451 
FXUS01 KWBC 171957
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
357 PM EDT Fri Jul 17 2026

Valid 00Z Sat Jul 18 2026 - 00Z Mon Jul 20 2026

...Heavy rainfall threat continues in the Texas Big Bend today;
dangerous flash flooding remains possible...

...Daily monsoonal showers and thunderstorms continue across the
Western U.S. this weekend; stormy weather expected over parts of
the Northern Tier and Mid-Atlantic

...Air quality alerts span from the Upper Midwest Great Lakes to
New England...

...Heat and humidity persists across the Northern Plains/Upper
Midwest; lingers in the Mid-Atlantic through tomorrow...

A slow-moving weather regime continues across the Southern Tier
states as an upper-level low near the Texas Big Bend slowly
retrogrades towards the Desert Southwest. This upper-level low
(one key ingredient in the catastrophic Texas flash flooding) is
forecast to meander northwestward today, which will lessen the
coverage of showers and thunderstorms in central Texas this
weekend. The slow nature of this feature unfortunately means that
scattered pockets of very heavy rain remain possible near the
Texas Big Bend, which would exacerbate the dangerous flooding from
the last few days of extreme rainfall.

Monsoonal thunderstorms capable of isolated to scattered severe
weather flash flooding are forecast to track from north to south
across the Four Corners region through tomorrow under the
influence of the aforementioned southern High Plains upper-low.
Along the Northern Tier, a transitory frontal system will also
drive daily showers and thunderstorms this weekend, some of which
could produce scattered severe weather from the Ohio Valley into
the Mid-Atlantic tomorrow. 

Hot and humid conditions expected to persist across the Great Lake
and Northern Plains for several days with daily highs in the 90s
to lower 100s expected. Smoke continues to disperse from the
Minnesota and Canadian wildfires downstream into the Northeast and
Mid-Atlantic regions resulting in poor Air quality. Meanwhile,
another day of triple-digit high temperatures and elevated
humidity is expected for the northern Mid-Atlantic today before
temperatures moderate with the frontal passage this weekend. 

Asherman/Campbell


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




$$