Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
1207 AM EDT Thu Jul 07 2022

Valid 12Z Thu Jul 07 2022 - 12Z Sat Jul 09 2022

...Widespread showers and thunderstorms with excessive rainfall and severe
weather possible through Friday from the High Plains to the East Coast...

...Dangerous heat and humidity to continue from parts of the
Central/Southern Plains to the Mid-Atlantic and Southeast...

Weather highlights and hazards for the short-term forecast period will be
largely dominated by a persistent upper-level ridge over the central U.S.
and a quasi-stationary frontal boundary draped from the High Plains to the
Mid-Atlantic. Upper-level disturbances moving southeastward along the
ridge as well as high surface moisture (low to mid-70s dewpoints) along
the frontal boundary will help to trigger widespread showers and
thunderstorms both today and Friday, with multiple areas under the risk of
excessive rainfall and severe thunderstorms each day. Today, there are
Slight Risks of excessive rainfall (level 2/4) for the coastal Carolinas,
the Middle-Mississippi/Ohio Valleys, and the Northern Plains. Slight Risks
are also again in effect for the Middle-Mississippi/Ohio Valleys and the
southern Appalachians as well as the coastal Carolinas on Friday. The
combination of greater areal coverage of rainfall from organized
convective complexes, high moisture content leading to efficient rainfall
rates, and proceeding days of heavy rainfall leading to more saturated
soils will lead to the risk for isolated to scattered instances of flash
flooding. The Storm Prediction Center has also issued Slight Risk outlook
areas for severe thunderstorms (level 2/5) from the Tennessee Valley to
the Carolinas as well as the Northern Rockies and High Plains today. Some
thunderstorms may produce damaging winds, and large hail will also be a
threat in the Northern Rockies and High Plains. A Slight Risk is also in
effect for the Northern Rockies and High Plains on Friday for the
continued risk of scattered instances of damaging winds and large hail.
Thunderstorms in this region may also have the tendency to grow upscale
into organized convective lines in the evening hours, enhancing the threat
for damaging winds.

Meanwhile, a dangerous heat wave continues south of the frontal boundary
over the Central/Southern Plains to the southern Mid-Atlantic and
Southeast. High temperatures are forecast to be in the low 100s for most
of the Central/Southern Plains and east into the Mid-South and Tennessee
Valley today. Mid-to-upper 90s are expected elsewhere from the Ohio Valley
to the Mid-Atlantic and Southeast. These already hot temperatures will be
made even more uncomfortable when combined with the high humidity in place
across the region. Excessive Heat Warnings are in effect today for areas
from Kansas City east to St Louis and Louisville and south to Memphis as
heat indices will soar into the 110-115 degree range. Widespread Heat
Advisories are also in effect for the region through Friday for still very
uncomfortable heat indices in the 105-110 degree range. Just as
concerning, low temperatures will remain very warm overnight providing
little relief from the sweltering conditions during the day. Near
record-tying/breaking forecast lows from the mid-70s to low-80s are
expected. Excessive heat is especially dangerous for vulnerable
populations. Be sure to check in on friends and loved ones frequently.

Elsewhere, to the northeast of the ridge, temperatures will remain cooler
than normal for New England, with highs in the 70s along the coast and the
low 80s inland. An upper-level trough over the Pacific Northwest will also
keep temperatures cooler than normal for early July, with mostly 70s and
low 80s expected. However, conditions should remain mostly dry. High
temperatures for California and the Great Basin will tend to be around or
a bit cooler than normal, with 60s-70s along the immediate coast, 80s to
90s in the interior valleys, and 100s for the Desert Southwest. Elevated
fire weather concerns continue over the Great Basin through Friday.

Putnam/Kebede

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