Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
403 PM EDT Sat Jul 15 2023

Valid 00Z Sun Jul 16 2023 - 00Z Tue Jul 18 2023

...There is a Moderate Risk of excessive rainfall over parts of New
England on Sunday...

...There is a Slight Risk of severe thunderstorms over parts of the
Southern High Plains...

...Excessive Heat Warnings and Advisories from the Pacific Northwest,
California,  and the Great Basin to parts of the Southern Plains, Central
Gulf Coast, and southern tip of Florida...

...Air Quality alerts over parts of the Northern High Plains, Upper
Midwest, and Ohio Valley...

A weak front over the Ohio Valley southwestward to the Southern High
Plains will slowly move eastward to the East Coast by Monday. The boundary
will create showers and thunderstorms with heavy. Therefore, the WPC has
issued a Slight Risk of excessive rainfall over parts of the Ohio
Valley/Central Appalachians and a second area over the Southern High
Plains through Sunday morning. The associated heavy rain will create
mainly localized areas of flash flooding, with urban areas, roads, and
small streams the most vulnerable.

Furthermore, a stream of tropical moisture flowing from the Central Gulf
Coast to the northern Mid-Atlantic will also produce showers and
thunderstorms with heavy rain. Therefore, the WPC has issued a Slight Risk
of excessive rainfall over parts of the Central Gulf Coast and a second
area over the northern Mid-Atlantic/Northeast through Sunday morning. The
associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, and small streams the most vulnerable.

Moreover, along the western portion of the front, as mentioned earlier,
showers and severe thunderstorms will develop over parts of northeastern
New Mexico and the Texas Panhandle. Therefore, the SPC has issued a Slight
Risk of severe thunderstorms over parts of the Northeast and Mid-Atlantic
through Sunday morning.

The hazards associated with these thunderstorms are frequent lightning,
severe thunderstorm wind gusts, hail, and a few tornadoes.

In addition, there is an increased risk of severe thunderstorm wind gusts
of 65 knots or greater and hail two inches or greater over northeastern
New Mexico.

On Sunday, the front moving into the Mid-Atlantic will extend northward
into New England with a plume of tropical moisture extending from the
Central/Eastern Gulf Coast over the Mid-Atlantic coast into New England,
creating showers and thunderstorms with heavy rain. Therefore, the WPC has
issued a Moderate Risk of excessive rainfall over parts of New England
from Sunday into Monday morning. The associated heavy rain will create
numerous areas of flash flooding. Furthermore, many streams may flood,
potentially affecting larger rivers.

Additionally, a wave of low pressure along a second front extending from
the Great Lakes southwestward to the Central Plains/Middle Mississippi
Valley will create showers and severe thunderstorms over parts of Kansas
and northwestern Missouri. Therefore, the SPC has issued a Slight Risk of
severe thunderstorms over parts of the Central Plains and Middle
Mississippi Valley from Sunday into Monday morning. The hazards associated
with these thunderstorms are frequent lightning, severe thunderstorm wind
gusts, hail, and a minimal threat of tornadoes. The threat of severe
thunderstorms decreases slightly on Monday. Therefore, the SPC has issued
a Marginal Risk of severe thunderstorms over parts of the Northern/Central
Plains and Lower Missouri Valley. The hazards associated with these
thunderstorms are frequent lightning, severe thunderstorm wind gusts, and
a threat of tornadoes and hail.

Meanwhile, upper-level high over California/Great Basin eastward to Texas
will extend upper-level ridging into parts of the Pacific Northwest,
bringing hot high temperatures and low temperatures not cooling off much
overnight, which have contributed to Excessive Heat Warnings and Heat
Advisories over California, Nevada, Arizona, southern New Mexico, and
Louisiana and parts of Texas, Arkansas, Mississippi, Alabama, and the
southern tip of Florida.

In addition, the ridge will bring an extremely dangerous heat wave over
the Southwest into the weekend and likely peak in intensity on Sunday for
much of the region. Dangerous heat may continue into next week for parts
of the region. All-time heat records could be approached or reached at
some locations in the Southwest. The all-time heat records would likely be
on Sunday, particularly in the San Joaquin Valley, Mojave Desert, and
Great Basin regions. Phoenix is also likely to register its hottest week
on record by 7-day average temperature. Take the heat seriously and avoid
time outdoors. Temperatures will reach levels that pose a health risk and
are potentially deadly to anyone without effective cooling and/or adequate
hydration. Heat is the leading weather-related killer in the U.S..

Lastly, wildfire smoke from Western Canada will reduce air quality over
parts of the Northern High Plains, Upper Mississippi Valley, Great Lakes,
and Western Ohio Valley, prompting Air Quality Warnings over the area.


Ziegenfelder


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