…Widespread showers and storms across much of the eastern and southern
U.S Friday….
…Threat for isolated to scattered flash flooding for portions of the
Mid-Atlantic and south Texas with a severe weather threat across the
Tennessee Valley/southern Appalachians through Friday morning, then an
isolated threat for the the Northeast and Gulf states/Southeast through
Sunday morning…
…Temperatures remain below average across much of the eastern and
southern U.S. while much above average expand across the north-central and
western U.S….
A slow moving front, from the Northeast trailing trough the eastern states
and westward across the Gulf states and Texas, will be the focus for
convective development as
moist Gulf return flow persists. Some of these storms have the potential
to produce rainfall rates of 0.5 inch/hour or greater given the abundant
moisture availability and with the slow motion expected, there will be an
increased threat for isolated instances of flash flooding. WPC has a broad
Marginal Risk today that covers much of the eastern third of the country
as well southern Texas and extreme southeast New Mexico. Higher moisture
in an airmass undisturbed by the previous days convection over south Texas
will also lead to widespread storms with a locally higher threat for
heavier downpours and scattered flash flooding, with a Slight Risk in
effect. In addition, a couple areas of severe weather are expected. First,
locally stronger winds associated with one of the upper-level waves and
sufficient instability with warming temperatures ahead of the cold front
will lead to a cluster of strong to severe storms from the Tennessee
Valley east through the southern Appalachians. The Storm Prediction Center
has introduced a Slight Risk of severe weather (level 2/5) mainly for the
threat of very large hail along with damaging wind gusts. Second, an
upper-level shortwave passing over the Rio Grande Valley/south Texas will
bring the threat for some strong to severe storms here as well, with
another Slight Risk in place for additional instances of large hail and
damaging winds.
The progression of this front will be slightly more progressive with the
leading low as it advances north/northeast near the coast however the
movement across the Southeast will be slow. This will maintain an elevated
threat for isolated areas of flash flooding for the Gulf/Southeast and for
the Northeast through the weekend. Elsewhere, lingering moisture along the
Central/Southern Rockies and the adjacent High Plains will lead to some
scattered storms today through Friday. An upper-level shortwave and
accompanying surface frontal system passing from the Northern Rockies/High
Plains today to the Upper Midwest Friday will bring a chance for some
isolated showers. Mostly dry conditions are expect across the Plains,
Midwest and the Great Basin/West Coast.
The consolidating upper-trough across much of the eastern/southern U.S.
while a ridge builds over the western/northern U.S. will lead to some
significant variations in temperatures through the weekend. Under the
troughing, below average temperatures will be felt across much of the
Great Lakes/Northeast southwest through the Ohio/Middle Mississippi Valley
and for the Central/Southern Plains. Daily maximums in the 50s and 60s
will be common for more northern locations with 60s and 70s from the Ohio
Valley southwards. Conditions along the East Coast will be a bit closer to
average ahead of the approaching cold front, with highs in the 60s and 70s
for the Mid-Atlantic and 70s and 80s into the Southeast. In contrast, well
above average temperatures will expand in coverage across the Northern
Plains/Upper Midwest and Interior West/West Coast. Forecast highs are
generally in the 70s and 80s with 90s in the central California Valleys
and low 100s into the Desert Southwest.
Campbell/Putnam
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
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