SPC MESOSCALE DISCUSSION 2287 FOR ERN SD / SWRN AND WCNTRL MN
CONCERNING...HEAVY SNOW AND NEAR BLIZZARD CONDITIONS...

VALID 261645Z - 262100Z

A PROLONGED PERIOD OF SNOWFALL RATES AT 1-2 INCHES PER HOUR ARE
EXPECTED TO BE CONCENTRATED OVER ERN SD INTO SWRN/WCNTRL MN THROUGH
THIS AFTERNOON.  

15Z SURFACE ANALYSIS PLACES THE SURFACE LOW OVER EXTREME SCNTRL NEB
WITH PERSISTENT PRESSURE FALLS OVER WRN IA DURING THE LAST SEVERAL
HOURS.  OBJECTIVE ANALYSES/12Z ETA/RUC MODELS SUGGEST THE SURFACE
LOW WILL TRACK TOWARD SWRN IA BY 27/00Z...AS THE UPPER LOW LIFTS
SLOWLY NEWD.  12Z UPPER AIR ANALYSIS SHOWS A STRONG 850 MB THERMAL
GRADIENT OVER ERN SD INTO CENTRAL MN.  MODELS INDICATE PERSISTENT
FRONTOGENETICAL FORCING OVER SERN/ERN SD INTO SWRN/WCNTRL MN
THROUGH AT LEAST 00Z...SUPPORTING HEAVY SNOWFALL RATES.  A TIGHT
SURFACE PRESSURE GRADIENT WITH THE SURFACE LOW WILL RESULT IN
BLOWING SNOW WITH NEAR-BLIZZARD CONDITIONS FROM ERN SD INTO EXTREME
WRN MN WHERE SUSTAINED NNELY WINDS AT 20-30 KT WILL REDUCE
VISIBILITIES TO LESS THAN 1/4 MILE. 

..PETERS.. 11/26/01