[MCD] SWOMCD

Thu Nov 23 08:10:19 UTC 2006

ACUS11 KWNS 230812
SWOMCD
SPC MCD 230812 
MAZ000-NHZ000-VTZ000-NYZ000-PAZ000-231215-

MESOSCALE DISCUSSION 2230
NWS STORM PREDICTION CENTER NORMAN OK
0212 AM CST THU NOV 23 2006

AREAS AFFECTED...NERN PA...SERN NY...WRN MA

CONCERNING...FREEZING RAIN 

VALID 230812Z - 231215Z

AREAS OF LIGHT FREEZING RAIN MAY IMPACT PARTS OF NERN PA...THE MID
HUDSON VALLEY...AND NWRN MA THROUGH EARLY TODAY. GENERALLY LIGHT
FREEZING PRECIPITATION AMOUNTS OF AROUND 0.01 INCH PER HOUR ARE
EXPECTED TO DEVELOP OVER THESE AREAS BETWEEN 09Z AND 12Z.

SURFACE WET-BULB 0C ISOTHERM HAS REMAINED ESSENTIALLY STATIONARY
ALONG A AVP-POU-BDL LINE THIS MORNING AS LIFT AND MOISTENING
TRANSLATE STEADILY NEWD ON THE NOSE OF 40-50KT ELY LLJ. FORECAST
SOUNDINGS ACROSS THE REGION SUGGEST THAT THIS PROCESS WILL CONTINUE
TO ERODE EXTREMELY DRY SUB-CLOUD AIR MASS WITH EVAPORATIONAL COOLING
RESULTING IN THE DEVELOPMENT...OR MAINTENANCE...OF POCKETS OF NEAR
FREEZING TEMPERATURES AT THE SURFACE AS PRECIPITATION MOVES NWD.

AS DRY LAYERS UNDERGO MOISTENING AND WET-BULB COOLING...A FEW
FORECAST SOUNDINGS AND SOME PRECIPITATION-TYPE SCHEMES SUGGEST A LOW
PROBABILITY OF LIGHT SNOW REACHING THE SURFACE BEFORE A CHANGEOVER
TO LIGHT RA/FZRA. LATEST SREF MEAN GUIDANCE INDICATES A 30-40%
PROBABILITY OF FREEZING RAIN RATES AOA 0.05 INCH PER 3 HOURS FROM
NERN PA...ACROSS THE SRN CATSKILLS...AND OVER THE MID HUDSON VALLEY
TO WRN MA...THROUGH 12Z. THIS FORECAST APPEARS VERY REASONABLE BASED
ON LATEST RADAR AND BOUNDARY LAYER TEMPERATURE TRENDS.

..CARBIN.. 11/23/2006

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

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

42777252 42697206 42277261 42137327 41707429 41237527
41377585 41797569 42337478 42697395 42757333 