textproduct: Des Moines

KEY MESSAGES

- Showers and storms will be possible through the day as a cold front moves through the area. The severe weather threat is low.

- Storms are possible Saturday night and early Sunday followed but much warmer and more humid conditions for early next week.

SHORT TERM /THROUGH THURSDAY/

Issued at 300 AM CDT Wed Jun 24 2026

The latest surface analysis places the area ahead of an approaching cold front. This front is associated with an occluding 1013 mb surface low centered over Minnesota. Showers with scattered embedded thunderstorms continue across northwestern Iowa as a convective complex tracks southeastward. Outside of the ongoing convection, surface high pressure centered over the Ohio Valley is promoting clear skies, with temperatures falling into the upper 50s and lower 60s.

Through the remainder of the overnight hours and into early morning, the convective complex is forecast to track southeastward. SPC Mesoanalysis indicates a few hundred J/kg of both MLCAPE and SBCAPE ahead of this complex, which will help sustain the system and support embedded thunderstorms. By this afternoon, the upper-level circulation and trough are expected to become less defined and diffuse into the jet stream. However, the presence of the weak cold front, ongoing convection, and diurnal instability building will support renewed chances for showers and thunderstorms across southeastern portions of the CWA. Once the front moves east of the region, shower and thunderstorm coverage will decrease. Outside of any convection, temperatures today are expected to climb into the low to mid 80s.

Behind the departing front, post-frontal surface high pressure will build into the area late this evening and persist into Thursday. Overnight tonight, temperatures will fall into the lower 50s across the northwest to the lower 60s in the southeast. A few isolated cooler locations are possible under the post-frontal CAA regime and partly cloudy skies. Guidance indicates that the system which moved through Tuesday and Wednesday morning will reorganize downstream as the upper-level trough and embedded jet streak strengthen as they approach the Great Lakes. This will allow PoPs to increase throughout the day Thursday, mainly for areas along and south of the I-80 corridor. High temperatures on Thursday will top out in the mid to upper 70s under increasing cloud cover and returning shower and thunderstorm chances.

An approaching cold front and low pressure system will drive showers and thunderstorms southeastward through Wednesday, with renewed storm development expected in the southeastern CWA this afternoon before the front exits. High pressure brings a brief cooling trend tonight, but a reorganizing upper-level trough near the Great Lakes will return cloud cover and precipitation chances to the area on Thursday.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/

Issued at 207 PM CDT Tue Jun 23 2026

Zonal/westerly flow aloft will be in place Thursday and Friday. Still monitoring the evolution of building lower Mississippi Valley sub-tropical high and and upper low descending into the western CONUS. This will lead to a strong push of warm advection across Iowa as a steepening southwest flow develops. This may bring a few thunderstorms to the state followed by heat and humidity for Sunday and into early next week. Heat index values could approach 105 degrees in some areas. At some point, the evolution of the western trough relaxing and the sub-tropical high nudging north, may lead to the ring of fire MCS complexes rolling along the northern periphery of the sub-tropical high and potentially impacting Iowa.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1000 PM CDT Tue Jun 23 2026

VFR conditions are expected to prevail at all sites through this TAF period. The challenge this period is with showers and thunderstorms in northern Iowa which may impact KMCW and KALO. Confidence has decreased in storm coverage as far west as KFOD, so the previous PROB30 was dropped. Given current trends, the chance of thunderstorms is greatest at KMCW before 10z. Depending on storm coverage, a brief window for storms at KALO exists between 08z and 12z, though confidence is lower. Otherwise, winds will be light and variable in southern Iowa with west to northwest winds under 15kts across northern Iowa.

DMX WATCHES/WARNINGS/ADVISORIES

None.