676
FXUS01 KWBC 210638
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
233 AM EDT Fri Aug 21 2026

Valid 12Z Fri Aug 21 2026 - 12Z Sun Aug 23 2026

...Severe weather and flash flood threats across parts of the East
through Saturday, with severe/flooding threats across portions of
Central Plains on Friday...

...Dangerous heat persists in the South while building into the
Southwest through the weekend...


Unsettled weather continues into the weekend as a broad
upper-level ridge remains entrenched across the southern U.S.,
while several shortwave disturbances and surface boundaries move
through central and eastern U.S. The frontal boundary draping
across the Southern Plains to the Southeast and northward into the
Mid-Atlantic will continue to interact with unstable and warm
airmass. This will support multiple rounds of showers and
thunderstorms, leading to possible Slight Risk for excessive
rainfall and flash flooding, especially across Virginia into the
Carolinas. Additionally, Storm Prediction Center has highlighted a
Slight Risk for severe thunderstorms, capable of producing
severe/damaging wind gust on Friday across the
Southeast/Carolinas. The boundary will continue to lift northward
and slowly move eastward on Saturday, while a second boundary
follows behind. This will bringing additional rainfall across the
eastern seaboard, leading to clustered thunderstorms that may
produce excessive rainfall/flash flooding, especially across the
East Coast, while the Lower Great Lakes/Ohio Valley may experience
severe thunderstorms.

Across central U.S., another frontal boundary will bring chances
for showers and thunderstorms as the boundary moves southward and
interacts with increasing instability and deep-layer shear.
Organized convection may develop, which may lead to Slight Risk
for severe thunderstorms, hail, and damaging winds across the
central Plains and Midwest, while a Marginal Risk is in place for
excessive rainfall/heavy rainfall across portions of the central
Plains, that may lead to localized flooding through Saturday
morning. Across the southwest, monsoonal moisture will remain
concentrated across the Four Corners and southern Rockies.
Afternoon heating combined with terrain-driven circulations will
initiate scattered thunderstorms through the weekend, with locally
heavy rainfall possible from slow-moving storms. On Saturday, the
ridge will shift eastward, while a shortwave disturbance pushes
into the Pacific Northwest. The influx of moisture will expand the
flooding threat northward, covering much of western U.S., as
storms are expected to develop along the boundary. Additionally,
the storm may produce severe thunderstorms and a chance for small
hail within the stronger cells.

Meanwhile, dangerous heat continues across the south-central U.S.
and the Southwest through the weekend as the ridge continues to
support above normal temperatures. Numerous daily record highs are
expected, with daytime highs of 100-110 degrees across the
Southern Plains into the Southwest. With little to no overnight
relief, as minimum temperatures will remain warm, and high
humidity, heat indices may reach 105-115 degrees. Therefore,
expect widespread Major to Extreme HeatRisk through the weekend.
Refer to Key Messages issued by WPC for additional information on
this event.


Oudit


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




$$