679
FXUS63 KDMX 011144
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
644 AM CDT Thu Oct 1 2026

 ...Updated for the Hydrology Discussion...

.KEY MESSAGES...

- Moderate to heavy rainfall continues this morning. Flash
  flooding remains possible, and river flooding likely.

- Rain this morning tapers off from northwest to southeast
  through the day today, with potential for an additional 1 to 2
  inches over southern into southeastern Iowa this afternoon.

- Once rain ends across the area today, cooler, drier and
  breezier conditions develop with dry, fall-like weather
  through the weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 216 AM CDT Thu Oct 1 2026

This morning`s heavy rainfall has generally moved out of the
area, and a trailing cold front has begun to push southward.
Some light drizzle/mist is accompanying this front but overall
should end the rainfall from northwest to southeast through the
day. Barring a few elevated showers, much of the forecast area
should see rain ending by noon, if not sooner. Before
completely pushing out of the area this afternoon, we may see
showers and even a few storms fester along the boundary in
southern and southeastern Iowa. These will have the potential to
bring another 1 to 3 inches to southeastern Iowa, although it`s
possible this secondary band ends up south and east of our
forecast area. Regardless, given the widespread rain that fell
yesterday and saturated soils over southern Iowa, WPC has
maintained a slight risk for excessive rainfall (level 2 of 4)
to account for this secondary swath of rain in southeastern Iowa
later today. The Flood Watch continues through this evening.

Behind the cold front today, conditions over Iowa will be drying out
and cooler air filling in. Slightly enhanced pressure gradients
combined with the cooler, descending air mass will lead to some
breezy post-frontal conditions today. Northerly winds of 15 to 20
mph are expected today, with gusts up to 30 mph especially over
northern Iowa.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 328 PM CDT Wed Sep 30 2026

The extended forecast period is expected to mark the first true
transition to fall-like weather. Behind Thursdays cold front,
surface high pressure will build back into the region, bringing
several days of dry weather and cooler temperatures. Previous
forecast iterations depicted a shortwave diving southeastward toward
the upper Mississippi River Valley, but this afternoons model
guidance has largely removed that feature, leaving the area mostly
dry until precipitation chances return late in the period.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 618 AM CDT Thu Oct 1 2026

The heavy rain overnight has mostly moved out of the area, but
lingering light rain/drizzle continues to impact TAF sites this
morning. This is resulting in occasional visibility reductions,
primarily around 3 to 6 SM. Ceilings have begun to improve to
VFR over northern Iowa, although occasional MVFR to IFR ceilings
continue central and south. Additional rain and showers remain
possible this afternoon, mostly impacting KDSM and KOTM. A cold
front passing through the area this morning is also flipping
winds to a northerly direction, and will eventually produce some
breezy winds with gusts around 20 to 25 kts. Any remaining
precipitation should diminish by late this afternoon or early
evening, with clouds clearing out overnight into Friday morning.


&&

.HYDROLOGY...
Issued at 644 AM CDT Thu Oct 1 2026

Thus far, rain amounts underachieved vs. forecast amounts Wednesday
evening across much of the CWA. The heaviest amounts fell
approximately along an axis from Carroll to Waterloo. Additional
rain is expected through midday today with the heaviest amounts
mainly across the southern CWA, however forecast amounts have
trended down from previous forecasts too.

As a result, flash flood concerns have trended down from Wednesday
evening but are still elevated. Some flash flood warnings are in
effect. River forecasts have trended down as well on many rivers,
with peak stages expected a little later at many locations. Multiple
river flood warnings remain in effect and some have been canceled,
however a flood watch remains necessary because some rivers may
still reach flood stage but confidence is below the 80% threshold
typically needed for flood warnings. Further adjustments to river
forecasts are likely today into Friday, to fine-tune timing and
stages.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for IAZ024>028-033>039-
044>050-057>062-070>075-081>086-092>097.

&&

$$

SHORT TERM...Dodson
LONG TERM...Vorst
AVIATION...Dodson
HYDROLOGY...Zogg