Quantitative Precipitation Forecast Discussion
NWS Weather Prediction Center College Park MD
230 PM EDT Fri Mar 30 2018


Prelim Day 1 QPF Discussion
Valid Mar 31/0000 UTC thru Apr 01/0000 UTC
Reference AWIPS Graphics under...Precip Accum - 24hr


Day 1

...Northern Plains into the Upper MS Valley and Upper Great
Lakes...

An area of low pressure will move across the Northern Plains and
into the Upper MS Valley tonight into Saturday. Will see strong
isentropic lift ahead of this low...with an axis of strong
frontogenesis and steeper lapse rates north of the low likely
supporting a band of heavy snow. Some disagreement exists with the
exact corridor of these higher QPF amounts. In general have noted
a southward trend over the past few model cycles. WPC thus trended
in this direction as well...although still some uncertainty on
where the heaviest banding sets up. The 12z GFS and GEM Regional
are the furthest south solutions, with the 12z HRW ARW and 0z
ECMWF furthest north. Overall went for a consensus between these
two solutions...weighted a bit more towards the further south
GFS/GEM Regional given trends. Looks like a nice swath of
0.5"+...and while not in our deterministic forecast given model
spread...would anticipate some 0.75"+ amounts to occur where
banding ends up maximized...likely somewhere from east central MN
into north central WI.

...Northern Rockies...

In the wake of the area of low pressure moving eastward from the
Northern Plains into the Upper MS Valley---the arctic front will
push southward Friday and become banked up against the Northern
Rockies.  Post frontal upslope flow will support continued snows
into portions of the Northern Rockies.

Chenard