Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Nov 19 2024
Valid 12Z Tue Nov 19 2024 – 12Z Thu Nov 21 2024
…Powerful Pacific low pressure system to produce significant high wind
impacts and heavy mountain snow across the Northwest, while a strong
atmospheric river takes aim at northern California by Wednesday…
…Potent storm system over the northern Plains to produce gusty winds and
locally heavy snow throughout the region before a redeveloping area of low
pressure brings unsettled weather to the Great Lakes, central
Appalachians, and Northeast from midweek onward…
…Heavy rain and flash flooding potential continues throughout portions
of the central and eastern Gulf Coast today…
No shortage of active weather across the Nation this week as two separate
strong low pressure systems produce hazardous conditions in the form of
high winds, heavy rain, and snowfall. Starting with the Pacific Northwest,
a rapidly strengthening and extremely powerful low pressure system
forecast to pass roughly 300 miles west of the Olympic Peninsula tonight
is anticipated to begin impacting the region today. Damaging winds with
gusts up to 70 mph are possible across northern California, as well as
parts of Oregon and Washington, with the highest winds expected along the
coast and high terrain. These winds are likely to produce numerous power
outages and tree damage in the most impacted regions. When combined with
heavy snowfall at the higher elevations, blizzard conditions are in the
forecast throughout the Washington Cascades. As an associated frontal
boundary slides southeastward and stalls near northern California on
Wednesday, a deep and continuous plume of anomalous atmospheric moisture
content will flow into the Redwood Coast of California and northern
mountain ranges of the Golden State. Heavy rain and rising snow levels
will increase the threat of numerous floods and potential mudslides,
exacerbated by the duration of heavy rainfall through the end of the week.
In fact, WPC has issued a High Risk (level 4/4) of Excessive Rainfall
across parts of northwest California on Thursday in order to further
highlight this flooding threat. Residents and visitors throughout the
Northwest are urged to have multiple ways to receive warnings, listen to
advice from local officials, and avoid traveling through hazardous weather
conditions if possible.
In the north-central U.S. another potent low pressure system is lifting
northward and producing unsettled weather of its own across the Upper
Midwest and northern Plains today. A tight pressure gradient being
produced by the storm is forecast to create strong winds across much of
Nebraska, eastern Montana, and the Dakotas through Wednesday with maximum
wind gusts up to 65 mph possible. Strong winds may also overlap with
moderate to locally heavy snow throughout North Dakota and northwest
Minnesota as the storm system stalls tonight over south-central Canada.
Probabilities for at least 6 inches of total snowfall are high (>70%)
across northern North Dakota. Meanwhile, scattered showers are forecast to
spread eastward into the Midwest, Great Lakes, and eventually the
Mid-Atlantic ahead of an advancing cold front today. By Wednesday night, a
redeveloping low pressure system rapidly strengthening over the Great
Lakes will help produce another round of precipitation over the Great
Lakes, central Appalachians and Northeast through the end of the week. The
greatest impacts from this precipitation is expected throughout the higher
elevations of West Virginia and western Maryland, where up to a foot of
snowfall is possible through Friday.
Elsewhere, heavy rain and a risk for scattered flash floods remains a
concern across the central and eastern Gulf Coast as a cold front, weak
area of low pressure, and ample atmospheric moisture content spark
numerous showers and thunderstorms capable of containing intense rainfall
rates through tonight. The greatest risk for flash flooding specifically
exists from far eastern Louisiana to the western Florida Panhandle, with
urban and poor drainage regions most susceptible to rapid water rises.
Temperatures will be on a roller coaster ride this week as well above
average temperatures are found in the East before an advancing cold front
knocks readings down below average by Thursday. Meanwhile, cooler
temperatures over much of the West are forecast to return to near normal
as upper ridging builds into place.