textproduct: Des Moines

KEY MESSAGES

- Overcast skies today with lingering drizzle through the mid afternoon, mainly north and east. Highs in the upper 60s.

- Dry and mild weather Monday with highs in the lower 70s.

- High confidence in widespread and repeated rain chances by mid next week, with renewed flooding concerns and a few thunderstorms.

SHORT TERM /THROUGH MONDAY/

Issued at 133 AM CDT Sun Sep 27 2026

High moisture content wafted in the air over Iowa overnight. The 00z OAX sounding had PWATs within a tenth of an inch of the daily max for the day. Steady rain circulated around an MCV in southern Iowa and showers and a few storms. Drizzle was common beneath the stratus in northwest Iowa. Trended highs lower today as clouds and drizzle will delay their departure until the afternoon. Extended precip mentions until around 20z in the north and east. This is where deep saturation hangs on the longest. Shear and lift are negligible during the day, but its hard to discount near saturation up to 400mb in the soundings and low-level condensation pressure deficits below 10mb. High pressure will chew away at the moisture in the east in the afternoon, but the easterly flow will keep stratus in play into Monday. Rain chances will pause until Tuesday. Western Iowa will hang onto low-level saturation which will allow for fog development Sunday night into Monday morning, aided by light winds under 5kts. Enough dry air may triumph in southeast Iowa to allow for some sunshine in the afternoon, otherwise the rest of the state will be mostly cloudy.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/

Issued at 258 PM CDT Sat Sep 26 2026

The dry weather is short lived, as Tuesday looks like the first of several more rainy days with renewed flooding potential. By Tuesday, the western trough is cutoff from the main flow and slowly makes its way towards Iowa, leaving the area sitting beneath several days of southwest flow. Particularly on Tuesday and Wednesday and perhaps Thursday, a slow moving surface boundary looks to set up SW to NE over Iowa with repeated flare ups of the LLJ and a persistent moisture plume with PWATs of 1.5-2". The wild card in all this is the behavior of Hurricane Polo, whose remnants at mid levels may make it past the Sierra Madre mountains in Mexico and help to enhance the gulf moisture transport ahead of the cutoff low. The result is high confidence in repeated rounds of heavy rainfall and a few thunderstorms mid week. WPC QPF guidance shows widespread 48hr totals near 2-4", and the threat for localized higher totals due to training thunderstorms is definitely present. Given already high soil moisture content, expected totals will be enough to bring up flash flood and river flood threats. Experimental HEFS guidance has a 50% chance that many central and southern Iowa rivers and streams reach or exceed action stage and border on minor flood stage next week, and a 30% chance that some (Raccoon/Skunk/Thompson) reach minor to moderate. With so many moving pieces on the synoptic and mesoscale, trends will need to be monitored and changes are expected.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 610 AM CDT Sun Sep 27 2026

Main challenge will be IFR/LIFR cigs from stratus paired with local MVFR vsby restrictions from fog/drizzle. Rain has trended nearly stationary in southeast and eastern Iowa, so extended shower mentions for KALO, KOTM, and KDSM. Drizzle has been added to TAFs, lasting the longest at KMCW and KALO. Fog looks probable tonight given the rain and weak winds and refinements to restrictions will be added in later issuances.

DMX WATCHES/WARNINGS/ADVISORIES

None.