266
FXUS01 KWBC 191959
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
358 PM EDT Wed Aug 19 2026

Valid 00Z Thu Aug 20 2026 - 00Z Sat Aug 22 2026

...Heavy rain and flash flooding threats across the Midwest, Ohio
Valley and southern Arizona today, shifting east to the
Mid-Atlantic coast on Thursday...

...Severe storms possible across mid-Mississippi Valley today
through tonight...

... Severe storms possible across Nebraska and flash flooding
possible in the Southeast on Friday...

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

Heavy rain and thunderstorms have developed across much of eastern
Nebraska moving into  southern portions of Iowa and northern
portions of Missouri due to a cold front moving through the
central plains. SPC has a slight risk for severe weather where
these storms are capable of producing  severe wind gusts and hail
as daytime heating maximize. WPC has a slight risk of excessive
rainfall also in the general area. Clusters of organized heavy
showers and thunderstorms will continue traveling eastward across
the central Plains toward the mid-Mississippi Valley this evening
through tonight. These thunderstorms are forecast to become more
focused in the mid-Mississippi Valley through tonight ahead of a
low pressure wave traveling eastward. SPC has a slight risk of
severe thunderstorms across the mid-Mississippi Valley and WPC has
a slight risk of excessive rainfall extending farther north into
the Midwest and Ohio Valley.

Meanwhile, monsoonal showers and thunderstorms will be most active
during the late-day hours across the Four Corners states, where
the WPC has highlighted a marginal risk of Excessive Rainfall
through the next couple of days. In addition, a slight risk is in
place across southern Arizona for today.

By Thursday, the cold front will advance farther eastward and
begin to merge with the meandering front to the south.  A
convergence zone sandwiched between these two fronts will focus a
corridor of enhanced rainfall.  Heavy rain with embedded
thunderstorms is possible along this corridor roughly from I-95
east to the northern Mid-Atlantic coast.  WPC has highlighted this
area for a slight risk of excessive rainfall mainly later on
Thursday when daytime heating is maximized. In addition, SPC has
highlighted a slight risk for severe weather where the main threat
is damaging wind gusts. By Thursday night into early Friday, the
heavy rain should temporarily exit the Mid-Atlantic coast as a
low-pressure wave slides off the coast of southern New England.
Another round of severe weather is possible for eastern Nebraska
into Minnesota and Wisconsin Thursday afternoon into the evening.
A weak low pressure system will migrate from Minnesota into the
U.P. Michigan, creating a weak surface front along with dew points
in the low to mid 60s to generate severe weather. SPC has outlined
a slight risk of severe weather for the area where the main threat
will be large hail, and isolated wind damage.

On Friday, much of central and eastern Nebraska will yet again
experience another round of severe weather. A low pressure system
will develop along a surface trough with ample moisture and strong
instability in place to initiate some supercell thunderstorms. SPC
has highlight a slight risk for severe weather where main threat
will be isolated to scattered damaging hail (some greater than 2
inches),and some severe wind gusts for Friday afternoon into the
evening hours. As for the Southeast, scattered to numerous
thunderstorms are forecast within a very moist and unstable
environment along a surface trough. Single to multi-cell
convection will pose the risk for excessive rainfall where WPC has
highlighted a slight risk for  excessive rainfall from  northern
portions of South Carolina to the southern portions of Virginia.


Temperature-wise, the southern tier of the Lower 48 remains mired
in a steamy air-mass even by mid-to-late August standards. Record
highs and record warm minimum temperatures will be common with the
Southeast at the heart of the anomalous heat through today. The
upper ridge is forecast to strengthen over the Southwest while
cool Canadian air dips further into the Great Lakes. Some cases of
record-breaking warmth are expected in the Desert Southwest and
Southern Plains as temperatures dip into the 40s near the Canadian
border in the upper Midwest. Extreme Heat Warnings are in effect
for much of the Desert Southwest, and Extreme Heat Warnings remain
in effect across portions of the southern Plains to the Deep
South.  Heat Advisories are in effect for all of Florida and the
southeast U.S. coast.  Overnight lows will be so warm (low 80s in
some cases) that, when combined with oppressive dew points,
little-to-no relief from the scorching daytime highs will be
available. Residents are advised to follow proper heat safety tips
by limiting outdoor activity, staying hydrated, ensuring access to
A/C or cooling centers, and checking on vulnerable friends,
neighbors, and family members.


Green/Kong


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




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