MESO: Mesoscale Discussion 2170

ACUS11 KWNS 312306
SWOMCD
SPC MCD 312305
MNZ000-SDZ000-NDZ000-010300-

MESOSCALE DISCUSSION 2170
NWS STORM PREDICTION CENTER NORMAN OK
0505 PM CST FRI DEC 31 2010

AREAS AFFECTED...NERN SD/ERN ND/NWRN MN

CONCERNING...BLIZZARD

VALID 312305Z - 010300Z

A HEAVY SNOW BAND ACROSS NERN SD...SERN ND...AND W CNTRL MN WILL
GRADUALLY LIFT NWD TONIGHT INTO ERN ND AND NWRN MN. STRONG WINDS
WILL CONTINUE THROUGH MUCH OF THE NIGHT...LEADING TO BLIZZARD
CONDITIONS EVEN AS SNOWFALL RATES EVENTUALLY DECREASE FROM S TO N.

A STRONG UPPER LOW OBSERVED ON WV IMAGERY OVER CNTRL NEB AS OF 23Z
IS GRADUALLY PROGRESSING NEWD...WITH THE LEADING EDGE OF ASCENT AND
FAVORABLE UPPER DIVERGENCE OVER THE ERN DAKOTAS/SRN AND CNTRL MN. A
BAND OF HEAVY SNOW ORIENTED ROUGHLY E TO W OVER CNTRL MN INTO THE
ERN SD/ND BORDER IS ONGOING AS STRONG WARM ADVECTION PRIMARILY ABOVE
850 MB /WITH MINNEAPOLIS VAD SHOWING A 60 KT LOW LEVEL
JET/...CONTRIBUTES TO STRONG VERTICAL MOTION AND SATURATION OF
LOW/MID LEVELS. THE EXTREMELY COLD ARCTIC AIR MASS AT THE SURFACE IN
COMBINATION WITH STRONG WARM ADVECTION ABOVE THE SURFACE SHOULD LEAD
TO HIGH SNOWFALL RATIOS...AND RAPID ACCUMULATIONS. SURFACE PRESSURE
FALLS /1 TO NEAR 2 MB AN HOUR/ ARE GREATEST NEAR THE ND/MN
BORDER...AND SUGGEST THE TRACK OF THE SURFACE LOW CURRENTLY OVER
SWRN MN MAY BE SLIGHTLY TO THE W OF THE MOST RECENT 21Z MODEL
FORECASTS...WHICH GENERALLY SHOW THE LOW DEVELOPING NWD INTO E CNTRL
MN. AS A RESULT...HEAVY SNOWFALL MAY ALSO BE SLIGHTLY TO THE W OF
21Z FORECASTS. EXPECT RATES TO RAPIDLY INCREASE INTO ERN ND AND W
CNTRL/NWRN MN TONIGHT...WHILE GRADUALLY DIMINISHING OVER SRN
PORTIONS OF THE MD AREA. CURRENT SURFACE OBSERVATIONS SHOW
OCCASIONAL GUSTS TO 45 MPH. A STRONG PRESSURE GRADIENT INTO THE
NIGHT WILL LIKELY MAINTAIN BLIZZARD CONDITIONS AS GUSTS NEAR 35 TO
45 MPH CONTINUE.

..HURLBUT.. 12/31/2010

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

ATTN...WFO...FGF...ABR...BIS...

LAT...LON 45899672 45349811 45849938 46749962 47519959 47869855
47999743 47949682 47869571 47249472 46949466 46449512
46219615 45899672

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