Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Sat Sep 04 2021

Valid 00Z Sun Sep 05 2021 - 00Z Tue Sep 07 2021

...Organized thunderstorms expected to bring heavy rain and areas of flash
flooding tonight and into Sunday from the Southern Plains to the Ohio &
Tennessee Valleys...

...Seasonally cool from the Central Plains to Northeast but hot and humid
across the southern Plains; increasingly hot throughout the West...

...Occasional showers and storms in the Lower Mississippi Valley; raging
wildfires out West to continue causing poor air quality along the West
Coast and into the Intermountain West...

A frontal system sweeping across the Nation's Heartland is forecast to
cause unsettled weather from the Great Lakes and Middle Mississippi Valley
to the Southern Plains tonight and into Sunday. Some storms over central
Oklahoma, the Ozarks, and extending up towards the Mississippi-Ohio River
confluence could become severe and/or produce localized areas of flash
flooding. In fact, a Slight Risk for Excessive Rainfall is in place for
parts of these areas into early Sunday morning. Locally heavy showers and
storms extend as far west as New Mexico and southeast Arizona. Localized
areas of flash flooding are possible, especially in eastern New Mexico
where Flash Flood Watches are in effect, along with a small Slight Risk
area for Excessive Rainfall, through tonight. By Sunday, a low pressure
system tracking through Ontario will send its cold front east into the
Ohio Valley and farther south into the Southern Plains and Lower
Mississippi Valley. These regions can expect hit-or-miss showers and
storms to develop with the heaviest rainfall likely to transpire in the
Tennessee Valley and northern Mississippi and Alabama. Wet weather is also
a good bet in the Northeast late Sunday and early Monday morning, but once
the front exits to the east, drier conditions should return the second
half of Labor Day.

Temperature-wise, the West continues to heat up as a building ridge of
high pressure becomes centered over Nevada and central California on Labor
Day. Beneath this intensifying ridge aloft, stifling heat will overtake
much of the West Coast with the hottest conditions focused in central
California and the Great Basin. Excessive Heat Watches have been posted
for parts of the Mojave Desert where high temperatures soaring into the
110s are likely starting Labor Day and continuing into Tuesday. Heat
Advisories are also in effect in the San Joaquin Valley for Labor Day as
well. The heat across the West spills into the northern High Plains by
Labor Day where high temps look to range between 10-15 degrees above
normal. Meanwhile, sultry conditions continue throughout south Texas and
into the Lower Mississippi Valley this afternoon and into Sunday. The
aforementioned cold front described above will help cool the South-Central
U.S. to more seasonal levels by Labor Day.

Elsewhere, a quasi-stationary front lingering near the northern Gulf Coast
and over central Florida begins to dissipate by Labor Day. Eventually, the
cold front to the north will approach and ignite additional showers and
storms near the central Gulf Coast on Labor Day. This means daily rounds
of pop-up showers and storms each afternoon, some of which could contain
heavy downpours. One more day of scattered showers and storms are on tap
in southern New Mexico and into the Texas Panhandle on Sunday but should
decrease in coverage and intensity by Labor Day. Lastly, Air Quality
Alerts remain in effect across parts of the Pacific Northwest and
California due to ongoing bouts with smoke from ongoing wildfires.

Mullinax