Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
401 AM EST Fri Nov 22 2019

Valid 12Z Fri Nov 22 2019 - 12Z Mon Nov 25 2019


Days 1-3...

...Central Rockies/Plains...
An upper low centered near the Four Corners region Friday morning
is forecast to translate east into the central High Plains by the
afternoon.  Ongoing snow over the central Rockies is forecast to
gradually diminish during the morning and early afternoon, with a
few more inches possible across the central Colorado and far
northern New Mexico ranges.  Meanwhile, expect snows to develop
near the upper low center, with a few inches possible across
central Kansas during the morning into early afternoon hours.

...Ohio Valley to the Northeast...
Models show the upper low transitioning to an upper wave as it
moves from the mid Mississippi to the lower Ohio valley on
Saturday.  Expect mixed precipitation with minor snow/ice
accumulations northwest of a surface low lifting northeast into
the Ohio Valley on Saturday.  By Sunday morning, models show a
coastal wave developing and tracking northeast off the northern
Mid-Atlantic and New England coasts.  A wintry mix on the backside
of the system is expected to produce some light snow and ice
accumulations across portions of Upstate New York into central and
northern New England on Sunday.

...Pacific Northwest and Northern Rockies...
A pair of shortwave troughs embedded within strong northwest flow
are expected to bring organized precipitation and colder air back
into the northwestern U.S., with locally heavy snow possible
across the higher peaks of the northern Cascades and Rockies. 
Models show the initial wave diving southeast into the Northwest
Sunday morning, followed by a second wave bringing additional cold
air into the region Sunday night.  Mountain snows are expected
from the Olympics and northern Cascades to Wyoming, with several
inches likely along the higher peaks of the northern Cascades by
Monday morning.

The probability of significant icing (0.25 inch) is less than 10
percent.

Pereira