Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
315 PM EST Sat Dec 04 2021

Valid 00Z Sun Dec 05 2021 - 00Z Tue Dec 07 2021

...Heavy snow and high winds across the Upper Midwest on Sunday into
Monday...

...There is a Marginal Risk of excessive rainfall and a Slight Risk of
severe thunderstorms over parts of the Lower Mississippi, Southern Ohio,
and Tennessee Valleys on Sunday into Monday morning...

...Temperatures will be 15 to 25 degrees above average over parts of the
Central/Southern Plains into the adjacent Middle/Lower Mississippi
Valley...

A rapidly deepening storm over the Northern High Plains will move eastward
to the Upper Great Lakes by Monday and into Canada by Monday evening. The
system will produce snow over parts of the Northern Rockies into the
Northern Plains that will steadily spread eastward across the Northern
Tier States into the Upper Great Lakes by Sunday afternoon. As a result,
High Wind Watches, Winter Storm Advisories, and Winter Storm Warnings are
up along the Northern Tier through Sunday. These warnings will likely
expand eastward over the Great Lakes on Sunday into Monday. The storm will
produce heavy snow and strong wind from the Northern Plains into the Upper
Great Lakes through Sunday night.  The snow and wind will result in
reduced visibilities and hazardous driving conditions. This will also be
the first widespread heavy snowfall of the winter season.

Meanwhile, moisture from the Western Gulf of Mexico will start to pool
along the associated front producing rain over parts of the Great Lakes,
Ohio, Middle/Lower Mississippi, and Tennessee Valleys by Sunday evening. 
Overnight Sunday, showers and thunderstorms will develop along and ahead
of the front over the Lower Mississippi and Tennessee Valleys; some of
these thunderstorms will be severe. Therefore, the SPC has issued a Slight
Risk of severe thunderstorms over parts of the Lower Mississippi and
Tennessee Valleys for Sunday into Monday morning.  The hazards associated
with these thunderstorms are frequent lightning, severe thunderstorm wind
gusts, hail, and a few tornadoes. Moreover, heavy rain will develop with
the showers and thunderstorms. Therefore, the WPC has issued a Marginal
Risk of excessive rainfall over parts of the Lower Mississippi, Southern
Ohio, and Tennessee Valleys on Sunday into Monday morning.  The associated
heavy rain will create localized areas of flash flooding, affecting areas
that experience rapid runoff with heavy rain. 

Furthermore, temperatures will be 15 to 25 degrees above average over
parts of the Central/Southern Plains into the adjacent Middle/Lower
Mississippi Valley on Sunday. Elsewhere, onshore flow will aid in
producing rain and higher elevation snow over the Pacific Northwest
through Sunday morning.  Overnight Sunday, upper-level energy and onshore
flow will produce a new round of rain and snow over the Northwest that
will expand inland over parts of the Great Basin and the Northern Rockies.
Furthermore, Monday, the snow levels will be low over parts of the
Northwest.

Ziegenfelder

Graphics are available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php