textproduct: Des Moines

KEY MESSAGES

- Flood Watch remains in effect for southeast Iowa this evening. Heavy rain continues to trend south.

- Brief break from rain Thursday followed by storm chances, some severe, Friday and Saturday.

- Active pattern continues through much of the forecast.

SHORT TERM /THROUGH FRIDAY/

Issued at 250 PM CDT Wed Aug 5 2026

Showers and storms continued across the southeast this afternoon, leaving a swath of 3-5" of rain in its wake in parts of southwest Iowa. Have maintained the Flood Watch for flash flooding in southeast Iowa for the remaining storms as well as the chance of storms to form later on this evening. That said, confidence is decreasing in flash flood potential within the watch. The continued precip today, the instability axis has been pushed into Missouri and the synoptic cold front was already out of the state earlier this morning. The LLJ nose will come close to the state line tonight, but the factors mentioned above favor the max of QPF staying out of Iowa. This solution is supported by CAM guidance this afternoon.

Dense fog will form tonight as the winds calm. Highest confidence in dense fog will be where most of the rain fell over the last 24 hours. Anticipate visibility reductions for the morning commute. A Dense Fog Advisory will likely be issued later on tonight. A reprieve for precipitation comes on Thursday and smoke will filter the sky above. Highs will be near 80 degrees.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Issued at 250 PM CDT Wed Aug 5 2026

The relief from rain will be fairly short lived as an active weather pattern sets up. An upper-level ridge sets up in the desert southwest and locks Iowa in northwest flow for the remainder of the forecast period. We start seeing effects on Friday when moisture returns. Severe weather is possible Friday when storms fire on the instability gradient with 40kts of deep-layer shear to work with. Will need to monitor for supercell potential as the shear orientation is orthogonal to the boundary. If supercells materialized, the hail threat increases due to most of the shear residing above the inflow layer and the steepening lapse rates from the reestablished EML. The front will reorient itself for Saturday, but severe weather will remain in play as instability quickly recovers and deep-layer shear remains favorable across the state.

Northwest flow continues into next week with multiple chances for thunderstorms and high temperatures heavily dependent on storm placement. This pattern continues into next weekend, as highlighted by the CPC 8-14 day outlook.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1032 PM CDT Wed Aug 5 2026

Fog will develop across the area overnight, along with expanding and lowering ceilings. This will result in periods of IFR conditions or lower at all terminals, but timing and magnitude of visibility reductions is particularly difficult to predict. Overall, the lowest conditions will be between about 09-13Z and have indicated this in the 06Z TAFs, but amendments are anticipated overnight based on short-term observational trends. Conditions will then improve rapidly after sunrise, with VFR from 14Z or 15Z through the end of the TAF period.

DMX WATCHES/WARNINGS/ADVISORIES

None.