MESO: Mesoscale Discussion 0224

ACUS11 KWNS 101454
SWOMCD
SPC MCD 101453
MNZ000-WIZ000-SDZ000-NDZ000-101900-

MESOSCALE DISCUSSION 0224
NWS STORM PREDICTION CENTER NORMAN OK
0953 AM CDT TUE MAR 10 2009

AREAS AFFECTED...MUCH OF NRN/CENTRAL MN AND PARTS OF SERN ND AND
NERN SD

CONCERNING...HEAVY SNOW

VALID 101453Z - 101900Z

RAPID INCREASE IN AREAL COVERAGE OF SNOW SERN ND/NERN SD INTO WRN MN
AHEAD OF VIGOROUS S/WV TROUGH AND STRONG MID/UPPER JET MAX MOVING
FROM CENTRAL PLAINS TO UPPER MS VALLEY BY THIS EVENING. SURFACE LOW
SRN IA WILL DEEPEN NEWD INTO SRN WI BY LATER THIS AFTERNOON WITH
VERY COLD AIR SPREADING EWD ACROSS DAKOTAS INTO WRN /NRN MN.
COMBINATION OF LOW/MID LEVEL WARM ADVECTION AND INCREASE IN PW TO
GREATER THAN .5 INCHES ALONG WITH WEAK INSTABILITY ABOVE 600MB
SUPPORTS THE CONVECTIVE MODE NOTED ON THE RADAR/VISIBLE SATL IMAGERY
SWRN MN.

SNOW RATES ALREADY 1 IN/HR HAVE DEVELOPED SERN ND/NERN SD AND THESE
CONDITIONS WILL SPREAD/DEVELOP RAPIDLY E/NEWD ACROSS MUCH OF
NRN/CNTRL MN THRU 21Z. WITH SNOW RATIOS OF 15-20 TO 1 GIVEN THE COLD
AIR MASS SPREADING EWD...SNOW RATES UP TO 2 IN/HR
LIKELY...PARTICULARLY WITH THE CONVECTIVE ENHANCEMENT. AS SURFACE
LOW DEEPENS...MODELS RAPIDLY TIGHTEN THE PRESSURE GRADIENT ON THE
COLD SIDE OF THE LOW TRACK ACROSS NRN INTO WRN MN WITH NEAR BLIZZARD
CONDITIONS DEVELOPING DURING THE AFTERNOON GIVEN THE SNOW RATES.

..HALES.. 03/10/2009

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

ATTN...WFO...DLH...MPX...FGF...ABR...

LAT...LON 44869637 45499733 46509773 47139714 47549655 48119586
48879471 48619358 48049171 47029171 46669223 45209505
44869637

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