Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
313 PM EDT Fri Apr 21 2023

Valid 00Z Sat Apr 22 2023 - 00Z Mon Apr 24 2023

...Numerous showers and thunderstorms continue eastward along a cold front
from the Mississippi and Ohio Valleys today to the East Coast this weekend
with severe weather and flash flooding possible...

...Dome of high pressure to deliver widespread swath of abnormally chilly
temperatures from the Nation's Heartland today and Saturday to the East
Coast by Sunday...

...Mountain snow and coastal/valley showers for the northern/central
Rockies and Pacific Northwest; unsettled and stormy second half of the
weekend for southern and central Texas...

A frontal system tracking east through the eastern third of the U.S. will
be responsible for producing showers and thunderstorms from as far south
as South Texas and the Lower Mississippi Valley to the Ohio Valley and
eastern Great Lakes. The Storm Prediction Center (SPC) has a Slight Risk
for severe weather in the Lower Rio Grande Valley, as well as a pair of
Marginal Risks in the Lower Mississippi Valley and the Upper Ohio Valley.
The Weather Prediction Center (WPC) also has an expansive Marginal Risk
area through the Lower Mississippi, Tennessee, and Ohio Valleys. As the
front marches east on Saturday, the atmosphere will be primed to produce
more severe storms in the Southeast and Mid-Atlantic. SPC issued a Slight
Risk for severe weather from the coastal Carolinas on north to the
Washington D.C.-Baltimore metro area. The footprint of thunderstorms will
span from central Florida to the northern Mid-Atlantic with storms capable
of producing large hail, damaging wind gusts, and tornadoes. By Sunday,
the cold front will have passed through the Mid-Atlantic and Southeast,
but New England will still be dealing with rain as a new area of low
pressure forms along the southern New England coast. Ample moisture and
locally heavy rainfall rates has prompted WPC to issue a Marginal Risk of
Excessive Rainfall for much of southern and central New England for Sunday.

The aforementioned cold front sweeping through the eastern U.S this
weekend will also be introducing an exceptionally cold air-mass, in the
form of Canadian high pressure, through the Nation's Heartland this
afternoon. Temperatures are forecast to drop below freezing in parts of
the Central Plains Saturday morning, resulting in the issuance of Freeze
Warnings and Watches from eastern Kansas and Nebraska to portions of the
Middle Mississippi River Valley. This push of anomalously cooler
temperatures will make their way through the Ohio and Tennessee Valleys
tonight, then as far east as the Mid-Atlantic and Southeast by Saturday
evening. New England will remain under the influence of onshore flow,
keeping cooler than normal temperatures locked in over much of the region
throughout the duration of the weekend. Sunday has the best odds of the
two days this weekend to produce record cold daily maximum and minimum
temperatures. Record cold minimum temperatures are forecast in parts of
the Central Plains, with record cold daily maximum temps possible in the
Southern Plains.

Elsewhere, the Pacific Northwest and both the northern and central Rockies
will contend with occasional coastal/valley showers and mountain snow this
weekend. The first round of precipitation this evening and into Saturday
is due to an upper level disturbance passing through the Intermountain
West and a frontal boundary setting up along the front range slopes of the
northern Rockies. The next round of wet weather arrives Saturday and into
Sunday in the Pacific Northwest as a storm system in the northeast Pacific
ushers in more precipitation, as well as cooler than normal temperatures
by Sunday. Farther south, a frontal boundary west of the Rio Grande and a
broad troughing pattern over the Southwest will provide sufficient lift,
along with easterly flow providing a source of Gulf of Mexico moisture, to
produce widely scattered showers and thunderstorms across central and
southern Texas. WPC and SPC have issued Marginal Risks in south-central
Texas for both Saturday and Sunday, as storms will have the potential to
produce both locally excessive rainfall rates and severe weather.

Mullinax


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