[MCD] SWOMCD

Sat Dec 3 18:27:49 UTC 2005

ACUS11 KWNS 031825
SWOMCD
SPC MCD 031825 
INZ000-ILZ000-WIZ000-IAZ000-MOZ000-NEZ000-KSZ000-040030-

MESOSCALE DISCUSSION 2516
NWS STORM PREDICTION CENTER NORMAN OK
1225 PM CST SAT DEC 03 2005

AREAS AFFECTED...EXTREME NRN KS/SERN NEB/IA/SRN WI/NRN IL

CONCERNING...HEAVY SNOW 

VALID 031825Z - 040030Z

...MODERATE TO HEAVY SNOW IS EXPECTED THIS AFTN ACROSS MAINLY SERN
NEB/IA WITH SNOW INCREASING ACROSS SRN WI/NRN IL. HOURLY RATES WILL
RANGE FROM 1 TO 2 INCHES...

SEVERAL FACTORS WILL CONTRIBUTE TO BANDS OF MODERATE TO HEAVY SNOW
THIS AFTN. ON THE SYNOPTIC SCALE...A SHORTWAVE TROUGH IS NOW LIFTING
NEWD FROM KS/NEB...AND THIS PLACES THE ENTIRE AREA WITHIN A ZONE OF
LARGE SCALE SLOPED ASCENT. SOME JET COUPLING IS ALSO LIKELY
OCCURRING AS 12Z UPPER AIR ANALYSIS DEPICTS JET STREAK ACROSS SRN
KS/MO AND ANOTHER DEPARTING JET MAX FROM IND INTO THE MID ATLANTIC. 

A BAND OF MODERATE TO HEAVY SNOW HAS BEEN ONGOING FOR THE LAST
SEVERAL HOURS ACROSS SERN NEB INTO IA PER LOCAL RADAR IMAGERY...WITH
MODERATE/HEAVY SNOW NOW EXTENDING FROM NEAR HARLAM IA TO JUST NORTH
OF DSM...FROM AMES TO MARSHALLTOWN. FAVORABLE MID LEVEL
FRONTOGENETICAL FORCING WILL ENCOURAGE NARROW BUT HEAVY MESOSCALE
BANDS OF SNOW. THERMODYNAMIC PROFILES LOOK VERY SUPPORTIVE OF HEAVY
SNOW...WITH FORECAST SOUNDINGS SUGGESTING DEEP LIFT THROUGHOUT THE
DENDRITIC LAYER EXTENDING FROM 700-500MB. 

LATEST NAM GUIDANCE SUGGESTS HEAVIEST SNOWS WILL SET UP FROM ERN IA
ALONG THE WI/IL BORDER BETWEEN 21Z-00Z. EXPERIMENTAL SHORT RANGE
ENSEMBLE SOLN SUPPORTS THIS WITH MEAN 1 INCH PER HOUR RATES
CONTINUING ACROSS MUCH OF CNTRL/ERN IA THIS AFTN BEFORE SPREADING TO
NEAR MKE/ORD BY 04/00Z.

..TAYLOR.. 12/03/2005

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

ATTN...WFO...LOT...MKX...DVN...ARX...DMX...EAX...OAX...TOP...GID...

41638865 39489733 40099833 41979563 43229242 43478986
43338758 41688715 

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