Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
132 PM EST Sat Dec 02 2023

Valid 00Z Sun Dec 03 2023 - 00Z Tue Dec 05 2023

...A multi-day atmospheric river event will continue to impact the
Northwest with heavy rain and significant mountain snowfall this weekend...

...Unsettled weather forecast across the eastern third of the country with
heavy rain potential along the Gulf Coast and Southeast; wintry weather is
expected from parts of the Midwest and Great Lakes to northern New
England...

...Generally milder than normal temperatures expected for across most of
the Lower 48...


The ongoing atmospheric river event in the Northwest is expected to
continue through the rest of the weekend and into early next week. Waves
of shortwave energy and associated surface low pressure systems will
continue to bring a plume of anomalous Pacific moisture into the Pacific
Northwest and Northern Rockies this weekend. Lower snow levels will allow
for heavy snowfall across the Cascades through Sunday. There is a high
chance (>90%) of at least 24" of total snowfall for Cascade passes,
including I-90. Snow levels rise above 4000 feet tonight which will end
the heavy snow threat over the passes. Travel will be difficult and
hazardous. Increasing wind with periods of of heavy snow will produce
areas of blowing snow over the higher terrain of the Northern Rockies.
There is a high chance (>70%) of 1-3 feet of snow in the higher terrain
through Sunday.

Heavy rain at the lower elevations of the Pacific Northwest may cause
Flash Flooding issues. Several issues of rainfall along the Pacific
Northwest coastline and inland areas will support a Slight Risk (at least
15%) of Excessive Rainfall leading to Flash Flooding by Sunday. There is a
Marginal Risk in effect for much of western/coastal Oregon and parts of
the southern Cascades for tonight. Several inches of rain in the lowlands
and the rising snow levels tonight into Sunday will likely produce minor
to moderate river flooding late this weekend into next week in western
WA/OR. The moisture plume redirects northward over Washington state by
early this coming week.

Showers and scattered thunderstorms spread from the Southeast through the
Mid-Atlantic and into the Northeast through Sunday. A trailing low
pressure system will generate rain/snow showers across the Upper Great
Lakes/Midwest and Ohio Valley. Heavy snow will develop over northern New
England Sunday afternoon into evening and continue through Monday. The
heaviest snow will occur over northern Vermont/New Hampshire through
inland Maine. Widespread record warm low temperatures will likely be
realized over much of the Southeast and Mid-Atlantic tonight as clouds and
rainfall work to keep temperatures from falling much from their daytime
highs. Much of the rest of the country will warm up heading into the work
week.


Kebede


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