Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
401 AM EDT Sun Aug 21 2022

Valid 12Z Sun Aug 21 2022 - 12Z Tue Aug 23 2022

...Heavy rainfall event unfolding across the southern Plains to the lower
Mississippi Valley over the next several days...

...Rounds of strong thunderstorms expected to move across the Ohio Valley
toward the Appalachians today...

...Heat in the Northwest will spread east into the northern Plains as
unsettled weather moves into the East Coast...

A multi-day heavy rainfall event is in progress over parts of the southern
Plains as an upper-level trough begins to direct the antecedent heavy rain
across the Southwest eastward. Meanwhile, the trough interacts with a
front settling in from the north.  An axis of heavy rainfall is forecast
to set up across northern Texas today.  This heavy rain axis will only
progress relatively slowly east toward the lower Mississippi Valley over
the next couple of days. Between 4-8 inches of rain with isolated pockets
of 10+ inches are forecast to accumulate over the next 5 days from central
Texas to eastern Louisiana. 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. Slight Risks of Excessive Rainfall leading to Flash Flooding are
in effect for portions of the southern Plains and lower Mississippi
Valley, with a moderate risk over northeast Texas and nearby Oklahoma
today.

Elsewhere, an upper-level low slowly moving eastward across the Midwest
will continue to bring rounds of showers and thunderstorms, some of which
will be strong with heavy downpours, across the Ohio Valley and into the
Appalachians today.  Much of these activities will spread into the eastern
U.S. on Monday as a front begins to lift northward up the East Coast.  The
unsettled weather is forecast to persist into early on Tuesday as the
upper low continues to take its time moving across the Northeast.

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 few days.  Some of the heat is forecast to spread
eastward slowly across the northern Plains as a low pressure system
lingers in the lee side of the northern Rockies.  Over the Northeast,
above normal temperatures across New England today will give way to
increasing clouds with a chance of heavy rain over southern Ne England on
Monday as a warm front approaches from the south.

Kong/Kebede


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