000 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