Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
309 PM EST Sat Dec 20 2025

Valid 00Z Sun Dec 21 2025 - 00Z Tue Dec 23 2025

...Active pattern to continue for the West Coast with heavy rainfall and
higher elevation heavy snow over the next couple of days...

...Flood potential will increase across central/northern California on
Sunday and Monday with several inches of rain forecast...

...Temperatures will be well above average from the Intermountain West
into the southern to central High Plains...

The jet stream will generally be oriented from west to east across the
lower 48 through early this week which will keep locations from central
California into western Washington and the interior western U.S. fairly
active. An atmospheric river will take aim at California with heavy
precipitation beginning tonight from central to northern California. Snow
levels will be fairly high across the Sierra Nevada which will keep the
majority of precipitation in the form of rain below ~9,000 feet through
Sunday. By Monday morning, the atmospheric river and axis of heaviest
rainfall will temporarily shift to between San Francisco and Point
Conception with snow levels falling to about 6,000 to 7,000 feet for the
central to northern Sierra Nevada. Locally heavy rainfall rates and
rainfall totals through Monday evening are likely to bring 5 to 10 inches
of rain for the Sierra Nevada and at least 3 to 6 inches for the Coastal
Ranges. While the axis of heaviest rainfall will meander north/south over
the next couple of days, persistent rainfall will begin to lead to
flooding of smaller rivers/creeks and into urban areas.

Meanwhile, locations to the north, from western Oregon and western
Washington, will see continued onshore flow but cooler temperatures will
result in greater coverage of snow into the mountains. At least 1 to 3
feet of additional snow is expected for the higher elevations of the
Olympics and Cascades through Monday night. Snow levels will lower with
northward extent and will be as low as 1,000 feet above sea level at times
for western Washington.

Regarding temperatures, highs are expected to be 15 to 30+ degrees above
average from portions of the Intermountain West into the central High
Plains through Monday due to the onslaught of Pacific air. Several daily
record high temperatures are likely to be set across these areas over the
next few days, likely continuing into mid-week.

Otto


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