Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
341 AM EDT Fri Aug 11 2023

Valid 12Z Fri Aug 11 2023 - 12Z Sun Aug 13 2023

...Dangerous heat will persist across much of the southern tier of the
U.S...

...Severe thunderstorms possible today for the Midwest and Saturday for
the Ohio Valley/Northeast...

...Monsoonal showers for the Four Corners region with generally below to
near average temperatures in the West...

Dangerous heat will continue for much of the southern tier of the U.S.
into the weekend as a stagnant upper-level high remains in place.
Widespread heat-related advisories and warnings are in effect from Florida
west through the Gulf Coast and into the Lower Mississippi Valley and
Central/Southern Plains, with the most excessive heat expected over
portions of Texas and the Lower Mississippi Valley. Forecast highs Friday
and Saturday range from the mid-90s in Florida and the Central Plains to
the low 100s in Oklahoma and the Lower Mississippi Valley and the mid- to
upper 100s into Texas. When combined with high humidity values, heat
indices will range between 110-120 degrees for many locations. Numerous
record-tying/breaking highs are forecast both days, with similarly
record-level warm low temperatures in the upper 70s to low 80s providing
little relief from the heat overnight. Unfortunately, the heat looks to
continue beyond the current forecast period, with some moderation
potentially by the middle of next week.  Areas north of the Gulf Coast in
the Southeast and into the Carolinas look to be spared some of the most
oppressive heat as a lingering frontal boundary helps to trigger shower
and thunderstorms.

Meanwhile, to the north, energetic upper-level flow above a consolidating
lower pressure system across the Midwest/Plains will provide the focus for
shower and thunderstorm chances Friday. The Storm Prediction Center has
issued a Slight Risk (level 2/5) of severe weather for the Mid- to Upper
Mississippi Valley and Lower Missouri Valley where some of the stronger
storms may produce some instances of damaging winds and large hail.  The
system and subsequent storm chances will shift eastward into the Northeast
and Ohio Valley on Saturday, with another Slight Risk of severe weather in
place for the continued risk of some damaging winds and large hail.
Additional storms are expected to the southwest over portions of the
Central/Southern High Plains as a cold front sags southward across the
region. Another storm system will bring storm chances back to the
Central/Northern Plains into the Midwest Saturday afternoon into early
Sunday. Forecast highs range from the upper 70s to the mid-80s for the
Northeast, the upper 80s to mid-90s for the Mid-Atlantic, the mid 80s to
low 90s for the Midwest, and the low 90s for much of the Plains. The far
northern tier will see cooler temperatures behind a cold front, with 60s
in the Upper Great Lakes and 70s to low 80s in the Northern Plains.

To the West, monsoonal moisture in the Four Corners region will lead to
daily rounds of afternoon thunderstorms with a few locally heavy downpours
possible. This will also help to keep temperatures a bit below average,
with highs only into the upper 70s for some locations. Areas of the
Central/Southern Rockies and Great Basin will be a bit closer to average,
seeing highs in the mid-80s to low 90s, and upper-90s to mid-100s for the
Desert Southwest. A lingering upper-level low will keep temperatures
unseasonably cool over portions of California, as highs are expected to be
in the upper 60s to mid-70s for the coast and mostly 80s for the interior
valleys outside of the Deserts. Conditions will be tranquil with near
average temperatures in the Pacific Northwest. Highs will generally range
from the mid-80s to low 90s. However, an upper-level ridge building in
over the region looks to bring a heat wave just beyond the current
forecast period.

Putnam

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