Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
317 PM EDT Sat Aug 20 2022

Valid 00Z Sun Aug 21 2022 - 00Z Tue Aug 23 2022

...Heavy Rainfall event to unfold across the Southern Plains and Lower
Mississippi Valley over the next several days...

...Potential Tropical Cyclone Four is forecast to reach southern Texas as
a Tropical Depression on Sunday...

...Above average temperatures in the Northwest and Northeast...

...Scattered to severe thunderstorms possible across the Midwest/Ohio
Valley through Sunday...

A multi-day heavy rainfall event is set to unfold over parts of the
Southern Plains and Lower Mississippi Valley beginning tonight. Shortwave
energy currently driving heavy rain and flash flooding impacts in the
Southwest will move into the Southern Plains tonight, bringing with it a
pool of monsoonal moisture. Additionally, moisture from Potential Tropical
Cyclone Four will surge northward from the Gulf of Mexico and interact
with a surface front draped across the Southern Plains tomorrow. Both
sources of moisture will combine to amplify the heavy rainfall threat over
eastern Texas and the Lower Mississippi Valley Sunday night through
midweek. 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
as a result.

Elsewhere, a slow moving low pressure system will bring showers and
thunderstorms to the Midwest over the next couple of days before spreading
into the East Coast. Thunderstorms tonight may become severe, particularly
over parts of Illinois and Ohio where Slight Risks of Severe Thunderstorms
are in effect. Damaging winds and large hail appear to be the main
concerns from any severe storms that form.

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 Northwest will warm
up beneath a ridge of high pressure on Sunday, before temperatures
moderate a bit early next week. The approaching trough responsible for
potential severe weather in the Midwest will continue to stream warm air
into the Northeast on Sunday before the arrival of showers and
thunderstorms cool things down a bit heading into the work week.

Kebede


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