196
FXUS01 KWBC 170759
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
358 AM EDT Thu Sep 17 2026

Valid 12Z Thu Sep 17 2026 - 12Z Sat Sep 19 2026

...Additional flash flooding expected over sections of the
Southwest, Northern Plains, and Upper Midwest over the next three
days...

...Record-challenging high temperatures continue across the
South-Central U.S....

After a very active day of flash flooding across the Southwest and
Great Basin, the focus for heavy rainfall is expected to shift
towards the Southern Rockies ahead of a moisture-laden disturbance
acting to enhance showers and thunderstorms. While the overall
coverage of storms will be lower than yesterday, any flash
flooding could be similarly impactful as high rainfall rates
continue amid the anomalous moisture in place. The same Southern
Rockies disturbance will eventually trigger the formation of a new
low-pressure system over the central High Plains tonight. As this
system consolidates in the overnight hours, a developing axis of
heavy rainfall along the front will support the threat of widely
scattered flash flooding from the Northern Plains to the Upper
Midwest tomorrow and Saturday.

As we get into mid-September, cooler air from Canada is beginning
to dip into the Northern Tier states, bringing cooler than normal
temperatures behind the aforementioned low-pressure area.
Meanwhile, an upper-level high associated with the persistent heat
dome remains strong across the South, resulting in a pronounced
north-south temperature contrast. High temperatures in the low 70s
and upper 60s can be expected north of the meandering front in the
Central Plains and Midwest, compared to upper 90s and triple-digit
highs south of the front across the Southern Plains and Mid/Lower
Mississippi Valley. Unfortunately, the western end of the front
lifting northward means that the hazardous heat is here to stay
this week across the South. In fact, high temperatures reaching
into the upper 90s to lower 100s will challenge daily records from
the Southern Plains to the lower Mississippi Valley where Heat
Advisories remain in effect. Meanwhile, instability associated
with a stationary front on the southern edge of the heat dome will
continue to bring scattered thunderstorms with heavy downpours
across much of the Sunshine State, although excessive rainfall is
not expected from this activity.

Asherman/Kong


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






$$