Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Sun Mar 19 2023

Valid 12Z Sun Mar 19 2023 - 12Z Tue Mar 21 2023

...Rain and heavy mountain snow arriving over California today will expand
into much of the western U.S. through Monday as snow develops over the
northern High Plains by early Tuesday...

...Cold high pressure system will keep much of the East & South chilly
through Monday with lingering lake effect snow showers today...

...Scattered showers and a few thunderstorms across South Florida as snow
ends early this morning across the Big Bend area of Texas...

A cold cyclonic flow from the backside of a departing low pressure system
over eastern Canada will trigger additional lake effect snow showers
mainly downwind of the lower Great Lakes early today, before a large dome
of high pressure building in from the southwest shuts off the lake effect
snow machine by this afternoon.  Passing snow showers can be expected
across the interior Northeast and much of Maine today before tapering off
early on Monday but a lingering polar front will keep a chance of snow
showers near the Canadian border into Tuesday,  Meanwhile, a large dome of
cold air behind the departing low pressure system will continue to surge
into the Deep South today, where numerous Freeze Warnings are in effect
from north Texas to the North Carolina coast through Monday morning. A
handful of record breaking cold min and max temps are expected across the
South this morning and Monday morning. The abnormally cold temperatures
extends as far south and west as West Texas, where snow fell in the higher
terrain and Big Bend early this morning. The dome of below normal
temperatures will linger through Monday across the South while the Midwest
and Northeast gradually moderate to more seasonal temperatures by Monday
afternoon and into Tuesday. 

After a tranquil Saturday, active weather is expected to overspread much
of the West to close out the weekend and begin the new week.  The first in
a series of storm systems is set to usher Pacific moisture into California
today and then spread north quickly up the Pacific Northwest later today
and into tonight.  The heaviest snowfall is once again forecast for the
Sierra Nevada where an additional foot can be expected to fall in the
higher terrain today along with wind gusts reaching as high as 50 mph. 
Moisture associated with this storm system will spill into the Great Basin
and the Rockies on Monday, resulting in periods of mountain snow and
valley rain showers. Snowfall totals are forecast to surpass a foot in the
higher elevations of the Great Basin, the Wasatch, and the western
Colorado Rockies. Periods of mountain snow look to continue over the
Rockies late Monday and into Monday night, while the next Pacific storm
system approaches California on Tuesday. Not only will there be mountain
snow and valley/coastal rainfall, but temperatures will remain abnormally
cool throughout the West into the first half of the week.  Over the
northern High Plains, the northern edge of this moisture plume is forecast
to begin organizing across the northern High Plains Monday night into
early Tuesday as a low pressure system starts to take shape over the
central High Plains.

Farther south, a cold front will continue its march south off South
Florida today with scattered showers and a few thunderstorms expected as
far north as northern Florida today.  By Monday, the front will be well
south and east of Florida, with residual showers on Monday dissipating or
moving out to sea by Monday afternoon as high pressure builds in from the
north.

Kong/Mullinax


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