Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 AM EST Sat Nov 20 2021

Valid 12Z Sat Nov 20 2021 - 12Z Mon Nov 22 2021

...Chilly conditions envelope the East today with more seasonal temps
returning by Sunday...

...Heavy showers and thunderstorms possible in South Florida; accumulating
mountain snow in the Rockies today...

...Lake effect snowfall for Upper Great Lakes & rain from the Northeast to
the Deep South Sunday night...

The weekend forecast kicks off with a fairly tranquil Saturday throughout
much of the Lower 48. An expansive dome of high pressure along the East
Coast is responsible for chilly temperatures and mostly dry conditions.
Freeze Warnings and Frost Advisories have been issued for parts of the
Southeast this morning for areas witnessing their first frosts and freezes
of the season. Meanwhile, another pair of high pressure systems in the
North-Central and Northwest U.S. will help to keep these regions dry
throughout the weekend. Saturday's most active weather is set to occur
near a frontal boundary draped over central Florida. Scattered showers and
thunderstorms are likely in South Florida with locally heavy rainfall
rates possible. Farther west, a weak area of low pressure associated with
a passing upper level disturbance will generate mountain snowfall in the
Central Rockies. Lastly, Elevated fire weather conditions are in place for
portions of the southern High Plains and Southern California today.

By Sunday, a pair of upper level features are set to track through the
Midwest and Ohio Valley. The most vigorous upper level trough set to pass
through the Great Lakes on Sunday will cause a wave of low pressure to
strengthen over southeast Canada. A potent cold front then delivers a shot
of considerably colder temperatures across the Midwest and Great Lakes
late Sunday into Monday, causing heavy lake effect snow showers to
breakout downwind of the Great Lakes on Monday. Ahead of the storm
system's cold front, numerous showers are forecast to breakout from the
Deep South to the northern Mid-Atlantic Sunday afternoon. Expect these
showers to reach the Northeast and extend as far south as the Southeast
Sunday night. In addition, lingering showers and thunderstorms are
forecast to stick around over South Florida once again on Sunday. Out
west, an intensifying ridge of high pressure means a quiet day
weather-wise throughout much of the region. However, brisk offshore winds
over Southern California mean Santa Ana winds increase the odds for
critical fire weather conditions. As a result, Red Flag Warnings and a
Critical Risk for fire weather conditions have been issued near the
Southern California coast.

Mullinax

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