929
FXUS01 KWBC 171930
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
327 PM EDT Thu Jul 17 2025

Valid 00Z Fri Jul 18 2025 - 00Z Sun Jul 20 2025

...Active thunderstorm pattern will bring the threat of flash
flooding and severe weather along a slow moving cold front
stretching from the Northeast/Mid-Atlantic to the Central Plains...

...Slow moving low to bring significant heavy rainfall and
scattered to numerous instances of flash flooding to the Central
Gulf Coast...

...Widespread major heat risk across the East Coast, Ohio Valley,
Southeast, and Lower Mississippi Valley...

A slow moving, sometimes quasi-stationary cold front stretching
from the Northeast/Mid-Atlantic west through the Midwest and into
the Central/Southern Plains will provide the focus for scattered
to widespread thunderstorms over the next couple of days. A
moisture-rich airmass remains in place, providing the fuel for
efficient, very heavy downpours and instability for severe
weather. Tonight, one area of concern will be from the
Central/Southern Appalachians west through the Ohio Valley and
into the Middle Mississippi Valley/adjacent Southern Plains.
Ongoing storms along the front/effective boundary will
re-intensify and expand in coverage with daytime heating, with
storm motions parallel to the east-west boundary leading to the
potential of repeated rounds of heavy rainfall. A Slight Risk (at
least 15% chance) of Excessive Rainfall is in effect for the
threat of scattered flash flooding. Farther west, storms also will
focus along the boundary/moist upslope flow across portions of the
Central/Southern High Plains, with another Slight Risk in effect
for additional scattered flash flooding. In the interior
Northeast, an upper-level shortwave passing over the cold front
will help provide locally greater shear to support some more
organized/intense thunderstorms capable of severe weather, with
the Storm Prediction Center introducing a Slight Risk (level 2/5)
mainly for the threat of some damaging winds. The cold front will
make southeastward progress across the Northeast/Mid-Atlantic on
Friday, with the greatest coverage of thunderstorms expected along
a frontal wave across portions of central and Tidewater Virginia
into coastal North Carolina. Another Slight Risk of Excessive
Rainfall is in effect for the threat of scattered flash flooding.
More isolated storms and instances of flash flooding can be
expected west along the boundary through the central/southern
Appalachians into the Ohio/Tennessee/Middle Mississippi Valleys.
To the northwest, the front is anticipated to lift north as a warm
front into the Upper Mississippi Valley throughout the day.
Thunderstorms are expected to develop along the leading edge of
the warmer air/low-level jet lifting northward and grow in
coverage into the overnight hours, with a Slight Risk for
scattered flash flooding here as well.

To the south, the National Hurricane Center continues to monitor a
slow moving area of low pressure along the north-central Gulf
Coast. Regardless of any further development of this tropical
disturbance, thunderstorm activity around the low and plentiful
Gulf moisture will bring the threat for torrential downpours. A
Moderate Risk (at least 40% chance) of Excessive Rainfall is in
place along the south-central Gulf Coast of Louisiana following
the expected track of the low and where the greatest confidence of
significant heavy rainfall totals and scattered to numerous
instances of flash flooding exists. A broader Slight Risk is in
place across the central Gulf Coast where more scattered instances
of flash flooding are expected. The threat will continue into
Friday, with another Slight Risk along the central Gulf Coast and
extending farther north across central Louisiana and far eastern
Texas as thunderstorm coverage expands inland. Elsewhere, an
upper-level shortwave will help trigger thunderstorms across
portions of the Northern High Plains tonight. Moist upslope flow
will support enough instability for some more organized
storms/severe weather potential, with a Slight Risk from the SPC
mainly for the threat of large hail. An active Monsoonal pattern
continues in the Southwest/Four Corners region, with scattered
thunderstorms expected daily and a threat for isolated flash
flooding, especially for terrain sensitive areas as well as burn
scars.

Uncomfortable heat continues this week across most of the eastern
U.S. from the East Coast west into the Ohio Valley/Southeast and
Lower Mississippi Valley. Highs into the 90s combined with the
very muggy airmass that has plagued the region has led to
widespread coverage of Moderate to Major Heat Risk (levels 2-3/4),
indicating a level of heat that can affect anyone without access
to air conditioning or adequate hydration. The passage of the cold
front across the Northeast/northern Mid-Atlantic will bring relief
to these areas Friday. Unfortunately, the heat looks to continue
across the Southeast/Lower Mississippi Valley and expand into the
Middle Mississippi Valley and Central Plains this weekend.
Forecast high temperatures look to also remain above average and
into the 90s across most of the Pacific Northwest and into the
Great Basin. Onshore flow along the Pacific Coast and Monsoonal
moisture in the Southwest/Four Corners region will keep
temperatures below average for these areas. Forecast highs range
from the 60s and 70s along the Coast, 70s to 80s for the Four
Corners region, and 90s to low 100s for the Desert Southwest.
Temperatures have begun to moderate some across the
Northern/Central Plains and Upper Mississippi Valley following an
almost Fall-like cold front passage. Highs into the 80s and 90s
will return to most locations outside of the Upper Midwest by
Friday. Highs remain around average in the southern Plains, with
mostly 90s expected.

Kebede/Putnam

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


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