Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
223 PM EDT Fri Sep 08 2023

Valid 00Z Sat Sep 09 2023 - 00Z Mon Sep 11 2023

...Severe storms possible today across portions of the Northeast, Mid
Atlantic, and from the Red River to the upper Texas and Louisiana coasts
...

...Dangerous heat will be abating across Northeast today but will continue
across south-central U.S. spreading into the Southwest...

...Increasing chance for heavy rain across portions of the Southeast on
Saturday, as well as the Central High Plains Sunday...

A cold front will stall across the Northeast, Mid-Atlantic into the
Carolinas later today and will remain a focus for daily rounds of showers
and thunderstorms through the weekend.  The extreme heat that has been
seen across the Northeast/Mid-Atlantic has pushed more offshore with only
a segment of southeast New England remaining under Heat Advisories for
today.  Still above normal temperatures (upper 80s to low 90s) and high
humidity across the region will support stronger thunderstorms today with
a Slight Risk of severe weather issued by the Storm Prediction Center
(SPC) from New England to Northern Virginia becoming a bit more scattered
across North Carolina and even Peninsular Florida where Marginal Risks are
posted.  A few of these cells may be intense enough for widely scattered
incidents of flash flooding across sloped terrain from New England through
the Smoky Mountains of TN/NC.

Through the weekend, temperatures will moderate back into the 80s but will
continue to help produce wide spread showers and thunderstorms.  A few of
those may be very slow moving particularly in the central to southern
Appalachians and adjacent Piedmont and may induce localized flash
flooding.  The Weather Prediction Center (WPC) has issued a Slight Risk of
Excessive Rainfall for those areas while a Marginal Risk of severe weather
covers much of the east coast from GA to ME.   By Sunday, the risk will
further diminish and Marginal Risks of excessive rainfall will continue
with slow moving thunderstorms across the central to northeastern
Appalachian mountains.

Further south, the frontal zone will dig toward the Gulf Coast, but lift
northward to a persistent surface low pressure across north Texas.  Very
high heat and some pooled moisture along the front from the Eastern Red
River through the Sabine River Valley in eastern Texas/western Louisiana
will result in high unstable air capable of stronger thunderstorms with
severe winds and hail.  As such, SPC has hoisted a Slight Risk across this
area for the remainder of today.   Extreme heat over 100-110F will exist
across much of Texas with much of the eastern half of the state being
under Excessive Heat Warnings.  A respite is coming as the low and frontal
zone slide southward through the weekend as the upper-level ridge/heat
dome starts to slide westward into New Mexico and the Southwest;
temperatures will remain above normal, particularly closer to the
Pecos/Rio Grande River, but only in the upper 90s/low 100s or about 5-10
degrees above normal not the 15-25 seen over the past few days.  By
Sunday, westerly flow aloft and cold front from the Northern Plains should
support stronger thunderstorms in an upslope regime out of Colorado into
the central Plains, Marginal Risk of severe weather is possible both days,
but WPC has issued a Slight Risk of excessive rainfall on Sunday as
convection may organize a bit better with slower cell motions and possible
repeating cells. Given intense rates over dry/hard ground conditions
seeing above normal runoff and spots of flash flooding.
It is that cold front that will usher in fresher, cooler air across the
Northern Plains on Saturday expanding across E Wyoming/Nebraska into
Sunday. High temps only reach the upper 60s and lower 70s or above 5-15
degrees below normal behind the front

The expansion of the heat dome into the Southwest will steadily increase
temperatures into dangerous categories by late Saturday into Sunday. As
such portions of the southeast California and southern Arizona have an
Excessive Heat Warning issued this weekend, where temperatures in the
lower deserts may climb into the 110s.

Gallina

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