170
FXUS63 KDMX 260344
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1044 PM CDT Fri Jul 25 2025

 ...Updated for the 06z Aviation Discussion...

.KEY MESSAGES...

- Showers and storms will develop over southern Iowa this
  afternoon and expand northward through the evening and
  overnight. Heavy rainfall will be the main concern, and could
  lead to increased flash flooding and river flooding concerns.

- Additional isolated showers and storms are possible southeast
  tomorrow afternoon and evening. Some storms could be strong
  with gusty winds and small hail the main concerns.

- Hot and humid conditions develop Sunday into Monday with heat
  indices over 105 possible both days.

&&

.DISCUSSION...
Issued at 247 PM CDT Fri Jul 25 2025

Showers and isolated thunder over southern Iowa are the first of
what will be intermittent shower and thunderstorm chances lasting
through the evening. These chances will spread northeastward through
the evening bringing the potential for more heavy rainfall to the
area. Fortunately most of the rain last evening stayed outside the
forecast area so soils aren`t as primed as what was anticipated this
time yesterday. However, still anticipating some potential for flash
flood impacts over southern Iowa, primarily in urban areas should
prolonged heavy rain occur over the same area. Rainfall amounts will
generally be around 1 to 3 inches, with isolated pockets of 4 inches
or more certainly possible in some locations over southern into
southeastern Iowa.

Of similar concern will be a lower confidence but potentially
impactful secondary band that develops slightly farther north in a
few of the short range models. This would put a line of slow moving,
training storms over central into north central Iowa, which is an
area that received heavy rainfall earlier in the week. Likewise,
rivers in these areas are already running at increased flows as
water continues to route southward from rain this week. Should this
band of 1 to 3 inch rain fall over one of these basins, the
additional runoff could exacerbate conditions on the rivers, as well
as lead to localized flash flooding as the water works it`s way
through the system. Similarly, any heavy rainfall over urban areas
could cause flash flooding and ponding on roadways. Again, this is a
lower confidence scenario as most of guidance keeps the heaviest
rain over southern Iowa where rivers are less aggravated, but
certainly something to keep a close eye on. If this band displaces
even farther north where flood warnings and watches are already
ongoing, particularly on the Iowa and Cedar Rivers. The Des Moines
River basin is also running at increased flow and could be impacted.

Beyond the heavy rainfall and flash flooding risk, there remains a
low chance for a few stronger storms, particularly in southern Iowa.
The main threat with these storms will be strong winds as rain falls
and the downward mass flux produces increased outflow from the
storms. The storm prediction center currently has a marginal
risk for severe weather just south of the forecast area and
barely clipping our southeastern counties, but gusty winds are
possible farther north of this area as well. Precipitation
lingers into Saturday morning but should mostly wrap up through
mid-day. Some guidance suggests isolated redevelopment in the
southeast Saturday afternoon, but this will be fairly sporadic.

The next hazard on deck is the hot and humid conditions that develop
Sunday into Monday as thermal ridging/warm temperatures aloft leak
eastward into the forecast area. Highs Sunday and Monday will be in
the low to mid 90s, with dewpoints pushing the upper 70s to near 80
in some locations. This would push heat indices into the 105 to 110
range, likely warranting heat headlines on Sunday and Monday. Monday
is currently forecast to be the warmest day, however, guidance has
begun to key in on a shortwave dropping southward into the forecast
which could impact high temperatures on Monday. This wave may also
bring some severe potential to the area, with SPC pulling the
marginal risk for severe weather.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1040 PM CDT Fri Jul 25 2025

Showers and thunderstorms will continue to lift northeast from
Missouri and Kansas after 06z. KDSM and KOTM are the primary two
sites that may be impacted by this activity. Less confidence in
precipitation chances after 14z and have opted to keep mention
out at this time. MVFR to IFR stratus may also develop at all
sites tonight into Saturday morning. Cigs will gradually improve
then late morning and into the afternoon. VFR conditions are
anticipated to end the period. Light wind through most of the
period.

&&

.HYDROLOGY...
Issued at 247 PM CDT Fri Jul 25 2025

With upcoming heavy rainfall in the south this evening, and the
potential for a secondary band of heavier rainfall slightly farther
north in the area, there will be a risk for additional impacts on
area rivers this evening into Saturday. Basins of greatest concern
will be the Iowa and Cedar River basins, which already have multiple
sites approaching minor flood stage. Additional heavy rainfall of 1
to 3 inches within these basins could compound with the already
elevated river levels and exacerbate flood concerns. Similarly, the
Des Moines River basin is running at elevated levels, although no
sites are currently expected to approach flood. This could change if
the heavier band occurs. The Cedar River basin is at a lower risk of
being directly impacted by this band, but is only slightly displaced
from the expected area. The Iowa River basin and Des Moines River
basins being farther south will be at a greater risk for being
impacted by this band, which could push sites into flood stage that
weren`t previously expected, especially those between the Highway 30
and Interstate 80 corridors. Urban areas will also be at risk for
flash flooding, especially as runoff routes into already elevated
streams. &&

.DMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Saturday morning for IAZ059>062-071>075-
081>086-092>097.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Saturday morning for IAZ059>062-071>075-
081>086-092>097.

&&

$$

DISCUSSION...Dodson
AVIATION...Donavon
HYDROLOGY...Dodson