textproduct: Des Moines

KEY MESSAGES

- Breezy and dry conditions through the rest of today with gusts near 25mph and highs in the 80s.

- 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 THURSDAY NIGHT/

Issued at 1213 PM CDT Wed Aug 26 2026

A boundary has passed through Iowa overnight and is currently pushing east out of the state. Behind it, drier air has entered the area as evident on water vapor imagery. This leads to dewpoints in the low 60s. Tonight, a surface high moves into the area leading to much lighter winds. This high pressure and light winds may lead to some patchy fog but dewpoints will be too low for widespread fog. While low, patchy fog potential looks best across far southern Iowa.

Dry air remains around the state tomorrow leading to more pleasant conditions with highs in the low to mid 80s. Tomorrow night the high will move out of the area before our next shortwave arrives. The day Friday will still remain dry, although surface flow from the south will lead to warmer air being advected into the state with highs being a few degrees warmer. Despite this southerly flow at the surface, moisture transport is cut off by the influence of the surface high still departing to the east.

Northwesterly flow remains in the midlevels and moisture transport looks much better there. The shortwave will enter the region and enhance the Low Level Jet (LLJ), providing forcing for elevated showers and storms, mainly in northern and western Iowa where more moisture is available. Unsurprisingly, point soundings show there is a fair bit of dry air across northern Iowa that would need to be saturated for rain to reach the ground. If storms do form and move across northern Iowa, this layer of dry air could lead to sporadic gusty winds. If the aforementioned surface high moves farther south than modeled, this could help with better low level moisture and would lead to higher chances for showers and storms. Sounding profiles do look much better across northeastern Iowa as this goes on through Saturday morning as a better plume of low level moisture catches up to this system.

LONG TERM /FRIDAY THROUGH TUESDAY/

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 THURSDAY/

Issued at 1213 PM CDT Wed Aug 26 2026

Prevailing VFR conditions are expected through this TAF period. Breezy winds with gusts up to 25kts are expected at KMCW and KALO, with lower gusts from 15 to 20kts expected at other sites. Diurnal cumulus as low as FL025 may be present in some areas with the greatest coverage in northern Iowa, but will dissipate around sunset. Around sunset, wind gusts will come down and light northwesterly winds are expected. Patchy fog is possible across southern Iowa, but low confidence due to a fairly dry airmass leads to no TAF mentions at this time.

DMX WATCHES/WARNINGS/ADVISORIES

None.