Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
1251 AM EDT Fri Sep 18 2026

Valid 12Z Fri Sep 18 2026 - 12Z Sun Sep 20 2026

...Heavy rain and flash flooding concerns over north-central U.S. through
the weekend...

...Potential record breaking high temperatures continue across the
South-Central U.S. through the weekend...


A progressive upper-level low over the Pacific Northwest will move
eastward across the northern tier, bringing active weather across the
northern Rockies into the Great Lakes into the weekend. The disturbance
will help push the frontal boundary into the Rockies/Plains by Friday,
which will provide the primary forcing for showers and thunderstorms. A
deep plume of warm moisture will accompany the system, while instability
continues to increase ahead of the disturbance. This setup may produce
repeated convection, which will lead to heavy rainfall and flash flooding
concerns across the Rockies/Plains eastward into the Upper Mississippi
Valley and Midwest. On Saturday, the system continues to progress eastward
into the Great Lakes, while a moist and unstable airmass remains in place
ahead of the system. This will shift the heavy rainfall/flash flooding
potential into portions of the Midwest, Ohio Valley, and lower Great Lakes
through Saturday. Gradually the system moves towards the
Northeast/Mid-Atlantic by late Saturday/early Sunday.

Meanwhile, a portion of the frontal system will drape southward across
portions of the Mid-Atlantic/Southeast, bringing showers and thunderstorms
along the boundary. The combination of deep tropical moisture and slow
moving systems, high rainfall rates may lead to excessive rainfall across
portions of Florida through Saturday. Across the Southwest and Four
Corners, monsoonal activity will gradually decrease and shift slightly
east by Saturday but residual moisture will continue to produce isolated
afternoon and evening thunderstorms, particularly over higher terrain.

In contrast to an active northern tier, ridging over the southern Plains
and Southeast will maintain hot and humid conditions across much of the
south-central U.S. Temperatures will remain well above seasonal with highs
in the 90s to low 100s, with some locations potentially approaching or
exceeding daily record values. With overnight lows remaining well in the
70s, recovery will be minimum. Therefore, widespread Moderate to Extreme
HeatRisk will be forecasted through the weekend. Otherwise, near or
slightly below average temperatures will build across much of Western U.S.
and along the frontal boundary across the northern tier.



Oudit


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

--- MBSE BBS v1.1.7.2 (Linux-x86_64)
 * Origin: Outpost BBS * Johnson City, TN (618:618/1)