Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Wed Sep 17 2025

Valid 12Z Wed Sep 17 2025 - 12Z Fri Sep 19 2025

...Coastal low will be slow to exit the Mid-Atlantic and southern New
England...

...Rounds of heavy rain and possible severe thunderstorms across the
northern and central Plains through the next couple of days...

...Tropical moisture from Mario reaching into the Southwest...

...Below average temperatures likely where wet weather occurs next two
days, otherwise above average temperatures expected across much of the
CONUS with heat building across the Midwest...

A coastal storm, reminiscence of a cold-season nor'easter, has made
landfall over the eastern shores of Virginia early this morning.  The
center of the system is forecast to meander near the Mid-Atlantic coast
today while steadily weakens over land.  Bands of rain and a few embedded
thunderstorms are forecast to gradually become more scattered across the
Mid-Atlantic states today, with some of the heavy rain possibly reaching
southeastern New England.  By Thursday, the remnant circulation of the
system will be slowly sliding off the Mid-Atlantic coast with sunshine
returning during the day.  A cold front dipping from eastern Canada will
begin to trigger showers across northern New England early on Friday.

Meanwhile, another upper-low will be in a slow process to roll across the
Intermountain West into the mid-section of the country.  The slow
evolution of this system will bring a couple of days of unsettled weather
across the northern and central Plains in the form of locally heavy rain
and strong to severe thunderstorms.  The severe storm and heavy rain
potentials are expected to be greatest early today across the
north-central Plains and will shift toward the south-central High Plains
later today. As a low pressure system gradually consolidates over the
northern and central Plains, a swath of 1-2 inches of rain can be expected
across western South Dakota through tonight on the back side of the
system.  From Thursday into early Friday, the heavy rain and severe storm
potentials will be lowered.  Nevertheless, a good chance of showers and
thunderstorms is expected across the northern Plains and extend as far
south as Oklahoma.

Tropical moisture associated with Mario, which has become post tropical
off the west coast of the Baja, is forecast to bring scattered showers
into far southern coastal California and the offshore islands today, with
these showers pushing farther north into much of southern California on
Thursday. Overall, any rainfall amount across the Southwest and central
Rockies will be beneficial, as these areas have been notably dry. A
general half an inch of rain can be expected to gradually work its way up
the southern half of California through Friday morning with higher amounts
across wind-facing terrains. Some of the rain will also work its way into
southern Arizona and southern New Mexico. 

Temperatures across much of CONUS for the next few days will be above
normal, with the upper and middle Mississippi Valley seeing 10-15 degrees
above normal. Heat is expected to increase across the Midwest with the
passage of a warm front where high temperatures well into the 90s are in
the forecast.  Meanwhile, the East Coast as well as the northern Rockies
into the northern and central High Plains will see below normal
temperatures.

Kong


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