Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
243 AM EST Fri Nov 19 2021

Valid 12Z Fri Nov 19 2021 - 12Z Sun Nov 21 2021

...Cold Canadian Air-mass Arrives in the East Today, Warming Trend in the
Heartland on Saturday...

...Rain and Mountain Snow for the Northwest & Northern Rockies Through
Friday Night, Showers in the Ohio Valley Sunday Morning...

...Favorable Fire Weather Conditions in the Southern High Plains &
Southern California This Weekend...

An expansive area of Canadian high pressure in the Heartland is advancing
east this morning, ushering in some of the coldest temperatures of the
season to date east of the mighty Mississippi River. Even in the Southern
Plains it is quite cold with Freeze Warnings in place from the ArkLaTex to
the Upper Rio Grande regions. Friday's high temps from the Ohio Valley to
the Northeast will struggle to get out of the 40s today with blustery
conditions causing wind chills to be near or below freezing this morning.
The combination of windy conditions and very cold low level temperatures
funneling over the Great Lakes will lead to more lake effect snow showers
this morning. Winter Weather Advisories remain in place downwind of Lakes
Superior, northern Michigan, Erie, and Ontario with a couple more inches
of snowfall expected. Chilly temperatures stick around over the eastern
third of the U.S. on Saturday with the lone exception being South Florida
where warm and muggy conditions are firmly entrenched. After a couple days
of considerably cooler temperatures, warmer conditions arriving in the
Plains eventually reaches the East Coast by the end of the weekend thanks
to progressive zonal flow atop the Lower 48. The next injection of
abnormally cold temperatures arrives in the Midwest on Sunday as a potent
upper trough and an amplifying ridge over the West Coast direct yet
another Canadian air-mass into the North Central U.S. to close out the
weekend.

Precipitation-wise, a Pacific storm system is delivering valley rain
showers and mountain snow to the Northwest and northern Rockies today.
Winter Weather Advisories have been posted for parts of the interior
Northwest due to light, yet potentially disruptive snowfall accumulations
this morning. The heaviest snowfall accumulations are likely to occur in
the Tetons where over a foot of snow is possible. Farther east, an
approaching cold front and a weak upper level disturbance aloft will help
to ignite showers and thunderstorms over South Florida today and Saturday.
Some thunderstorms could be severe and/or produce excessive rainfall
rates. By Sunday morning, a frontal boundary sweeping across the Midwest
and entering the Great Lakes may generate scattered showers over the Ohio
Valley and Great Lakes. A little farther east, a wintry mix could develop
over the northern Mid-Atlantic Sunday morning as approaching light
precipitation overruns sub-freezing temperatures near the surface.

In addition, a warm up coinciding with dry conditions and gusty winds is a
recipe for favorable fire weather conditions in parts of the southern High
Plains today and Saturday. The Storm Prediction Center has issued an
Elevated Risk in their Fire Weather Outlook for portions of the Texas and
Oklahoma Panhandles, far southwest Kansas, and eastern New Mexico.
Elsewhere, strengthening high pressure over the Intermountain West
Saturday night will lay the groundwork for Santa Ana winds to ensue over
Southern California into Sunday morning. Residents in Southern California
can expect strong wind gusts and favorable fire weather conditions
Saturday night into Sunday morning.

Mullinax


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