125
FXUS01 KWBC 120819
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
318 AM EST Wed Feb 12 2025

Valid 12Z Wed Feb 12 2025 - 12Z Fri Feb 14 2025

...Moderate Risk of excessive rainfall over parts of Southern
California on Thursday; There is a Slight Risk of excessive
rainfall over parts of Northern/Central California and Lower
Mississippi Valley to the Southern Appalachians on Wednesday...

...Rain/freezing rain over parts of the Mid-Atlantic/Central
Appalachians to Lower Great Lakes with 0. 25 inches of ice
accumulations possible on Wednesday: Rain/freezing rain over parts
of the Southern Plains to the Ohio Valley/Great Lakes with 0. 10
inches of ice accumulations possible on Wednesday...

...Rain/freezing rain over parts of the Pacific Northwest with 0.
10 inches of ice accumulations possible on Wednesday into
Thursday; Rain/freezing rain over parts of Northeast the with 0.
01 inches of ice accumulations possible on Thursday...

...There is a Slight Risk of Severe Thunderstorms over parts of
the Lower Mississippi Valley and the Southeast on Wednesday...

...Temperatures will be 25 to 35 degrees below average across the
Northern Rockies eastward to the Upper Mississippi Valley and
southward to the Southern Plains...

On Wednesday, an Arctic high over the Northern Intermountain
Region to the Northern Plains will slowly move southeastward to
the Ohio Valley/Central Appalachians by Friday. The cold air
associated with the high will bring temperatures 25 to 35 degrees
below average across the Northern Rockies eastward to the Upper
Mississippi Valley and southward to the Southern Plains. The cold
temperatures have prompted an Extreme Cold Warning over the
Northern Rockies to the Northern Plains.

South of the Artic High, a front extending from the Southeast to
the Southern Rockies and then to the Great Basin will spawn a wave
of low pressure over the Tennessee Valley that moves northeastward
to southeast Ontario, Canada, by Thursday and then into
Southeastern Canada by Friday. On Wednesday evening, the
associated front over the Tennessee Valley will move off the
Eastern Seaboard by Thursday evening.

The system will spread snow from the Central Plains into the Great
Lakes on Wednesday and into far northern New England by Wednesday
night and early Thursday. In Addition, bursts of heavy snow,
accumulating at times to an inch per hour, may lead to hazardous
driving conditions and disrupt travel. Heavier snow rates should
develop in time for the evening rush hour in Milwaukee, Chicago,
Grand Rapids, and Detroit, among other locations. Plan ahead if
you are commuting. Further, a wintry mix of snow, sleet, and
freezing rain on the south side of the main snow band will lead to
hazardous travel conditions elsewhere in the Midwest and Northeast.

Moreover, a damaging freezing rain, ice event, will continue on
Wednesday, particularly in the Blue Ridge from far northwest North
Carolina into western Virginia and the Allegheny Mountains near
the West Virginia and Virginia border, with 0.25 inches of ice
accumulations. Dangerous travel is expected; power outages and
tree damage are likely.

Furthermore, moisture from the Gulf will stream northward over the
Southern Plains, Lower Mississippi Valley, and the Southeast on
Wednesday. The moisture will aid in producing showers and severe
thunderstorms over parts of the Lower Mississippi Valley and
Southeast. Therefore, the SPC has issued a Slight Risk (level 2/5)
of severe thunderstorms over parts of the Lower Mississippi Valley
and Southeast through Thursday morning. The hazards associated
with these thunderstorms are frequent lightning, severe
thunderstorm wind gusts, hail, and a few tornadoes.

Moreover, the showers and thunderstorms will have heavy rain.
Therefore, the WPC has issued a Slight Risk (level 2/4) of
excessive rainfall over parts of the Lower Mississippi Valley into
the Southern Appalachians through Thursday morning.  The
associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, small streams, and low-lying
areas the most vulnerable. On Thursday, the threat of severe
thunderstorms and excessive rainfall will decrease to a marginal
risk over the Southeast.

Meanwhile, on Wednesday, a storm over the Eastern Pacific will
begin to move onshore over the West Coast. The system will produce
rain and higher-elevation snow over parts of Central/Southern
California. As the storm moves farther inland, heavy rain will
arrive late Wednesday Night in Central California and then spread
inland into the Central Valley and down the coast to Southern
California on Thursday. The heavy rain may cause flooding in urban
areas and small streams, as well as some minor river flooding.
Therefore, the WPC has issued a Slight Risk (level 2/4) of
excessive rainfall over parts of Central California through
Thursday 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 risk of flash flooding will be highest in and near recent burn
scar areas in Southern California. Flooding may include debris
flows. People living in or near recently burned areas should
listen carefully to instructions from local officials.

On Thursday, the threat of excessive rainfall increases over
Southern California. Therefore, the WPC has issued a Moderate Risk
(level 3/4) of excessive rainfall over parts of Southern
California from Thursday into Friday morning. Numerous flash
flooding events are possible. Many streams may flood, potentially
affecting larger rivers. Flooding may include debris flows in or
near recently burned areas.

Also, on Thursday, coastal rain and higher-elevation snow will
move into the Pacific Northwest. Additionally, snow will spread
into much of the Western U.S. Thursday and Friday. The heaviest
snow is expected in the Sierra Nevada and Northern California
mountains. Snow levels will rise through the event, but heavy snow
will likely cause dangerous travel at many mountain passes due to
snow-covered roads and low visibility. Significant snow is also
likely in the mountains of Utah and western Colorado. Ice
accumulations are possible in northwest Oregon.


Ziegenfelder


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