Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
356 PM EDT Thu Jun 29 2023

Valid 00Z Fri Jun 30 2023 - 00Z Sun Jul 02 2023

...Slight Risks of Excessive Rainfall are in effect over the central US on
Thursday and Saturday...

...There is an Moderate Risk of severe thunderstorms over parts of the
Middle Mississippi and Ohio Valleys on Thursday, and an Enhanced Risk of
severe weather over the Central High Plains Thursday evening...

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

...Air Quality alerts over parts of the Upper/Middle Mississippi Valley,
Great Lakes, Western Ohio Valley, Central Appalachians, Northeast, and
Mid-Atlantic...

A frontal system draped across the central Plains continues to result in
areas of heavy precipitation across central US, including areas of severe
weather. A Slight Risk of Excessive Rainfall (level 2/4) and a Moderate
Risk of Severe Weather (level 4/5) are in effect across portions of the
lower Ohio River Valley into portions of Tennessee as a complex produces
heavy precipitation, hail, and damaging wind gusts. A warm and moist
airmass to the south is helping to provide ample moisture for the current
convective activity across the region. On Thursday evening, the focus for
heavy precipitation will shift toward portions of the north-central
Rockies and High Plains as energy rounding the closed upper low over the
West will interact with a surface boundary in the northern Rockies, which
is forecast to produce heavy precipitation and severe weather across the
region, including regions already saturated with recent heavy rains. A
Slight Risk of Excessive Rainfall and an Enhanced Risk of severe weather
(level 3/5) are in effect over the Central High Plains due to the expected
formation of convection overnight. On Friday, this energy will progress
eastward into the central Plains and Midwest. Given the moist environment
in place, widespread convection is likely to initiate across the region.
As a result, a Marginal Risk of Excessive Rainfall is in effect for much
of central Plains on Friday. On Saturday, the threat for excessive
rainfall increases as southwesterly flow ahead of a surface trough will
force ample moisture into a region of large-scale ascent over the Midwest,
including areas impacted by heavy precipitation on Thursday and Friday. As
a result, a Slight Risk of Excessive Rainfall is in effect across the
Midwest on Saturday.

A deep upper-level trough over portions of New England and the East Coast
is forecast to continue lifting northeastward in the short term, providing
a break from the convective activity that has impacted the region
recently. A slow-moving frontal system at the surface will continue to
progress through eastern New England while slowly weakening. The
combination of modest forcing and terrain-induced lift resulted in a
Marginal Risk for Excessive Rainfall to be issued in portions of
northwestern Maine and the White Mountains of New Hampshire. As the trough
continues to lift northeastward, the threat for heavy rainfall shifts
toward the next system approaching from the Midwest. There are Marginal
Risks for Excessive Rainfall on Friday and Saturday across the region as
locally heavy rainfall amounts are possible ahead of a frontal system
approaching from the Northwest. On Friday, portions of the Ohio Valley and
south-central Appalachians may see locally heavy rainfall ahead of this
system. On Saturday, the threat for heavy rainfall shifts northeastward
into the north-central Appalachians and northern New England. The risk for
flash flooding is heightened in areas that have already seen localized
heavy rainfall recently. Temperatures across the region will remain
relatively seasonal through the forecast period, with a modest warming
trend expected heading into the weekend.

The upper-level ridge centered over the Mid-South is expected to begin
moving east and gradually weaken through Saturday. For portions of
northern and interior Texas, this means that temperatures will be
returning to near seasonal values, though still generally above average.
For the Mid-South and Gulf Coast, hazardous heat is expected through the
end of the work week underneath the upper-level ridge. Temperatures will
near triple digits, with maximum heat indices likely exceeding 110F across
portions of the Mid-South, low-mid Mississippi Valley, and portions of the
Gulf Coast through Saturday. Nighttime lows are expected to be extremely
warm, and potentially record breaking, providing little relief for the
heat at night.

In addition to the current weather activity, Canadian wildfire smoke is
expected to continue impacting portions of the eastern US over the next
few days. However, air quality is expected to improve in the short term as
a combination of thunderstorm activity and dispersion of smoke will
ultimately result in improving air quality conditions for much of the
country heading into the weekend.

Genz


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