Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Mon Aug 25 2025

Valid 00Z Tue Aug 26 2025 - 00Z Thu Aug 28 2025

...Scattered showers and locally heavy thunderstorms are expected across
portions of the Southwest through Tuesday...

...Rounds of heavy rain and thunderstorms are anticipated across portions
of Colorado, Kansas, Oklahoma, and Arkansas through Wednesday...

...The Pacific Northwest will remain hot into Tuesday as cool conditions
overspread the central and eastern U.S....

...Showers and thunderstorms are expected to become more numerous across
the northern Great Basin to the northern/central Rockies late Tuesday into
Wednesday...

Through Wednesday, monsoonal moisture, diurnal heating, and upper-level
impulses will produce showers and thunderstorms over portions of the West.
 Slight Risks of excessive rainfall/flash flooding exist across portions
of the Southwest on Tuesday and Idaho/southwest Montana on Wednesday. 
Elevated convection with heavy rainfall north of a front will develop at
times over parts of Colorado, Oklahoma, Kansas, and Arkansas through
Wednesday with a Slight Risk of excessive rainfall depicted over portions
of these areas.  Hourly amounts as much as 2.5" would be problematic in
urban areas.  Swaths of heavy rain each day are expected to increase soil
saturation over time, making areas increasingly sensitive to further heavy
rainfall.  For the West, the main concern is flooding of dry
washes/arroyos, urban areas, burn scars, and box canyons due to scattered
showers and locally heavy thunderstorms that are most active late
afternoon into the early evening hours.  From late Tuesday into Wednesday,
showers and thunderstorms are expected to develop and become more numerous
across the northern Great Basin to the northern/central Rockies due to the
arrival of a slow-moving upper trough.

Meanwhile, warm core ridging across the Northwest will aid and abet a heat
wave across Northwest continuing into Tuesday before losing its grip on
Wednesday.  Daily record highs will once again be challenged Tuesday
afternoon as temperatures soar to near 100F at the hottest locations. 
This heat will be dangerous, posing a threat to anyone without effective
cooling and adequate hydration.  In addition, there will be little
nighttime relief from the extreme heat, with overnight lows remaining well
above normal.  Extreme heat is dangerous even at night when temperatures
do not cool down.  Stay informed and take steps to protect yourself from
heat-related illnesses.  For information on staying cool and safe, visit
www.weather.gov/safety/heat. As temperatures rise, limit outdoor activity,
stay hydrated, and ensure access to air-conditioning and other cooling
areas.

Meanwhile, east of the Rockies and north of the Gulf Coast, large swaths
of below average temperatures are expected to prevail, with temperatures
more reminiscent of early fall than late summer under the aegis of strong
high pressure (by August standards).  Cool to cold conditions are expected
overnight from the Gulf Coast northward, with resplendent sunshine during
the day over portions of the Midwest, Appalachians, and much of the East. 
In fact, temperatures dipping into the 40s and 50s across the east-central
U.S. will threaten low temperature records from across the Midwest to the
Ohio and Tennessee Valleys, as well as the Mid-South for the next couple
of mornings at least.  In areas with rain, such as Kansas/Oklahoma, the
ArkLaTex and Red River Valley of the South on Tuesday, and into Kansas on
Wednesday, highs may only reach into the 60s and 70s threatening record
cold maxima for the dates.  Across the Great Lakes, the arrival of an
upper-level trough axis will even add instability to the cool air mass,
triggering lake-effect and lake-enhanced showers and a few thunderstorms
in the vicinity through Tuesday.  By Wednesday, these instability showers
and embedded thunderstorms will be triggered farther east across upstate
New York into interior New England where the upper trough is forecast to
move through.  Meanwhile, showers and some thunderstorms ahead of a cold
front dipping south across southern Canada are expected to develop over
the upper Great Lakes by Wednesday afternoon.

Kong/Roth


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