[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 160046
SWOMCD
SPC MCD 160045 
WIZ000-160645-

MESOSCALE DISCUSSION 0143
NWS STORM PREDICTION CENTER NORMAN OK
0645 PM CST WED FEB 15 2006

AREAS AFFECTED...SRN WI

CONCERNING...HEAVY SNOW 

VALID 160045Z - 160645Z

A PERIOD OF HEAVY SNOW WITH RATES EXCEEDING 1 INCH PER HOUR IS
EXPECTED TO DEVELOP BETWEEN 03 UTC AND 06 UTC.

VERY STRONG WARM ADVECTION/ISENTROPIC ASCENT WILL LEAD TO THE
DEVELOPMENT OF LOCALLY HEAVY SNOW LATER THIS EVENING. SNOWFALL RATES
ARE EXPECTED TO EXCEED 1 INCH PER HOUR IN EMBEDDED BANDS/CONVECTIVE
ELEMENTS ORIENTED EAST-TO-WEST IN THE VICINITY OF STRONG LOW/MID
TROPOSPHERIC FRONTOGENETICAL FORCING. THIS FORCING IS WELL DEPICTED
BY THE 18 UTC NAM IN THE 800 TO 700 MB LAYER...WITH WEAK UPRIGHT
CONDITIONAL INSTABILITY /MUCAPE ABOUT 50 J/KG/ REACHING AS FAR NORTH
AS NRN IL BY 03 UTC. FARTHER NORTH...NAM SHOWED SLANTWISE
INSTABILITY POTENTIAL FROM NRN IL THROUGH SRN WI.

LARGE SCALE ASCENT SUPPORTS THE DEVELOPMENT OF LIGHT SNOW OVER MUCH
OF SRN WI THIS EVENING...WITH FRONTOGENETICAL CIRCULATION AND
SLANTWISE INSTABILITY PRODUCING BANDS OF EMBEDDED HEAVY SNOW WITH
RATES OF 1 INCH PER HOUR. FORCING FOR HEAVY SNOW SHIFTS RAPIDLY NEWD
AFTER 06 UTC.

00 UTC SURFACE TEMPERATURES WERE ALREADY AT OR BELOW 32F WITH
DEWPOINTS IN THE TEENS AND LOWER 20S. WET BULB COOLING LEAVES LITTLE
DOUBT THAT PRECIPITATION TYPE WILL OCCUR AS SNOW.

..BRIGHT.. 02/16/2006

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

ATTN...WFO...MKX...ARX...

43658978 43858872 43448772 42768823 42708984 43009029 

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