRN/CENTRAL MA...MOST OF VT/NH AND ME

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 021908Z - 022345Z

A MIX OF SLEET/FREEZING RAIN AND SNOW WILL OVERSPREAD THE REGION
THROUGH 00Z. THE LEADING EDGE OF PRECIPITATION SHOULD REACH ERN ME
BY 00Z. SNOW WILL BE THE PREDOMINANT PTYPE OVER NRN/CENTRAL
ME...WITH A MIX OF SLEET AND FREEZING RAIN ACROSS THE REST OF THE
REGION. THE HEAVIEST ACCUMULATIONS OF SLEET/FREEZING RAIN WILL OCCUR
OVER NRN NY...NRN VT/NRN NH INTO MUCH OF SRN ME...WHERE HRLY LIQUID
EQUIVALENT ACCUMULATION RATES FROM 0.05-0.10 INCH WILL BE POSSIBLE.
FARTHER SOUTH OVER ECENTRAL NY...SRN VT/NH AND WRN/CNTRL MA...LESSER
HRLY AMOUNTS FROM 0.01-0.05 INCH WILL OCCUR.

RECENT VIS IMAGERY SHOWS THE CLOUD DECK IN THE 850-700 MB LAYER
CONTINUES TO RAPIDLY ADVANCE EWD IN A STRONG WARM ADVECTIVE REGIME
ASSOCIATED WITH A PROGRESSIVE SHORTWAVE TROUGH MOVING ACROSS ONTARIO
CANADA/ERN GREAT LAKES. LOW LEVEL SATURATION WILL REMAIN AN ISSUE
FOR MORE SIGNIFICANT WINTER MIXED PRECIP ACROSS SRN PORTIONS OF THE
MCD AREA...WHERE MID LEVEL FORCING WILL REMAIN WEAKER...AND DRY LOW
LEVELS WILL LIMIT THE ONSET AND DEGREE OF PRECIPITATION
ACCUMULATION. FURTHER NORTH...THE DEGREE OF ISENTROPIC ASCENT
THROUGH 700 MB COMBINED WITH STRONGER MID LVL DEFORMATION WILL
SUPPORT HIGHER PRECIPITATION AMOUNTS ONCE LOW LEVEL SATURATION
OCCURS. IN BOTH AREAS...DRY AIR IN THE LOW LEVELS BENEATH ELEVATED
WARM LAYER WILL SUPPORT PRECIPITATION BEGINNING AS SLEET. AS LOW
LEVEL SATURATION ENSUES...ALONG WITH ADDITIONAL WARMING IN THE
925-850 MB LAYER...PTYPE WILL CHANGE OVER TO FREEZING RAIN FROM
SW-NE ACROSS THE REGION. CURRENT SFC TEMP AND RADAR TRENDS INDICATE
THAT THE LEADING EDGE OF ACCUMULATING SLEET WILL BEGIN OVER NH/SRN
ME AND CNTRL MA BY 22Z...WITH A CHANGEOVER TO FREEZING RAIN FROM
SW-NE OVER VT AND WRN MA DURING THE SAME TIME FRAME. AS LOW LEVEL
WARMING CONTINUES UPSTREAM...A CHANGE OVER TO RAIN OVER PORTIONS OF
NRN/ERN NY IS ANTICIPATED AS WELL.

FURTHER NORTH ACROSS NRN/CENTRAL ME...THE STRENGTH OF THE LOW-MID
LEVEL WAA WILL ENHANCE MID LEVEL FRONTOGENESIS FROM SRN QUEBEC INTO
NRN ME BETWEEN 20-22Z....PROMOTING MDT SNOW DEVELOPMENT FROM W-E
THROUGH 00Z. MAIN LIMITING FACTOR FOR HVY SNOW WILL BE THE NECESSARY
SATURATION IN THE SFC-850 MB LAYER AND OVERALL MODEST MID LEVEL
FORCING. HOWEVER...WITH SFC TEMPERATURES IN THE TEENS...SNOW/WATER
RATIOS OF 20:1 WILL ALLOW FOR THE POTENTIAL FOR 1 IN/HR RATES IN THE
MDT SNOWFALL.

..CROSBIE.. 01/02/2005

...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...CAR...GYX...BOX...BTV...ALY...BGM...BUF...

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