Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
238 AM EST Sat Dec 31 2022

Valid 12Z Sat Dec 31 2022 - 12Z Mon Jan 02 2023

...There is a Slight Risk of excessive rainfall over parts of California...

...Snow for the Sierra Nevada Mountains, Great Basin, and Central
Rockies...

...Temperatures will be 15 to 20 degrees above average from
Central/Southern Plains into the Northeast...

Low pressure over the Central Gulf Coast Saturday moves northeastward,
merging with a second area of low pressure over the Northeast overnight
Saturday. The system will produce showers and thunderstorms over the
southeastern section of the country through late Saturday night. Rain will
also develop over parts of the Great Lakes to the Ohio Valley along a cold
front on Saturday, moving into the Northeast/Mid-Atlantic by Saturday
afternoon into evening. Ahead of the front, temperatures will be 15 to 20
degrees above average from Central/Southern Plains into the Northeast on
Saturday. The rain will move off the East Coast by Sunday morning.

Meanwhile, a front from California to the Central Rockies on Saturday will
move eastward to the Southern High Plains by Monday. A plume of moisture
will move onshore over California with the boundary, producing heavy rain
over parts of California through Sunday morning. Therefore, the WPC has
issued a Slight Risk of excessive rainfall over parts of Central/Southern
California on Saturday into Sunday morning. The associated heavy rain will
create mainly localized areas of flash flooding, with urban areas, roads,
small streams, and burn scars the most vulnerable. On Sunday, the threat
of excessive rainfall ends over California. However, the rain will
continue over Southern California, ending by Sunday evening.

In addition, coastal rain and higher-elevation snow will develop over
parts of the Pacific Northwest on Saturday and begin to taper off on
Saturday evening. Snow will also develop over parts of the Northern
Intermountain Region and likewise taper off on Saturday evening. Snow will
also develop over parts of the Great Basin through Monday morning.
Additionally, the associated cold front moves across California into the
Southwest on Saturday. As a result, snow levels lower, with the front
producing heavy snow over the Sierra Nevada Mountains Saturday afternoon
into Sunday afternoon. Snow will also develop over the Central Rockies
moving into parts of the Southwest and Southern Rockies by Sunday evening.
The snow will continue over the region into Monday. The snow will result
in reduced visibility and hazardous driving conditions.

Furthermore, on Saturday, weak low pressure over the Northern Plains will
move northeastward into Western Ontario, Canada, by Sunday evening. The
system will produce light snow over parts of the Upper Mississippi
Valley/Upper Great Lakes Saturday into Sunday evening. Also, light snow
will develop overnight Sunday into Monday over the higher elevations of
the interior Northeast. The snow will result in reduced visibility and
hazardous driving conditions. Moreover, overnight Sunday, moisture from
the Western Gulf of Mexico will surge northward over the Western Gulf
Coast/Lower Mississippi Valley producing showers and thunderstorms over
the area on Monday morning.


Ziegenfelder


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