Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Wed Sep 08 2021

Valid 12Z Wed Sep 08 2021 - 12Z Fri Sep 10 2021

...Severe thunderstorms and heavy rain possible today from the northern
Mid-Atlantic to western New England...

...A heat wave in the western U.S. will gradually shift eastward into the
central/southern High Plains by Friday...

...Watching for the potential of tropical cyclone development near the
eastern Gulf Coast to the Southeast U.S. coast the next couple of days...

A cold front extending southwestward from a low pressure system in
east-central Canada will move through the Great Lakes and into the
Appalachians today.  Showers and thunderstorms will be most active ahead
of the cold front.  In fact, thunderstorms could become severe later today
as they become organized across the northern Mid-Atlantic to western New
England, where a low pressure wave is forecast to form along the front. 
In addition, heavy downpours can be expected with these thunderstorms. 
The associated heavy rain will increase the threat of localized areas of
flash flooding, with urban areas, roads, and small streams the most
vulnerable from Wednesday through Thursday morning, especially over areas
recently impacted by the severe flooding due to Ida.  The front will make
a slow but steady eastward progress across New England on Thursday and
should exit Maine by Friday morning.  A decreasing threat of heavy rain
and severe thunderstorms will spread into New England on Thursday before
the rain moving off the coast by Friday morning.

Meanwhile, an upper-level high over the Great Basin will aid in producing
record high temperatures over the western states through Thursday.  The
persistent dry weather under the upper-level high together with gusty
winds will continue to raise the fire weather threat and poor air quality
from the Pacific Northwest to the northern Rockies and into the central
High Plains.  Excessive Heat Warnings remain in effect over the Mojave
Desert while Heat Advisories are also posted over most of the interior
valleys of California.  Record high temperatures can be expected each
afternoon at many locations, shifting into the central High Plains by
Friday.

Showers and thunderstorms will continue over parts of the Southeast.  Also
watching for the potential of tropical cyclone development near the
eastern Gulf Coast to the Southeast U.S. coast the next couple of days.

Kong


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