Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
403 AM EDT Wed Jul 20 2022

Valid 12Z Wed Jul 20 2022 - 12Z Fri Jul 22 2022

...Dangerous heat to continue through midweek across the south-central
U.S., building into the Northeast today...

...Severe thunderstorms possible across portions of the Great Lakes and
Ohio Valley today, and the Northeast and Southeast on Thursday...

...Monsoonal moisture to bring locally heavy rains and isolated flash
flooding across portions of the Southwest into the southern Rockies...

A large portion of the U.S. population remains under heat-related warnings
and advisories.  Approximately 100 million people are currently under an
Excessive Heat Warning or Heat Advisory.  This includes a large portion of
the southern Plains, the lower Mississippi Valley, the lower Ohio Valley,
and parts of the Tennessee Valley.  Above-normal temperatures are expected
across the region, reaching the triple digits in many locations.  High
temperatures are forecast to break several more daily records across
Texas, Louisiana, and Arkansas today.  Temperatures are expected to be a
few degrees cooler as a cold front drops into the Arkansas Basin and lower
Mississippi Valley, with a chance for showers and thunderstorms on
Thursday. But overall, temperatures will likely remain above normal across
most of the region for the next several days.

Farther to the northeast, a cold front will continue to push across the
Great Lakes and Ohio Valley today.  This will be bring showers and
thunderstorms into the region.  Some of these storms may become strong to
severe, especially across portions of lower Michigan into the Ohio Valley,
producing damaging winds, as well as isolated large hail and a tornado or
two.

Ahead of the front, high heat and humidity will spread across the
Northeast today.  Heat advisories currently extend along the I-95 corridor
from Philadelphia to Boston and cover much of Upstate New York as well. 
The hot temperatures and high humidity will push heat indices into the
upper 90s and low 100s across much of the region.  By Thursday, as the
previously noted front continues to move east, showers and thunderstorms
are expected to develop across the Northeast.  With these storms will come
the potential for damaging winds, especially across portions of the
eastern New York into New England.

Showers and thunderstorms will also be likely farther south along the
front, with the potential for severe weather as well, especially from the
Carolinas southwestward into the lower Mississippi Valley.

Above-normal temperatures continue across the much of the western U.S. as
well, including the valleys of south-central California, where an
Excessive Heat Warning remains in effect today.  With an additional
increase in temperatures expected later this week, an Excessive Heat Watch
centers along the lower Colorado River Valley into southern Utah, where
daytime temperatures are forecast to soar well above 100 degrees on
Thursday and Friday.

Monsoonal moisture will continue to fuel daily showers and thunderstorms
across portions of the southwestern U.S., with the better chance for
storms centering from eastern Arizona to the central and southern Rockies.
 While widespread heavy amounts are not expected, locally heavy amounts
are possible, which may result in isolated flash flooding, especially
across areas recently impacted by wildfires.

Pereira

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