Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
347 AM EDT Thu Aug 03 2023

Valid 12Z Thu Aug 03 2023 - 12Z Sat Aug 05 2023

...There is a Slight Risk of excessive rainfall over parts of the
Ohio/Tennessee/Middle Mississippi Valleys, Southeast and Southern
Appalachians, along with two areas over the Northern/Central Plains into
the Great Basin...

...There is an Enhanced Risk of severe thunderstorms over parts of the
Central High Plains...

...Excessive Heat Warnings and Advisories from parts of Central/Southern
Plains and the Middle/Lower Mississippi Valley/Central Gulf Coast...

A wave of low pressure over the Central Plains will move eastward into the
Ohio/Tennessee Valleys by Friday. Tropical moisture, upper-level energy,
and a nearby front will create showers and thunderstorms with heavy rain
over parts of the Ohio/Tennessee/Middle Mississippi Valleys, Southeast and
Southern Appalachians. Therefore, the WPC has issued a Slight Risk of
excessive rainfall over parts of the Ohio/Tennessee/Middle Mississippi
Valleys, Southeast and Southern Appalachians through Friday morning. The
associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, and small streams the most vulnerable.

Additionally, the system will produce showers and severe thunderstorms
over parts of Tennessee, Alabama, and northwestern Georgia. Therefore, the
SPC has issued a Slight Risk of severe thunderstorms over parts of the
Tennessee Valley, Southeast, and Southern Appalachians through Friday
morning. The hazards associated with these thunderstorms are frequent
lightning, severe thunderstorm wind gusts, hail, and a few tornadoes.

Meanwhile, upper-level energy and a steady moisture supply will produce
showers and severe thunderstorms over parts of Colorado, northwestern
Kansas, and southwestern Nebraska. Therefore, the SPC has issued an
Enhanced Risk of severe thunderstorms over the Central High Plains through
Friday morning. The hazards associated with these thunderstorms are
frequent lightning, severe thunderstorm wind gusts, hail, and a minimal
threat of tornadoes. However, there is an increased threat of severe
thunderstorm wind gusts of 65 knots or greater over the region.

Moreover, the showers and thunderstorms will create heavy rain over Idaho,
Utah, Wyoming, and South Dakota, as well as an area over parts of eastern
Colorado, southern Nebraska, and northern Kansas. Therefore, through
Friday morning, the WPC has issued a Slight Risk of excessive rainfall
over parts of the Northern Intermountain Region, Great Basin,
Northern/Central Plains, and Northern Rockies, including a second area
over parts of the Central High/Central Plains. The associated heavy rain
will create mainly localized areas of flash flooding, with urban areas,
roads, and small streams the most vulnerable.

Also, on Thursday, a weak front moving southeastward out of Central Canada
will trigger showers and severe thunderstorms over parts of north-central
New York State late in the day. Therefore, the SPC has issued a Slight
Risk of severe thunderstorms over parts of north-central New York State
through Friday morning. The hazards associated with these thunderstorms
are frequent lightning, severe thunderstorm wind gusts, hail, and a few
tornadoes.

The threat of severe thunderstorms continues on Friday over parts of the
Northeast. Therefore, the SPC has issued a Slight Risk of severe
thunderstorms over parts of the Northeast from Friday into Saturday
morning. The hazards associated with these thunderstorms are frequent
lightning, severe thunderstorm wind gusts, hail, and a minimal threat of
tornadoes.

Furthermore, the showers and thunderstorms will create heavy rain over
parts of New England. Therefore, the WPC has issued a Slight Risk of
excessive rainfall over parts of New England from Friday into Saturday
morning. The associated heavy rain will create mainly localized areas of
flash flooding, with urban areas, roads, and small streams the most
vulnerable.

On Friday, upper-level energy and a steady supply of moisture will produce
showers and thunderstorms with heavy rain over parts of southeastern
Montana, northeastern Wyoming, southwestern North Dakota, and the western
half of South Dakota. Therefore, the WPC has issued a Slight Risk of
excessive rainfall over parts of the Northern High/Northern Plains from
Friday through Saturday morning. The associated heavy rain will create
mainly localized areas of flash flooding, with urban areas, roads, and
small streams the most vulnerable. Additionally, showers and moderate to
strong thunderstorms will develop over parts of the Central Plains,
Middle/Lower Mississippi Valley, and the Southeast on Friday.

Furthermore, an upper-level high over the Southern Plains/Lower
Mississippi Valley will create oppressive daytime heat, limited overnight
cooling, which will also contribute to the effects of heat, prompting
Excessive Heat Warnings and Heat Advisories over portions of the
Central/Southern Plains and the Middle/Lower Mississippi Valley/Central
Gulf Coast. Further, a second region of Excessive Heat Warnings and Heat
Advisories are over parts of southeastern California and Southwest.

In addition, an expansive heat wave will continue to affect much of the
country s southern tier through the weekend. The heat will be most
persistent in the south-central U.S., where it may last through the end of
next week with no relief. The combination of heat and humidity in the Gulf
Coast region will result in extremely dangerous peak heat index values
well in excess of 110 F from the weekend into early next week. The
oppressive daytime heat, limited overnight cooling, and widespread
record-warm nighttime lows will pose a significant health risk to anyone
without effective cooling and adequate hydration.

Furthermore, the most persistently elevated heat indices are likely to be
in South and Southeast Texas and southern Louisiana. A few locations could
see a heat index approaching or exceeding 120 F.

Moreover, dangerous heat is also likely to return to the Southwest,
particularly this weekend. The heat may affect the central valley of
California.


Ziegenfelder


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