Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
330 PM EST Sun Dec 05 2021

Valid 00Z Mon Dec 06 2021 - 00Z Wed Dec 08 2021

...Heavy snow and high winds across the Upper Great Lakes 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 through Monday morning...

...Temperatures will be 10 to 20 degrees above average over parts of the
East Coast...

A strong storm over the Upper Midwest will move northeastward into Canada
by Monday evening, while the associated front moves off the East Coast
overnight Monday. The system will produce heavy snow over parts of the
Upper Great Lakes through Monday evening. As a result, High Wind Warnings,
Winter Storm Advisories, and Winter Storm Warnings are up along the
Northern Tier through Sunday night. Rain over the Northeast into the
Central Appalachians will change over to snow Monday afternoon into the
evening.  The light snow will move off the Northeast Coast by Tuesday
afternoon. 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.  In the wake of the storm, lake effect snow
will develop downwind from the Great Lakes.

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 through 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
through 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 10 to 20 degrees above average over
parts of the East Coast on Monday.  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. Overnight Monday, rain will expand into parts of
California that will move southward to Southern California by Tuesday
evening and into parts of the Southwest overnight Tuesday into Wednesday
morning.

Ziegenfelder

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