textproduct: Des Moines

KEY MESSAGES

- Cooler temperatures will be in place through the work week before another warmup this weekend.

- Showers and a few storms this evening through Friday morning across central and southern Iowa. Pockets of heavy rain are possible, especially in southwest Iowa.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 232 AM CDT Thu Jul 23 2026

High pressure remains firmly in place across the area early this morning, while to the west an embedded shortwave is riding the thermal ridge and will make another run at western Iowa later today. Upper level moisture has begun to stream in aloft with increasing cloud cover overnight. The incoming low will still have to battle substantial dry air and it will take most of the day for profiles to sufficiently saturate. With the thermal ridge still off to the west and precipitation not yet into the area, today will be another rare cool July day.

By late afternoon into the evening better moisture arrives, thanks in part to the increasing low level jet. Warm cloud depths remain 4000+ m along with PWATs exceeding 2". An important change is a shift in the track of the shortwave, which does not make it as far east as earlier guidance suggested. This shifts the expected axis of precipitation slightly to the west with the heaviest rain now expect to fall west and south of the area. Even so, conditions favor efficient rain productions once the column sufficiently saturates overnight and pockets of heavy rain are possible, especially in southwest Iowa. While dry antecedent conditions and mature crops will help to mitigate most hydro concerns problems may still be possible, especially in town. The shortwave is expected to skim south of the area on friday with rain tapering off across Iowa through the morning. This will be the final cool day for the midwest with the western US thermal ridge beginning to shift east.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 210 PM CDT Wed Jul 22 2026

Ensembles continue to suggest the central Plains ridge strengthens and advances eastward on Saturday. This will bring in heat by Saturday afternoon, and even warmer temperatures Sunday. Temperatures near 90 appear likely Saturday, and perhaps mid 90s by Sunday. Tropical storm Bertha will be nothing more than a breeze by the weekend and should allow for an open gulf moisture stream. Evapotranspiration is also near its peak at this point in the summer. At this time, it looks like dewpoints will rise to at least the mid 70s. This would adjust apparent temps up by several degrees and give us potential for 100+ heat indices Saturday through Monday in some locations. The position of the ridge and fairly strong mid- level flow Sunday into early-week will put our area in ring of fire position with potential for several rounds of strong storms. High instability and potential for a decent nocturnal LLJ makes Sunday into Monday the current best estimate for the next chances at severe weather, but details are unclear at this time. The jet pattern becomes less clear after Monday, and confidence in storm chances is low beyond Monday.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 638 AM CDT Thu Jul 23 2026

VRF conditions will prevail through the day with increasing high clouds across all sites. Deeper saturations begins after 00z with -SHRA expected at sites KFOD/KDSM/KOTM after 06z. Chances are highest in southwest Iowa and have included a prevail group at KDSM which is nearest this. Prob30 groups have been used at KFOD which is on the northern edge and KOTM which will have the latest onset time. Adjustments are likely.

DMX WATCHES/WARNINGS/ADVISORIES

None.