Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
405 AM EDT Thu Jul 21 2022

Valid 12Z Thu Jul 21 2022 - 12Z Sat Jul 23 2022

...Dangerous heat to continue impacting portions of the southwestern,
south-central, and eastern U.S....

...Severe thunderstorms possible across the sections of the Northeast and
the Southeast today...

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

Above-normal temperatures will continue to prevail across much of the U.S.
through the end of the week, with a significant portion of the population
remaining under heat-related advisories and warnings. 

In the Southwest, an Excessive Heat Warning for today and tomorrow extends
from southeastern California and western Arizona northward into southern
Nevada and southern Utah.  Daytime temperatures are forecast to soar well
above 100 degrees across much of the region both days -- topping 110 in
many lower elevation locations.  Overnight lows are likely to remain in
the 80s in many spots, providing little nighttime relief.

Farther to the east, monsoonal moisture is forecast to fuel daily showers
and thunderstorms from eastern Arizona into the southern Rockies.  While
widespread heavy amounts are not expected, storms that develop may have
the potential to produce locally heavy accumulations, with isolated flash
flooding possible.

From the southern Plains to the lower Mississippi and Tennessee valleys, a
weak front that has dropped in the region is expected to bring
thunderstorms and some relief to parts of the region today.  However it
will remain quite warm and humid across the much of the region, with heat
advisories continuing to cover portions of eastern Oklahoma and Texas, as
well as much of the lower Mississippi and parts of the Tennessee valleys. 
Temperatures are expected to remain above average through the period, with
daytime heat indices expected to climb above 100 degrees across much of
the region each day.

The heat is expected to build to well above-average across the across the
central Plains and mid Mississippi Valley today, and into the northern
Plains and upper Mississippi Valley by Friday, before a cold front brings
some notably cooler temperatures into the northern Plains and the upper
Midwest beginning Saturday.

Farther east, a slow-moving cold front will continue advance south and
east from Ohio Valley, bringing showers and storms into the eastern U.S.
today.  Some of these storms may become strong to severe, especially
across portions of the Northeast and Southeast.  From eastern New York
into New England and from the lower Mississippi Valley to the Carolinas,
conditions are expected to become favorable for storms producing damaging
winds across those areas today.  Ahead of the front, very warm and humid
air will remain in place along the East Coast.  Heat advisories extend all
the way from the eastern Carolinas to New England, where the heat combined
with the humidity will support heat indices in the upper 90s and lower
100s in many locations today.

Pereira

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