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