804
FXUS01 KWBC 171936
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
335 PM EDT Sun Aug 17 2025

Valid 00Z Mon Aug 18 2025 - 00Z Wed Aug 20 2025

...Rounds of thunderstorms with a heavy rainfall and flash flood
threat for the Upper Midwest through Monday...

...Scattered thunderstorms expected across portions of the
Northeast/Carolinas, Florida/Gulf Coast, and Southwest the next
couple of days will bring an isolated threat of flash flooding...

...Hazardous heat builds across parts of the Plains, Midwest, and
Mid/Lower Mississippi Valley through early this week...

A slow moving frontal system will trigger additional rounds of
thunderstorms across much of the Upper Midwest through Monday.
Plentiful moisture and instability will promote heavy downpours
with organized clusters of thunderstorms contributing to
long-duration rainfall and heavy totals. There is a Slight Risk of
Excessive Rainfall (level 2/4) covering portions of the eastern
Dakotas, central/southern Minnesota, western Wisconsin and
northern Iowa where scattered to potentially numerous instances of
flash flooding can be expected through this evening and overnight.
As the system progresses eastward Monday, another Slight Risk is
in place across  portions of southern Wisconsin, northeast Iowa
and northern Illinois for additional scattered instances of flash
flooding. As the frontal system finally gains some forward
momentum, the flash flood risk diminishes somewhat as it shifts
southward into the central Plains, Mid-Mississippi Valley and
parts of the Ohio Valley by Tuesday.

Scattered to widespread thunderstorms are also expected across
much of the eastern U.S the next couple of days. Across the north,
storms along and ahead of a cold front pushing through the
Northeast/Ohio Valley/Mid-Atlantic this evening and into the
Carolinas/southern Appalachians Monday may lead to some isolated
instances of flash flooding. Additional storms are forecast across
the Florida Peninsula and westward along the central Gulf Coast to
start the week, with a greater risk for heavier rainfall/isolated
flash flooding through this evening. Farther west, surges of
monsoonal moisture into the Four Corners region will continue to
spark daily isolated to scattered showers and thunderstorms, some
of which will be capable of producing downpours and spotty
instances of flash flooding. This will especially be the case near
burn scars and steep terrain. Additionally, while heavy
rainfall/winds are expected to remain well offshore the East Coast
as Hurricane Erin passes by to the east this upcoming week,
life-threatening surf and rip currents are expected and will begin
possibly as early as Monday.

Conditions will remain very hot and muggy over portions of the
eastern Plains, Midwest, and Mid/Lower Mississippi Valley through
the early part of this week. Heat Advisories cover much of the
region as heat indices top out in the 105-110 degree range. In
addition, lows in the mid-to-upper 70s will bring little relief
from the heat overnight. Across the Northeast and Mid-Atlantic, a
cold front will bring relief on Monday as highs fall into the 70s
for most locations. This relief from the stifling heat and
humidity should last through most of the week. Elsewhere, forecast
highs will also remain seasonably hot and into the 90s across the
Southeast, Gulf Coast, and northward through the Plains into
Monday and Tuesday. A growing upper-level ridge will bring hotter
temperatures to the Intermountain West as well with highs rising
into the 90s to near the triple digits Monday into Tuesday.
Meanwhile, portions of the Upper Midwest/Great Lakes north of a
frontal boundary will remain unseasonably cool, with highs in the
60s and 70s. Temperatures across the West Coast will also remain
below average through midweek, with 60s and 70s expected.


Miller/Putnam


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