Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
352 AM EDT Mon Oct 18 2021

Valid 12Z Mon Oct 18 2021 - 12Z Wed Oct 20 2021

...Upper level low to generate accumulating mountain snowfall from the
Sierra Nevada to the Intermountain West...

...Below normal temperatures to persist in the West; seasonally cool
temperatures along the East and Gulf Coasts to moderate by mid-week;
warmest temperatures versus normal in the Midwest & Great Lakes...

As a large dome of high pressure keeps a tranquil weather pattern in place
across much of the South and East, the western half of the Lower 48 will
feature the most active weather to kickoff the work-week. An area of low
pressure associated with a potent upper level low is forecast to track
from the northern Great Basin this morning into the heart of the
Intermountain West later today. Accumulating snowfall in the northern
Sierra Nevada will conclude by this afternoon with several more inches of
snow possible. The storm system will march east into the Rockies by
Tuesday and eventually reach the Great Plains Tuesday night. Lower
elevations can expect rain showers while mountains such as the Uinta, Wind
River, Big Horn, and Laramie ranges could pick up anywhere from 1 to 2
feet of snow between today and Wednesday morning. Much of central Wyoming
is under a Winter Storm Watch in advance of the impending winter storm.
There is no rest in the weather pattern out West as yet another storm
system approaching from the northeast Pacific ushers in more
coastal/valley rain and mountain snow to the Pacific Northwest Tuesday
night into Wednesday.

Temperatures the first half of the week will be coolest versus normal over
the western third of the CONUS. Daily temperature departures ranging
between 10 to 15 degrees below normal are anticipated today for much of
California and Nevada. As the upper trough responsible for the wintry
weather in the Rockies moves east on Tuesday, temps will cool to below
normal levels as it works in tandem with another cold front pushing south
through the Northern Plains. Meanwhile, seasonally cool temperatures will
stick around in the Deep South and along the East Coast today. Conditions
are cold enough that some parts of western Tennessee and the southern
Appalachians have been placed under Frost Advisories. Look for
temperatures to gradually warm up along the Gulf and East Coasts,
eventually returning to above normal levels by mid-week. Lastly, the
regions witnessing the warmest temperatures versus normal will be the
Midwest and Great Lakes. Daytime highs will soar into the 70s with some
locations potentially reaching as high as 80 degrees.

Mullinax

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