Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
355 PM EDT Thu Sep 23 2021

Valid 00Z Fri Sep 24 2021 - 00Z Sun Sep 26 2021

...There is a Slight Risk of excessive rainfall over parts of the
Northeast/northern Mid-Atlantic through Friday morning...

...Temperatures will be 10 to 20 degrees above average over parts of the
Northeast through Saturday...

A front extending from the Lower Great Lakes to the Mid-Atlantic Coast
will move very slowly, almost stationary moving to Northeast Coast by
Saturday.  Moisture streaming off the Atlantic will pool along the
boundary through Friday morning when the moisture flow weakens slightly. 
Showers and thunderstorms will develop along ahead of the front through
Saturday morning.  Some of the storms will produce heavy rain.  Therefore,
the WPC has issued a Slight Risk of excessive rainfall with these
thunderstorms over parts of the Northeast/northern Mid-Atlantic through
Friday morning.  The associated heavy rain will create mainly localized
areas of flash flooding, with urban areas, roads, and small streams the
most vulnerable.  The excessive rainfall threat weakens slightly on Friday
and continues over parts of the Northeast through Saturday.

Furthermore, upper-level ridging and warm moist air flowing into the
Northeast will allow temperatures to be 10 to 20 degrees above average
over parts of the Northeast through Saturday when the front moves to the
coast.  In addition, the trailing front will linger over parts of the
Florida Peninsula through Saturday, aiding in the development of showers
and thunderstorms over the region.

Meanwhile, another front over the Upper Midwest to the Great Basin will
move into the Great Lakes overnight Friday and into the Lower Great Lakes
by Saturday.  On Friday, showers and thunderstorms will develop along and
ahead of the boundary over parts of the Upper Mississippi Valley/Upper
Great Lakes, moving into the Great Lakes/Ohio Valley on Saturday.

Elsewhere, upper-level energy and moisture over the Southwest will aid in
producing widely scattered showers and thunderstorms over the area through
Saturday. Additionally, upper-level ridging just off the West Coast and
weak high pressure at the surface will create light wind over the San
Joaquin Valley provide stagnant airflow. Therefore, Air Quality alerts are
over parts of California due to smoke from wildfires.

Ziegenfelder

Graphics are available at www.wpc.ncep.noaa.gov/basicwx/basicwx ndfd.php