textproduct: Des Moines

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.