…Heavy mountain snow forecast for the Sierra Nevada late Saturday, and
then the Great Basin and northern Rockies into Sunday…
…Wintry mix including some ice continues for portions of the Upper
Midwest late Saturday, spreading into the central Appalachians Sunday…
A low pressure system centered over the Midwest states Saturday evening is
forecast to track across the Ohio Valley tonight and then across the
northern Mid-Atlantic and Northeast Sunday and into Sunday night, with
generally light rain for most areas affected. Some mixed precipitation,
including some light freezing rain, is also likely across portions of
Wisconsin and Michigan, and also the Central and northern Appalachians,
where some winter weather advisories are now in effect. More impactful
winter weather is expected for the higher terrain of eastern West Virginia
and into south-central PA, where winter storm warnings are in effect. The
anomalously strong surface high over the Northeast U.S. will provide some
cold air damming once this system arrives, with warmer air aloft
over-riding the colder air closer to the surface providing the environment
for mixed wintry precipitation.
Once that system departs, another area of moderate to locally heavy rain
is likely to develop Monday from the central Plains to the Ohio Valley in
conjunction with a cold front intercepting moist southerly flow from the
Gulf of Mexico. The occluded surface low well to the north near Lake
Superior should have enough moisture to provide mainly light snow across
portions of North Dakota and into northern Minnesota. Breezy to windy
conditions are likely to develop in the wake of this front across the
Upper Midwest and Great Lakes region into Monday night.
Multiple rounds of precipitation are expected to continue from the
northern half of California to Washington state as a couple of shortwaves
pass through the region, with the first moving inland this evening,
followed a second one Monday afternoon. Heavy snow is expected for the
Sierra Nevada with the first event, with 1-2 feet of accumulation likely
for the higher terrain. Moderate snow is then expected for the
Intermountain West mountain ranges and then the Northern Rockies as the
moisture associated with this moves inland. The next round likely arrives
during the overnight hours Sunday night, with rain near the coast and
moderate to heavy snow from the Cascades to the northern Sierra Nevada.
Hamrick
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php