Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Tue Jul 21 2026

Valid 12Z Tue Jul 21 2026 - 12Z Thu Jul 23 2026

...Strong frontal system to produce widely scattered severe weather and
flash flooding from the Mid-South into the Northeast...

...T.D. Two to bring heavy rain threats across the Gulf Coast...

...Monsoonal thunderstorms to continue over the next few days from the
Southwest into the Great Basin...

...Hazardous heat builds across the Southern Plains and Southeast...

An unseasonably deep low pressure system continues a steady advance across
the Upper Great Lakes this morning. Over the next 48 hours, a well defined
cold front protruding from this low center is expected to press
southeastward, which will set the stage for active severe weather and
flash flooding from the Mid-South into the Northeast as a moist and
unstable airmass pools ahead of the front. Severe wind gusts and flash
flooding are expected to be the main hazards from any thunderstorms this
afternoon, although severe hail and a few tornadoes are also possible. By
tomorrow, another round of flash flooding and severe weather is possible
over portions of the lower Mid-Atlantic as the frontal boundary migrates
eastward. Meanwhile, across the northeast Gulf, Tropical Storm Bertha is
expected to continue a westward track just south of the Florida Panhandle
towards Southeast Louisiana. Much of the rainfall with this system is
still expected to remain south of the coastline, although the outer bands
of Bertha could still support isolated to scattered flash flooding over
the next two days. See the latest NHC advisories for additional and
updated information on this storm. 

Over into the southwest, monsoonal moisture circulating around the western
periphery of the ridge will continue to support scattered afternoon and
evening thunderstorms across the central and southern Rockies. Storm
motions will generally remain slow, producing locally heavy rainfall,
especially over higher terrain through Wednesday.

Temperature wise, a subtropical ridge will maintain anomalous heat across
the Southeast and southern Plains, where 105-115 degree heat indices can
be expected. With the addition of little overnight recovery, as lows are
expected to drop to 75-80 F, heat related illness will be of concern over
the next few days, especially for those without adequate cooling or
hydration. Further north, below normal temperatures will build behind the
cold front, across the Upper Midwest/Great Lakes into the Northeast.

Asherman/Oudit

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