textproduct: Des Moines

KEY MESSAGES

- Shower and thunderstorms continue over the area this afternoon. Some storms may be severe in southwest Iowa, with all severe hazards possible. See update section for details on ongoing weather.

- Dry and warm conditions develop on Friday.

- Shower and thunderstorm chances return Saturday. A few strong to severe storms are possible.

UPDATE

Issued at 1111 AM CDT Thu Jun 11 2026

Our morning thunderstorms have pushed through the area, and we now look ahead to additional development through mid-day into the early afternoon. The surface low currently resides over south central Iowa, with the cold front draped over southwest Iowa and the warm front extending east from central into eastern Iowa. This wave will be tracking east northeast through the next few hours, continuing to advect warm, moist air up into southern Iowa. There are scattered clouds/showers muddying the skies in southern Iowa, which may limit atmospheric recovery some, but this system is likely dynamic enough to overcome the patchier sunshine.

Models and forecast output from SPC mesoanalysis all show destabilization occurring in southern Iowa today, reaching nearly 3000 J/kg of surface based CAPE. To compliment this unstable air mass will be an impressive wind field showing strong speed and directional shear through the entire layer, thanks to a stout 60 kt 500 mb jet, a 30 to 40 kt 850 mb jet, and south southeasterly surface flow. The result, is large, looping hodographs in the lowest 3 km and good tilting of updrafts. Where the winds are more southeasterly, storm relative helicity values through that 0 to 3 km layer will be in the 300 to 400+ m2/s2 range with strong streamwise ingest. Therefore, the tornado threat looks high for any storms that do develop this afternoon, especially in areas farther south and east in the area. With supercells being the most likely storm mode, large hail (2"+) and damaging winds (up to 75 mph) will also be possible, in addition to the tornado threat. Of course, this is all contingent on the atmosphere recovering as models suggest. The tornado watch remains in place until 3 pm for southeastern Iowa where the highest risk resides.

Finally, heavy rainfall will also accompany storms over southern Iowa this afternoon. Portions of south central Iowa are already experiencing flooding issues at this time, and additional rainfall amounts of 1 to 2 inches will exacerbate these conditions. For this reason, the flood watch has been extended through 4 pm.

SHORT TERM /THROUGH SATURDAY/

Issued at 150 PM CDT Thu Jun 11 2026

Storms from today move out late this afternoon and evening as the surface low lifts eastward out of the area. This will pull the cold front through the area putting an end to our severe thunderstorm chances. However, breezy north northwesterly winds are expected behind the surface boundary through at least the afternoon, although these diminish overnight.

Drier conditions develop Friday as surface high pressure spills into the central US. Highs are still expected to be warm in the low to mid 80s, but dewpoints in the 50s should give some reprieve to the humid conditions of recent days. Winds will be light to breezy out of the west, with the strongest gusts around 20 to 25 mph over northern Iowa. Clear skies will be the icing on the cake for what will be a nice break after a wet and active few days.

Unfortunately, this break is fairly short-lived. Another 500 mb trough will dig into the roughly zonal pattern aloft, bringing thunderstorm chances back to the state on Saturday. Higher dewpoints return overnight Friday into Saturday, with instability increasing into the morning hours. A subtle surface boundary will then drop through the state on Saturday morning, providing lift for a few storms in this destabilizing air mass. This front will continue southward through the day Saturday, with more robust thunderstorm development expected as temperatures warm and instability increases ahead of the boundary through the day. For Iowa, the severe risk for Iowa Saturday afternoon will be contingent on how quickly this front progresses, with some more recent guidance (namely the GFS) suggesting the boundary may be through the area by peak heating in the afternoon, while others (ECMWF and NAM) have storms developing during peak heating in southern Iowa. The GEFS-based machine learning guidance is also pushing the severe threat farther south of Iowa. Timing of the front and character of morning convection will be important, and will be interesting to see how high resolution guidance handles this in the coming days. Regardless, the environment ahead of the front on Saturday will be conducive for severe storms with 2000+ J/kg of surface based CAPE and 30 to 40 kts of deep layer shear. All hazards will be possible for any storms that develop mid-day through the afternoon Saturday, just will need to monitor if this threat will reside in Iowa or be shunted southward.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

Issued at 150 PM CDT Thu Jun 11 2026

High pressure fills in again behind the Saturday wave, resulting in mostly dry conditions through Sunday and into the beginning of next week. Temperatures will be milder through this period, with highs in the mid 70s on Sunday and upper 70s on Monday. As we get into the middle of next week, the pattern turns a bit more active again, but there's plenty of time to hash that out in the coming days.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1225 PM CDT Thu Jun 11 2026

Showers and thunderstorms persist over much of central into eastern Iowa today, and will continue through the mid-afternoon before departing the area this evening. Some of these storms may be severe, especially near KOTM where heavy rain, strong winds, hail and even a tornado are possible. MVFR to IFR ceilings are accompanying this shower and storm activity today, but will be moving out this afternoon as well. Breezy north northwesterly winds with gusts up to 35 kts will be possible behind the rain today, but should generally diminish this evening.

DMX WATCHES/WARNINGS/ADVISORIES

Flood Watch until 4 PM CDT this afternoon for IAZ061-062-074- 075-084>086-095>097.