Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
254 AM EST Wed Jan 04 2023

Valid 12Z Wed Jan 04 2023 - 12Z Fri Jan 06 2023

...Heavy snow and rain/freezing rain over parts of the Upper Mississippi
Valley/Upper Great Lakes begins to wind down...

...There is a Slight Risk of severe thunderstorms over parts of the
Southeast/Eastern Gulf Coast on Wednesday...

...There is a Moderate Risk of excessive rainfall over parts of the
California Coast on Wednesday and a Slight Risk of excessive rainfall over
parts of California on Thursday...

... Snow for the Sierra Nevada Mountains, Great Basin, Southwest, and
Central Rockies; Temperatures will be 15 to 25 degrees above average from
Lower Great Lakes/Ohio Valley eastward to parts of the
Northeast/Mid-Atlantic...

On Wednesday, a storm over parts of the Upper/Middle Mississippi Valley
will slowly move off the East Coast by Friday. The system will produce
heavy snow over parts of the Upper Mississippi Valley/Upper Great Lakes
through Thursday morning. Snow will linger over the Great Lakes/Ohio
Valley on Thursday as the storm moves eastward into the Northeast. Rain
over the Lower Great Lakes will move into the Northeast by Wednesday
afternoon. In addition, areas of rain/freezing rain will develop over part
of Northern New England. Rain and snow will linger over parts of the
Northeast, with a few pockets of rain/freezing rain over Northern New
England. Light snow and rain will linger into Friday morning over the
Northeast. The snow will result in reduced visibility and hazardous
driving conditions. Additionally, temperatures will be 15 to 25 degrees
above average ahead of the front from Lower Great Lakes/Ohio Valley
eastward to parts of the Northeast/Mid-Atlantic.

Furthermore, moisture from the Gulf of Mexico will northward pooling along
the associated front, producing showers and severe thunderstorms over the
Southeast on Wednesday. Therefore, the SPC has issued a Slight Risk of
severe thunderstorms over the Southeast/Eastern Gulf Coast from Wednesday
through Thursday morning. The hazards associated with these thunderstorms
are frequent lightning, severe thunderstorm wind gusts, a few tornadoes,
and a minimal threat of hail.

In addition, the showers and thunderstorms will produce moderate to heavy
rain. Therefore, the WPC has issued a Marginal Risk of excessive rainfall
over parts of the Southeast/Eastern Gulf Coast from Wednesday through
Thursday morning. The associated heavy rain will create localized areas of
flash flooding, affecting areas that experience rapid runoff with heavy
rain. The showers and thunderstorms will move off the Southeast and
Mid-Atlantic Coast by Thursday morning.

Meanwhile, a front will approach the West Coast on Wednesday. Ahead of the
front, a plume of moisture will move into California producing heavy rain.
Therefore, the WPC has issued a Moderate Risk of excessive rainfall over
parts of the California Coast from Wednesday into Thursday morning. The
associated heavy rain will create numerous areas of flash flooding.
Furthermore, many streams may flood, potentially affecting larger rivers.

Additionally, heavy snow will return to the Sierra Nevada Mountains on
Wednesday. Late Wednesday afternoon, coastal rain and higher-elevation
snow will also return to the Pacific Northwest. In addition, a few patches
of rain/freezing rain will develop over interior Washington State
overnight Wednesday into Thursday morning.

On Thursday, rain and higher-elevation snow continue over California.
However, the threat of excessive rainfall decreases slightly. Therefore,
the WPC has issued a Slight Risk of excessive rainfall on Thursday into
Friday 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. The heavy snow continues over the Sierra Nevada
Mountains. Overnight Thursday, the snow and rain mostly end over
California. The coastal rain continues over the Pacific Northwest into
Friday morning. During the late afternoon Wednesday, snow will move into
the Great Basin and parts of the Southwest and the Central Rockies by
Friday 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