Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
342 AM EDT Fri Oct 11 2019

Valid 12Z Fri Oct 11 2019 - 12Z Mon Oct 14 2019

Days 1-3...

...Major early season snowstorm continuing in the Northern
Plains...

...Northern Plains to upper MS Valley...

A powerful, early-season winter storm will continue, with heavy
snow drifting eastward across North Dakota and northeast SD and
into adjacent western MN today and tonight. 
Strong low to mid-level frontogenesis in eastern North Dakota will
support banded precipitation and the formation of a well-defined
deformation zone...both of which will result in enhanced snowfall
rates.  Snowfall in the Dakotas is expected to linger into
Saturday as the system becomes occluded...resulting in heavy,
potentially historic accumulations for eastern North Dakota for
early October.  Probabilities of exceeding 2 feet are now over 50%
across portions of eastern ND.

The 00Z suite of guidance remained in good agreement with the
large-scale features.  The primary uncertainty is expected to be
the narrow band of mixed precipitation in western MN on day 1,
moving east towards Lake Superior on Day 2/Sat.

By Saturday, the mid/upper level circulation center continues to
drift out of the Dakotas and across northwest Minnesota to the
Canadian border. This will allow for snows to gradually taper off
across the Dakotas as drier air works in from the west. A period
of lake enhanced snow is possible in the arrowhead of MN.  This
tapers as low pressure departs into Canada on Sun.

The probability of significant icing is less than 10 percent Days
1-3.
The probability of heavy snow on Day 3 is less than 10 percent.

Petersen