Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
258 AM EST Fri Dec 30 2022

Valid 12Z Fri Dec 30 2022 - 12Z Sun Jan 01 2023

...There is a Slight Risk of excessive rainfall over parts of Northern
California and the Central Gulf Coast...

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

...Temperatures will be 15 to 25 degrees above average from Lower Great
Lakes/Ohio Valley into the Northeast...

Low pressure develops along the Central Gulf Coast Friday night and moves
northeastward, merging with a second area of low pressure over the
Northeast by Sunday. The system will produce heavy rain and thunderstorms
over the Central Gulf Coast. Therefore, the WPC has issued a Slight Risk
of excessive rainfall over parts of the Central Gulf Coast Friday into
Saturday morning. The associated heavy rain will create mainly localized
areas of flash flooding, with urban areas, roads, and small streams the
most vulnerable. On Saturday, the threat of excessive rainfall ends. The
showers and thunderstorms will move eastward into the Southeast. Rain will
also develop over parts of the Great Lakes to the Ohio Valley along a cold
front on Friday and the rain will slowly move into the Northeast by
overnight Saturday. Ahead of the front, temperatures will be 15 to 25
degrees above average from Lower Great Lakes/Ohio Valley into the
Northeast on Friday.

Meanwhile, a front moves onshore over California, moving to the Central
Rockies/Southwest by Sunday. A plume of moisture will move onshore over
California with the boundary. The system will produce heavy rain over
parts of California through Sunday. Therefore, the WPC has issued a Slight
Risk of excessive rainfall over parts of Northern/Central California on
Friday into Saturday morning.

The associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, and small streams the most vulnerable.

On Saturday, the heavy rain will continue over parts of Northern/Central
California and move into Southern California. Therefore, the WPC has
issued a Slight Risk of excessive rainfall over parts of Northern/Central
California, expanding into Southern California from Saturday to Sunday
morning. The associated heavy rain will create mainly localized areas of
flash flooding, with urban areas, roads, and small streams the most
vulnerable.

In addition, coastal rain and higher-elevation snow will develop over
parts of the Pacific Northwest through Friday night and begin to taper off
on Saturday. Snow will also develop over parts of the Northern
Intermountain Region and the Great Basin through Saturday morning. On
Saturday, the associated cold front moves across California into the
Southwest. As a result, snow levels lower, with the front producing heavy
snow over the Sierra Nevada Mountains Saturday night into Sunday. Snow
will also continue over the Great Basin and the Central Rockies. 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 morning. The
system will produce light snow over parts of the Upper Mississippi
Valley/Upper Great Lakes overnight Saturday into Sunday morning. The snow
will result in reduced visibility and hazardous driving conditions.


Ziegenfelder

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