Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Fri Jul 21 2023

Valid 12Z Fri Jul 21 2023 - 12Z Sun Jul 23 2023

...Flash Flooding and Severe Weather threats across parts of the East
Coast, Lower Mississippi Valley and Southern Plains today...

...Lengthy & dangerous heat wave to continue across the Southern tier and
in the West...

...Cooler and more comfortable temperatures spread across Great Plains and
Midwest...


A cold front sweeping through the East Coast and Southeast will be the
focus for thunderstorms over the next couple of days. An upper trough
centered over Hudson Bay will support a surface low pressure system moving
through the interior Northeast today. Thunderstorms (some potentially
severe) and heavy rainfall are forecast for the interior Northeast. An
axis of especially heavy rainfall may develop over portions of eastern New
York/Pennsylvania, New Jersey and Vermont where a Slight Risk of Excessive
Rainfall leading to Flash Flooding is in effect. Rain rates of over an
inch coupled with upslope enhancement are likely to cause runoff issues
over the already saturated Adirondacks and Green Mountains. Elsewhere,
shortwave energy and a cold front will work in tandem to provide
instability, moisture flux and a focus for heavy rainfall along a zonal
axis extending from northeastern Oklahoma to southern Georgia. Slight
Risks of Excessive Rainfall leading to Flash Flooding as well as Severe
Thunderstorms are in effect for the Oklahoma to Georgia corridor where
pockets of over an inch of rainfall, wind damage and hail are expected.
Monsoonal moisture will support additional flash flooding concerns over
Arizona and especially New Mexico today, where another Slight Risk of
Excessive Rainfall leading to Flash Flooding is in effect. Temperatures
are expected to drop off substantially on the backside of the cold front.
High temperatures are likely to be in the 70s and low 80s across the Great
Plains and Midwest through Saturday, which will be 10-25 degrees below
average for this time of year.

A dangerous, long-lived, and record breaking heat wave will continue over
the Southwest through this weekend, particularly in the low desert areas,
with triple digit high temperatures also extending northward into the
Central Great Basin this weekend. Oppressive heat and humidity are
forecast to create widespread 105-110 degree heat indices across the
Mid-South, Southeast and Gulf Coast through early this weekend. Take the
heat seriously and avoid extended time outdoors. Temperatures and heat
indices will reach levels that would pose a health risk, and be
potentially deadly to anyone without effective cooling and/or adequate
hydration. Nighttime temperatures will provide very little relief. Heat is
the leading weather-related killer in the U.S.


Kebede


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