[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 220557
SWOMCD
SPC MCD 220556 
PAZ000-WVZ000-OHZ000-KYZ000-MIZ000-INZ000-ILZ000-WIZ000-IAZ000-221200-

MESOSCALE DISCUSSION 0115
NWS STORM PREDICTION CENTER NORMAN OK
1156 PM CST FRI JAN 21 2005

AREAS AFFECTED...SRN GREAT LAKES/MIDDLE AND UPPER OH VALLEY

CONCERNING...HEAVY SNOW 

VALID 220556Z - 221200Z

POTENTIAL FOR HOURLY SNOW RATES APPROACHING 1-1.5 INCHES/HOUR ARE
EXPECTED TO DEVELOP EWD ACROSS PORTIONS OF SRN LOWER MI AND NRN
IND/OH. ADDITIONALLY...POCKETS OF FREEZING RAIN WITH HOURLY RATES
APPROACHING .05-.10 INCH WILL BECOME INCREASINGLY LIKELY TOWARD 12Z
OVER SRN OH INTO WRN WV.

00Z UPPER-AIR ANALYSIS AND CURRENT WATER VAPOR IMAGERY INDICATE
DEEPENING MID/UPPER-LEVEL TROUGH FROM THE NRN PLAINS INTO UPPER
MIDWEST WITH EMBEDDED LEAD VORTICITY MAXIMUM OVER THE LOWER MO
VALLEY. LATEST MODEL GUIDANCE IS CONSISTENT TAKING THIS LEAD FEATURE
EWD ACROSS THE OH VALLEY OVERNIGHT WHILE STRONGER...UPSTREAM SYSTEM
DIGS SEWD ACROSS THE UPPER MS VALLEY. IN THE LOW-LEVELS...PRIMARY
SURFACE LOW IS EXPECTED TO DEVELOP EWD ALONG/JUST N OF THE OH RIVER
IN ASSOCIATION WITH LEAD DISTURBANCE.

LATEST RADAR MOSAIC/IR SATELLITE IMAGERY SHOW A WELL DEVELOPED
CLOUD/PRECIPITATION SHIELD DOWNSTREAM FROM LEAD SHORTWAVE TROUGH
FROM SRN WI/NRN IL INTO SRN LOWER MI...NRN IND AND NWRN OH. LOCAL
SURFACE OBSERVATIONS INDICATE HEAVIEST SNOWFALL CURRENTLY FROM JVL
SEWD THROUGH THE CHICAGO METRO AREA TO NEAR SBN WHERE VISIBILITIES
OF 1/4 TO 1/2 MILE ARE COMMON. 3-4 MB/2 HR PRESSURE FALLS ACROSS
THIS SAME AREA /PER CURRENT MESOANALYSIS/ SUGGESTS THE PRESENCE OF
STRONG...DEEP-LAYER VERTICAL MOTION OWING TO COUPLING OF LOW-LEVEL
WAA AND MID/UPPER-LEVEL DCVA.

EXPECT AXIS OF HEAVIEST SNOWFALL TO SHIFT EWD OVERNIGHT ACROSS SRN
LOWER MI AND NRN PORTIONS OF IND/OH. HERE...PERSISTENT... DEEP-LAYER
ASCENT WILL SUPPORT HOURLY SNOW ACCUMULATIONS APPROACHING 1-1.5
INCHES. FORECAST SOUNDINGS AND PLAN VIEW PRECIPITATION TYPE
FORECASTS SUGGEST THAT STRONG LOW-LEVEL WAA ALONG SWLY 45-55 KT LLJ
AXIS MAY SUFFICIENTLY WARM 1-2 KM AGL LAYER TO SUPPORT POCKETS OF
FREEZING RAIN TOWARD 12Z OVER PORTIONS OF SERN OH INTO WRN WV.

FARTHER W...SNOW RATES WILL DIMINISH OVER SRN WI/NRN IL BY 08-09Z 
AS STRONGEST FORCING ASSOCIATED WITH LEAD SHORTWAVE TROUGH SHIFTS
EWD.

..MEAD.. 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...PBZ...RLX...CLE...ILN...DTX...LMK...IWX...GRR...IND...GRB...LOT...ILX...MKX...DVN...ARX...

43928889 43348683 42208245 41648047 39758016 38758092
38398205 38728501 39208676 41739049 43469050 

WWWW