Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
309 AM EST Sat Feb 22 2020

Valid 12Z Sat Feb 22 2020 - 12Z Mon Feb 24 2020

...An energetic storm system expected to impact the Southwest on Saturday,
Central Rockies/Plains on Sunday, and into the Mid-Mississippi Valley by
Monday...

...Rain and mountain snow return to the Northwest on Sunday reaching the
northern High Plains by Monday...

After a day of tranquil conditions across much of the country on Friday,
unsettled weather is expected to move quickly into the southwestern U.S.
followed by the Pacific Northwest this weekend.  A large high pressure
system responsible for the tranquil weather will gradually weaken and then
slide off the East Coast during the next few days.  Chilly conditions
across the eastern half of the country will gradually moderate to above
normal levels by Monday as winds shift to a more southerly direction. 
Meanwhile, a low pressure system that has been developing over the eastern
Pacific is taking aim at the southwestern U.S. This storm system will tap
into moisture originating deep from the tropical Pacific and begin to
spread rain into the Desert Southwest today with the possibility of
thunderstorms this afternoon and evening across portions of Arizona and
New Mexico. The heaviest rainfall looks to be concentrated in the higher
elevations of western New Mexico and south-central Arizona where rainfall
totals ranging between 1 and 2 inches is possible. A Slight Risk for
Excessive Rainfall has been issued for these areas due to heavy rainfall
rates potentially causing areas of flash flooding today.  In addition,
mountain snow is expected from the southern Sierra Nevada and the Wasatch
to the Colorado Rockies through this weekend.

By Sunday, this storm system is forecast to intensify as it moves into the
central High Plains.  Showers and some thunderstorms are expected to
quickly develop and expand across the central Plains toward the
Mid-Mississippi Valley through Sunday night. Some wintry precipitation is
also possible farther to the north from across the central Plains into the
upper Midwest and the lower Great Lakes Sunday night into Monday morning. 
The southern Appalachians could also see wintry precipitation developing
Monday morning as thunderstorms will likely be moving across the lower to
mid-Mississippi Valley ahead of the intensifying storm.

Farther north, another low pressure system will cause an increase in
showers and and mountain snow over the Pacific Northwest on Sunday. The
Olympics and Cascades will receive more mountain snow while the valleys
and coastal areas see rain. The storm system will then track into the
northern Rockies Sunday night leading to more areas of mountain snow.  The
snow will then expand farther east into the northern Plains as the storm
center moves into the northern High Plains by Monday morning.

Kong


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