…Improvement in fire weather conditions across southern California…
…Arctic front to bring hazardous cold to much of the nation and
impactful winter weather from the Rockies to the Northeast…
Benign conditions persist across most of the country today, and fire
weather conditions continue to improve in southern California as offshore
winds diminish. The only precipitation of note is in the Great Lakes,
central/northern Appalachians, and Mid-Atlantic where snow is falling
underneath an upper shortwave. Winter Weather Advisories and Winter Storm
Warnings are in effect for portions of the Appalachians where 5-10 inches
of snow, falling heavy at times, is expected. Snow will continue into
tonight and gradually taper off by Friday morning as the shortwave exits
the region to the east.
Friday will be the start of a significant shift in the weather pattern as
an Arctic frontal system drops south into north-central U.S. and
Northwest. The frontal system will quickly surge south and east through
the weekend, reaching all the way to the Gulf and East Coasts by early
next week. A frigid air mass will spread across most of the nation in the
wake of the front, and temperatures will be hazardously cold for many with
anomalies of 15-35 degrees below normal. The most extreme anomalies will
be in the Plains, but the coldest and most dangerous temperatures will be
across the northern tier. The Rockies, northern Plains, and Upper Midwest
should see minimum wind chills of -30 degrees or colder through this
weekend, which poses a great risk of hypothermia and frostbite to exposed
skin. Subzero wind chills are forecast to reach the southern Plains,
Mid-Mississippi Valley, and Ohio Valley by Sunday night.
In additional to hazardous cold, the Arctic frontal system will bring
wintry precipitation from the Rockies to the Northeast. Snow squalls will
be possible for the Rockies and northern Plains, and brief bursts of snow
and gusty winds in snow squalls could lead to reduced visibilities and
deteriorating road conditions tonight through Friday. WPC has initated Key
Messages for the dangerous cold and snow squall potential associated with
the Arctic front.
Ahead of the Arctic front, a wave of low pressure will move from the
southern Plains to the Southeast Saturday into Sunday, causing a warm
front to lift across these regions and trigger showers and thunderstorms.
Locally heavy rainfall will be possible in stronger storms and in areas
with training convection, which could lead to isolated instances of flash
flooding, mainly in urban and poor drainage areas.
The West Coast will largely be unaffected by this Arctic system.
Temperatures should remain near normal and dry weather is expected through
the weekend.
Dolan
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
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