Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Mon Aug 22 2022

Valid 12Z Mon Aug 22 2022 - 12Z Wed Aug 24 2022

...Heavy rain impacting northern Texas early today is forecast to shift
toward the lower Mississippi Valley Tuesday and Wednesday...

...Scattered thunderstorms with locally heavy downpours are expected to
move through a large portion of the East Coast over the next couple of
days...

...Heat in the Northwest will spread east into the northern and central
Plains as the heavy rain across the South keeps daytime temperatures
cool...

A multi-day heavy rainfall event is in progress with a general focus
across northern Texas early this morning as an upper-level trough
interacts with a front.  The upper trough will only push the heavy rain
axis relatively slowly east toward the lower Mississippi Valley over the
next couple of days.  Additional rainfall of 3-6 inches with isolated
pockets of 7+ inches are possible over the next 5 days from central Texas
to central Mississippi.  Much of this rainfall will be beneficial and
welcome due to the effects of an ongoing drought, but the potential still
exists for instances of flash flooding in urban areas and places with poor
drainage.  A slight risks of excessive rainfall is forecast for portions
of the southern Plains and lower Mississippi Valley through Tuesday, with
a moderate risk in effect for parts of the ArkLaTex, region into early
this morning where the threat of flash flooding will be the highest.

Elsewhere, an upper-level trough slowly moving eastward across the Ohio
Valley will continue to help trigger rounds of showers and thunderstorms
across much of the East Coast under a warm and moist unstable air mass. 
Some of these storms will contain heavy downpours.  Much of this activity
will spread farther north into New England today as a warm front begins to
lift northward.  The unsettled weather is forecast to persist along the
Eastern Seaboard into early Tuesday before drier air behind the upper
trough pushes the rain out to sea by Tuesday night and into Wednesday
morning.

Temperatures are expected to drop well below average across the southern
Plains and lower Mississippi Valley due to clouds and rainfall forecast
for that region over the next few days.  Meanwhile, the heat will continue
across the Northwest and interior California but with a gradual moderating
trend over the next couple of days.  Some of the heat is forecast to
spread eastward slowly across the northern/central Plains as an area of
low pressure lingers in the lee side of the northern Rockies.  Some
thunderstorms are forecast to be triggered late in the day across the
northern Plains and then taper off later during the night.  Over the
Northeast, above normal temperatures across New England today will give
way to increasing clouds, a chance of heavy rain and cooler temperatures
over southern New England on today as a warm front approaches from the
south.

Kong/Kebede


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