textproduct: Des Moines

KEY MESSAGES

- Few lingering showers, isolated non-severe storms, in northern Iowa this afternoon. Some continue to produce efficient rainfall.

- There is a low chance for a few severe storms this evening into tonight, but the question is if storms can develop. If storms do develop, gusty winds, hail, and locally heavy rainfall will be the main threats.

- Monday is favoring drier conditions with capping in place to limit if not prevent storms. However, similar to Sunday, if storms can develop, a few severe storms with hail or gusty winds are possible.

- High pressure drifts southward through the Great Lakes into the Ohio Valley, which pushes rain and storm chances west of the state Tuesday and Wednesday and perhaps Thursday. Highs above normal in the 80s.

SHORT TERM /THROUGH TUESDAY/

Issued at 253 PM CDT Sun May 31 2026

Morning rainfall has continued to slowly lift northward with occasional storms/lightning. Some areas, especially towards northern Blackhawk into southern Bremer Counties have seen some decent rainfall of at least 1" where showers/storms have repeatedly tracked, but isolated locations of 1-2"+. The bulk of the rainfall activity has largely ended for this afternoon in that area, but will certainly be keeping an eye on this area and similarly central Butler County for any hydro issues that may occur should any additional storms develop and track over this area tonight.

On that note, cloud cover and the rainfall has kept conditions cooler in northern into portions of northeast Iowa. Meanwhile, conditions have started to clear and warm in western into southern Iowa. While in the north and northeast temperatures are in the 60s, in the west and south, temperatures have warmed into the 80s with dew points largely in the 50s-60s making it feel muggy. As has been discussed over the last several days and would be expected given the warm, humid conditions noted in areas that have also seen sunshine, additional storm development is the main forecast challenge through the evening. With minimal forcing in Iowa and a cap seen in forecast soundings with mid level warm and dry air, storm development is not a certainty. We are starting to see a cu field develop in the south and west but largely not expecting any storms to take off and sustain before 00Z. The area to watch is back in eastern Nebraska where a boundary appears to be stalled out. This is the most likely location for storms to develop if they can break through the cap, which per soundings, is not as stout as further east. Instability is plentiful but shear remains weaker making it more difficult for storms to maintain. CAMs have started to come into some agree with storms firing in eastern Nebraska between 00-3Z and moving east into Iowa after, maybe reaching our western area around 06Z but would be on a weakening trend so confidence in eastern extent (should these storms actually develop) is not high. Timing and the expected weakening trend make severe storms unlikely overall, but a stronger storm could have some hail or gusty winds. Pwats do remain over 1.5" so will continue to see the potential for locally heavy rainfall with any storms that do develop and track into our area. Storm motions remain slow, though albeit a little faster than say yesterday, around 20 knots. QPF guidance is in better agreement with totals over 1" in eastern Nebraska/far western Iowa, but should storms maintain, could see some localized 1-2"+, maybe 2-3" on the high end, but this high end does not seem likely given the questions on storm maintenance.

Upper lows over Montana and just off the Northeast U.S. coast will keep upper riding in place to start the new work week. After a dry morning, some weak shortwave energy may move in later Monday afternoon into Monday evening but QPF fields are sporadic in bringing much of any QPF into our area (largely to our west) which aligns with the better moisture to our south and then west later Monday into early Tuesday morning. CAMs have varying ideas of kicking of storms again Monday afternoon and evening. Global models (NAM, GFS) have also started a drying trend later Monday. Not too dissimilar from today, if a storm could develop, it would be in an environment characterized by ample instability but with varying ideas in the amount of shear present with the GFS/NAM around 30-40 knots and the Euro closer to 25-30 and mostly offset with the higher shear values from the higher instability values. This to say should a storm get going, it could become strong to severe with hail or gusty winds, but trends are certainly on the drier side Monday with plenty of mid to upper level dry air capping off the atmosphere making it difficult for storms to develop. The potential thing to watch, however, is what occurs further west in Nebraska tomorrow night and if any storms can maintain into Tuesday morning. CAMs and global models remain in decent agreement that activity fades before it gets into central Iowa (and even into Iowa for the most part). Thus, we keep another conditional threat for storms Monday but even more so than tonight, most areas may remain dry.

LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/

Issued at 253 PM CDT Sun May 31 2026

Warm conditions continue this week with highs in the 80s. A Great Lakes high looks to keep conditions dry Tuesday into Wednesday with storm chances returning later in the week as the upper ridge finally breaks down. By the end of the week, temperatures may warm further as southwest flow kicks in with additional storm chances into the weekend.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1053 PM CDT Sun May 31 2026

A scattered line of storms is beginning to develop in eastern Nebraska and will move east into western Iowa overnight. Current expectations are for activity to diminish before reaching TAF sites and have not included any mentions, however will need to monitor for possible later adjustments. Patchy fog development remains a possibility on Monday morning, however uncertainty with cloud cover and degree of cooling was too high to include at this time. Light wind under 10 kts will be from the ESE this evening, becoming variable overnight, then from the ENE on Monday.

DMX WATCHES/WARNINGS/ADVISORIES

None.