textproduct: Des Moines

KEY MESSAGES

- Periodic chances for storms through Monday, mainly over the western half of Iowa. Damaging winds are possible with storms.

- Gradual cooling into Monday followed by more seasonal temperatures.

SHORT TERM /THROUGH TUESDAY/

Issued at 239 PM CDT Sat Sep 5 2026

Convective debris and an outflow boundary impacted parts of central and northern Iowa today. The outflow boundary has been eroding early this afternoon but this boundary in addition to the clouds, have kept the Highway 30 corridor and northward cooler yet still humid today. A few showers did linger over far north central Iowa but trends have continued downward.

That Convective trends will the primary challenge over the next 36- 48 hrs. There is already diurnally driven isolated thunderstorms over far northern Missouri. This potential may reach far south central Iowa where agitated cumulus along a wind shift line is present. The low level jet will ramp up again tonight across the western High Plains while the instability axis does move farther east into central Iowa. Thunderstorms are expected to develop over parts of South Dakota and southwest Minnesota and eventually become organized and follow the Corfidi vectors southeast into Iowa along the instability axis. These storms may pose a damaging wind threat later tonight and into Sunday morning. This process may repeat again Sunday night into Monday morning. The elevated mixed layer (EML) is expected to become re-established Monday afternoon and should end precipitation chances for a period. An upper level low moving into Montana then Manitoba will squash the upper ridge enough to allow a boundary to enter Iowa by Tuesday, which will bring the next chances for thunderstorms and cooler weather.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

Issued at 239 PM CDT Sat Sep 5 2026

The flattening of the sub-tropical high will continue Wednesday with a westerly/zonal flow for the mid to end of the week. Less certainty late next week with spatial and temporal differences with the next strong upper level short wave that will arrive into the Pacific Northwest. This will determine how much the sub-tropical high ridging can become re-established over the western CONUS and the difference between seasonal westerly flow or cooler northwest flow and attendant precipitation chances associated with each.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 629 PM CDT Sat Sep 5 2026

VFR conditions prevail over the area this evening, although a FEW to SCT cloud deck around 1500 to 2500 ft is still floating around out there. Remnant boundaries could lead to brief, isolated showers through this evening, but chances of this are low so have not included in TAFs.

Later tonight and into Sunday morning, shower and storm chances will increase, primarily at KFOD, KMCW, and KDSM. While rain chances are higher later tonight, coverage will be scattered, so have stuck with PROB30 mention at impacted terminals. Conversely, in areas that remain clear tonight, some patchy fog is possible. This seems most likely over northern and eastern Iowa, specifically KMCW, KALO, and KOTM. That said, if showers occur at KMCW, fog will be less of an impact. A break in precipitation is expected through Sunday morning, with more rain and storm chances pushing into western Iowa Sunday afternoon, mainly impacting KFOD and KDSM.

DMX WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 7 PM CDT this evening for IAZ033>039- 044>050-057>062-070>075-081>086-092>097.