textproduct: Des Moines

KEY MESSAGES

- Mostly sunny, light winds, and highs in the 80s today.

- Shower and storm chances return Friday night into Saturday morning. Additional storm chances will continue through the weekend and next week.

- A pattern change will lead to warming temperatures and higher humidity. Heat indices will be in the 90s.

SHORT TERM /THROUGH FRIDAY/

Issued at 1233 AM CDT Thu Aug 27 2026

High pressure will continue to drive the weather for the next two days. Light winds and highs in the 80s will be found statewide. Mostly clear skies and dry conditions will add to the comfortability factor. On the note of dry conditions, correction of the NBM high bias to dew points was needed the next two days. This is due to dry air advection along northerly flow, which is bringing in sub- seasonal values.

CAMs do try and leak in some diurnal showers and storms in northwest Iowa Friday afternoon, but poor lapse rates in the midlevels and the lack of moisture will keep updrafts, if any, thin and weak. Chances <10% are justifiable given these factors.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Issued at 1213 PM CDT Wed Aug 26 2026

Behind the showers and storms Saturday morning, breezy conditions are expected due to a tight pressure gradient and strong flow at the low levels. High pressure is still pancaking the Four Corners region leading to a broad upper level ridge and keeping Iowa in northwest flow through Saturday. Over the weekend the high is expected to weaken as the ridge is broken down by a potent trough that enters the Pacific Northwest. This will end up leading to a pattern change with warmer temperatures and more humid conditions through the end of the weekend and into next week. As the pattern changes, additional storm chances are possible with any shortwave that rides eastward across the broad upper-level ridge.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1232 PM CDT Thu Aug 27 2026

Cumulus development continues to expand in coverage over the forecast area, with ceilings near MVFR in spots but should generally remain VFR. Clear skies are expected to return after 00z this evening, with winds becoming variable and very light to calm into Friday morning. A signal exists at this time for patchy fog development into the morning, though confidence on this development and coverage is quite low at this time, so have not included at any terminals and will continue to monitor trends.

DMX WATCHES/WARNINGS/ADVISORIES

None.