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

Valid 12Z Sat Dec 04 2021 - 12Z Mon Dec 06 2021

...Winter storm to produce heavy snow and gusty winds from the Northern
Plains to the Upper Great Lakes this weekend...

...A strong cold front entering the Midwest and Southern Plains by Sunday
evening could spark isolated severe thunderstorms and instances of flash
flooding from the lower Ohio Valley to eastern Texas... 

Much of the active weather located across CONUS through the beginning of
next week will be associated with a strong area of low pressure forecast
to traverse the northern tier. Upper level energy combined with Pacific
moisture are currently entering the Northwest and will spread into the
northern High Plains this morning. As it does so, the Washington Cascades
and far northern Rockies are expected to pick up around 6 to 12 inches of
snow today, with locally higher amounts. By this evening and into early
Sunday, a developing area of low pressure over central Montana will move
eastward and spread moderate-to-heavy snowfall just to the south of the
U.S.-Canada border. This storm system is then forecast to continue
strengthening on Sunday as it enters the Upper Midwest and Great Lakes,
with gusty winds and bitterly cold air trailing closely behind. By Monday
morning, storm total snowfall amounts over 6 inches are expected to
stretch through northern North Dakota/Minnesota and into portions of far
northern Wisconsin and the U.P. of Michigan. The combination of heavy snow
and gusty winds will likely make travel treacherous at times for this
region. Winter Storm Watches and Warnings, as well as Winter Weather
Advisories have been issued.

The other facet of this early-December winter storm will be found along
and ahead of an attached cold front that is forecast to reach the Midwest
and Southern Plains by Sunday evening. Warm and well above average
temperatures out ahead of this cold front will clash with the approaching
arctic airmass and likely spark a line of showers and thunderstorms
extending from the Ohio Valley to eastern Texas. Isolated instances of
severe weather and flash flooding are possible into Monday morning for
this section of the country. Correspondingly, the Storm Prediction Center
has issued a Marginal Risk (level 1/5) of severe weather from far southern
Indiana to East Texas. A Marginal Risk (level 1/4) of excessive rainfall
has been issued between far southwest Ohio and central Arkansas.

Elsewhere, light snow showers and lake effect snow is likely throughout
the Interior Northeast and northern New England later today as a weak area
of low pressure swings into the region from Canada. For the Northwest,
another round of wintry weather is forecast to enter by Monday morning.
Air temperatures associated with this system could be cold enough to
support light snow in the lower elevations of Washington.  

Snell

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