827
FXUS01 KWBC 180722
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
321 AM EDT Sat Jul 18 2026

Valid 12Z Sat Jul 18 2026 - 12Z Mon Jul 20 2026

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

...Air quality alerts span from the Upper Midwest Great Lakes to
New England; some relief in sight...

...Hot weather to build over the Central U.S. this week...

This weekend features a fairly active weather pattern along the
Northern Tier of the Nation as an amplifying trough begins to
pivot across the Upper Great Lakes, in turn sending a frontal
system through the Northeast and Ohio Valley today. A moist and
unstable airmass surging northward ahead of this system will set
the stage for showers and thunderstorms capable of widely
scattered severe weather and flash flooding later this morning and
afternoon across these regions. By tomorrow, the front is expected
to sink southward into the lower Mid-Atlantic, which will focus
thunderstorms near the Carolinas. South of this activity, the
eastern Gulf Coast can also expect unsettled weather as a
disturbance south of the Florida Panhandle gradually develops over
the next 24-36 hours. The National Hurricane Center shows a low
chance of tropical cyclone potential with this disturbance,
although isolated instances of flash flooding from this feature
are possible near the Florida Panhandle today and tomorrow. In
contrast to the Northern Tier, a slow-moving weather regime
continues across the Southern Tier states where a persistent
upper-level low in west Texas is slowly retrograding towards the
Desert Southwest. This feature could enhance monsoonal
thunderstorms over the Four Corners and Desert Southwest today and
tomorrow, leading to widely scattered flash flooding as soils are
sensitive from recent precipitation.

Rainfall aside, the approaching frontal system should
simultaneously scour out smoke in the Northeast and Mid-Atlantic
while ushering in cooler air from the north. Unfortunately,
upstream areas in the Midwest and Upper Great Lakes will likely
contend with poor air quality at least through tomorrow as
northwesterly flow ushers in another smoke plume from Ontario. Hot
and humid conditions are expected to spread from the Northern
Plains into the Lower Mississippi Valley beneath a broad
upper-ridge to close out the weekend. In advance of the heat,
scattered Heat Advisories are noted across the Central U.S. where
heat index readings could exceed 110 degrees in some locations.

Asherman

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




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