Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
325 PM EDT Tue Sep 02 2025

Valid 00Z Wed Sep 03 2025 - 00Z Fri Sep 05 2025

...There is a Slight Risk of excessive rainfall over parts of southern
California and southwestern Arizona on Tuesday and Wednesday...

...There is a Slight Risk of severe thunderstorms over parts of the
Central Plains and Middle Mississippi Valley on Wednesday...

...There are Extreme Heat Warnings and Heat Advisories over the interior
Northwest...

A weak front extending from the Tennessee Valley southwestward to the
Southern Plains will dissipate by Wednesday.  Moisture pooling along the
front will aid in producing showers and thunderstorms over parts of the
Tennessee Valley through Wednesday afternoon.

Moreover, monsoonal moisture, diurnal heating, and upper-level impulses
will produce showers and thunderstorms over Central/Southern California,
the Southwest, and the Great Basin through Thursday. Heavy rain is
expected to develop over parts of southern California and southwestern
Arizona. Therefore, the WPC has issued a Slight Risk (level 2/4) of
excessive rainfall over southern California and southwestern Arizona
through Wednesday morning.  The associated heavy rain will primarily
create localized areas of flash flooding, with urban areas, roads, small
streams, and low-lying areas being the most vulnerable.

In addition, showers and thunderstorms with heavy rain will develop over
southern California and southwestern Arizona on Wednesday into Thursday.
Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive
rainfall over southern California and southwestern Arizona from Wednesday
through Thursday morning.  The associated heavy rain will primarily create
localized areas of flash flooding, with urban areas, roads, small streams,
and low-lying areas being the most vulnerable.

Meanwhile, a front extending from the Upper Mississippi Valley across the
Northern Rockies and into the Northern High Plains will move south and
eastward to the Lower Great Lakes/Central Appalachians into the Ohio
Valley by Thursday. The system will produce showers and thunderstorms over
the Upper Mississippi Valley on Tuesday evening, moving across the Great
Lakes on Wednesday, and into the Lower Great Lakes/Northeast to the
Central Appalachians and Mid-Atlantic on Thursday.

Along the southern edge of the front, showers and severe thunderstorms
will develop over parts of the Central Plains/Middle Mississippi Valley.
Therefore, the SPC has issued a Slight Risk (level 2/5) of severe
thunderstorms over parts of the Central Plains/Middle Mississippi Valley
from Wednesday through Thursday morning.  The hazards associated with
these thunderstorms are frequent lightning, severe thunderstorm wind
gusts, hail, and a minimal threat of tornadoes. Additionally, there is an
increased threat of hail, two inches or greater, over parts of the region.

A second front will move southward out of West-Central Canada overnight
Wednesday, moving into the Upper Mississippi Valley by Thursday evening.
The system will produce showers and thunderstorms over parts of the
Northern Plains by Thursday morning and into the Upper/Middle Mississippi
Valley by Thursday evening. Furthermore, a third front will linger over
Florida through Thursday. Tropical moisture and the front will aid in
producing showers and thunderstorms over Florida, also through Thursday.

Lastly, an upper-level ridge over the Northwest will allow temperatures to
rise into the nineties and the triple digits through Thursday. The NWS has
issued Extreme Heat Warnings and Heat Advisories over the interior
Northwest.


Ziegenfelder


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