Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EST Fri Mar 03 2023

Valid 12Z Fri Mar 03 2023 - 12Z Sun Mar 05 2023

...Deepening low-pressure system will produce a multitude of weather
hazards across the eastern third of the country...

...Above-average temperatures return to eastern half of country this
weekend, while the West remains cool and unsettled...

...Rain and additional heavy mountain snows to return to the West Coast on
Saturday...


A potent system is forecast to produce a multitude of weather hazards
throughout the eastern third of the country over the next 24 hours as the
storm rapidly deepens and approaches all-time record low sea level
pressure values for portions of the Ohio and Missouri valleys. The ongoing
severe weather and flash flood risk associated with the system will
continue through the early Friday morning hours across the Lower
Mississippi Valley, with the threat shifting northeastward throughout the
day as the strengthening low lifts northward into the Ohio Valley.
Thunderstorms developing ahead of the eastward progressing cold front will
have the potential to produce damaging wind gusts, small hail, and
isolated tornadoes on Friday, resulting in the Storm Prediction Center
issuing an Enhanced Risk of Severe Thunderstorms for eastern portions of
the Tennessee Valley. Prolonged heavy rainfall rates associated with
training showers and thunderstorms may also lead to flash flooding
throughout much of the Mid-Mississippi and Ohio Valleys stretching
eastward into the Mid-Atlantic, with a Moderate Risk of Excessive Rainfall
covering portions of northeastern Arkansas, southeastern Missouri,
southern Illinois, and southern Indiana. Furthermore, strong synoptic wind
gusts will also be likely as a result of the deepening system, with
expansive Wind Advisories and High Wind Warnings covering a large swath of
the region.

During the Friday afternoon hours, heavy snow is expected to develop on
the northern fringe of the precipitation field across northern Illinois,
northern Indiana, and southern Michigan as cold air wraps around the
deepening low. A stripe of 6"+ snow totals is possible through Saturday
morning, with localized areas in southern Michigan forecast to receive
upwards of 8-12"+. As the system quickly tracks northeastward, the threat
of wintry precipitation will shift into the Appalachians and Northeast,
with a broad swath of 6-12"+ forecast across much of Upstate New York, New
Hampshire, Vermont, northern Massachusetts, and southern Maine. Further
south, precipitation will likely begin as freezing rain and sleet across
Pennsylvania and the central Appalachians, with ice accretions upwards of
0.10" possible, with as much as 0.25-0.5" across higher terrain.
Conditions are expected to improve during the early Sunday morning hours
as the system departs the East Coast.

In the wake of the potent system, a strengthening upper-level ridge in the
eastern half of the country will lead to well above average temperatures
(10-20 degrees F above average) to end the weekend across much of the
southern Plains, Midwest, Ohio Valley, and Southeast. Further west,
temperatures will remain unseasonably cold as persistent upper-level
troughing continues to produce cool and unsettled weather.

A storm system tracking southward across the Pacific Northwest and
California on Saturday will produce moderate to heavy precipitation across
coastal portions of the region, with heavy snow possible in the higher
terrains of the Sierra Nevada and Cascade ranges. An additional several
feet of snow will be possible in these areas, with the heaviest of these
totals likely in the northern Sierra Range. On Sunday, precipitation will
spread inland, with heavy snow possible in the higher terrains of the
Intermountain West.

Russell


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