textproduct: Des Moines

KEY MESSAGES

- Marginal Risk for severe weather in northwest Iowa for tonight. Hail will be the main threat.

- Marginal Risk for severe weather in northern and northwest Iowa for Monday afternoon/evening. Hail and damaging winds both possible.

- Extended forecast trending more dry for the work week, but precipitation builds back in to start next weekend.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 228 PM CDT Sun May 24 2026

A quite and fair Sunday featured little to no clouds. Highs this afternoon will eclipse 80 degrees most everywhere. 12z CAM guidance simulated showers and storms in northwest Iowa this afternoon and evening, the culprit being storms that initiated in Nebraska and South Dakota. These storms have yet to materialize out there, so have continued to hedge towards the later arrival. The Marginal Risk for storms tonight remains tucked just west, focused more with the instability axis. The low-level relative wind max will be pulled into northern Iowa throughout Monday, extending the timeframe of showers and storms at least through late morning. Shower and storm chances have be introduced further south as a few could form on the eastern edge of the instability axis. A Marginal Risk was added in for Monday afternoon as destabilization pushed MUCAPE north of 2000 J/kg with deep layer shear of around 30kts. Hail will be the main risk, with damaging wind potential in the daytime hours. Storm motion will be slow, and the Corfidi vectors start pointing to the west after dark. Locally heavy rain exceeding 2" will be possible with storms.

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 228 PM CDT Sun May 24 2026

The moisture axis responsible for Monday's storms will be ushered north by the building ridge. The blocking pattern still favors highs in the 80s, and now trends favor the moisture profile keeping southwest of the area for most of this week. Models diverge on how to handle the arrival of high pressure this weekend, which will affect where the moisture pool will move. A more eastward shift like the ECMWF's would mean active weather, whereas a more centered, faster solution like the GFS spells an extension of seasonal, dry conditions.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1233 PM CDT Sun May 24 2026

Monitoring the 00-03z window for KFOD as showers and storm development is being monitored in Nebraska. Guidance, while not initializing well, has consensus on showers and storms impacting this terminal in the given time window. Left out for now as development has underperformed expectations already, but will amend as necessary.

Refined Prob30 groups in the extended and added prevailing -SHRA to KMCW in the planning period. An extension of showers may reach as far south as KDSM, but confidence is low enough to leave out of the TAF at this time.

DMX WATCHES/WARNINGS/ADVISORIES

None.