[MCD] SWOMCD

Thu Dec 8 18:04:07 UTC 2005

ACUS11 KWNS 081800
SWOMCD
SPC MCD 081800 
WVZ000-OHZ000-KYZ000-INZ000-ILZ000-090000-

MESOSCALE DISCUSSION 2546
NWS STORM PREDICTION CENTER NORMAN OK
1200 PM CST THU DEC 08 2005

AREAS AFFECTED...OH VALLEY

CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 

VALID 081800Z - 090000Z

A NARROW ZONE OF FREEZING RAIN...WITH RATES RANGING FROM .05-0.1
INCH PER HOUR...IS EXPECTED TO SPREAD NEWD ALONG THE OH RIVER VALLEY
INTO SRN OH THIS AFTERNOON.  THE HIGHEST RATES SHOULD BE 20-25 MILES
EITHER SIDE OF A LINE FROM 30 E OWB TO 20 S LUK TO 30 ESE ZZV. 
SLEET MAY ALSO MIX IN WITH THE FREEZING RAIN AT TIMES...ESPECIALLY
ALONG THE NRN PERIPHERY OF THIS REGION...AS PRECIPITATION
TRANSITIONS TO SNOW.  THIS MIXED PRECIPITATION SHOULD CHANGE TO
MAINLY SNOW BY 21-23Z WEST OF A LINE FROM CMH TO CENTRAL KY.

MEANWHILE...ALL SNOW IS EXPECTED NORTH OF THE ZONE OF FREEZING RAIN.
SNOWFALL RATES WILL LIKELY INCREASE THROUGH THE AFTERNOON WITH RATES
UP TO...AND AT TIMES...EXCEEDING 1 INCH PER HOUR.  

LARGE SCALE ASCENT WILL CONTINUE TO INCREASE THIS AFTERNOON ACROSS
THE OH VALLEY AHEAD OF THE MID LEVEL SHORT WAVE TROUGH WHICH IS
MOVING EWD TOWARD WRN IL THIS AFTERNOON.  IN RESPONSE TO STRONG
HEIGHT FALLS WITH THIS STORM SYSTEM...A SLY LLJ WILL STRENGTHEN TO
60-70 KT ACROSS THE TN VALLEY NOSING INTO NRN KY/SRN OH BY MID-LATE
AFTERNOON.  THE STRONG UVVS EXPECTED ACROSS IND/NRN KY INTO OH WILL
AID IN SATURATING THE INITIALLY DRIER AIR MASS LOCATED BELOW 3 KM AS
OBSERVED IN SWRN OH PER 12Z ILN SOUNDING.  MOISTURE ADVECTION ALONG
THE SLY LLJ WILL AID IN ADDITIONAL MOISTENING OF THE OH VALLEY AIR
MASS.

WAA ALONG THE NOSE OF THE LLJ IS EXPECTED TO SUPPORT A WARM LAYER
BETWEEN 1-2 KM AGL SUFFICIENT FOR A NARROW BAND OF FREEZING RAIN AND
AT TIMES MIXED WITH SLEET...GENERALLY ALONG THE IND/KY BORDER INTO
FAR SWRN OH AND MUCH OF SOUTH CENTRAL TO SERN OH THIS AFTERNOON. 
SOUTH OF THIS ZONE OF FREEZING PRECIPITATION...SURFACE TEMPERATURES
WILL CONTINUE TO RISE ABOVE 32 F...ALLOWING FOR A TRANSITION TO
RAIN.  AS THE SURFACE LOW...NOW LOCATED OVER NERN MS/WRN TN...TRACKS
INTO ERN KY BY 09/00Z...COOLING IN THE 1-2 KM AGL LAYER GENERALLY
WEST OF A LINE FROM CMH TO CENTRAL KY WILL SUPPORT THERMODYNAMIC
PROFILES FOR ALL SNOW BY 21-23Z.

..PETERS.. 12/08/2005

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

ATTN...WFO...PBZ...RLX...CLE...JKL...ILN...LMK...IWX...IND...PAH...LOT...ILX...

38048680 38768850 40018833 40758684 41088542 41248441
40838286 40478171 40048124 39108125 38338179 37388335
37188454 37108603 

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