textproduct: Des Moines

KEY MESSAGES

- Showers lingering early this morning then dissipate around sunrise. Additional shower and storm development possible in eastern Iowa this afternoon.

- More storms possible late Sunday afternoon into the evening, mainly over northwest into north central Iowa. A few strong storms are possible, with wind and hail being the main threats. - Temperatures warm into the 70s today and then nearing 80 on Sunday. Warm temperatures in the 80s continue through the work week with intermittent shower and storm chances.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 312 AM CDT Sat May 23 2026

A ragged, north to south oriented line of scattered showers is currently passing through central Iowa early this morning. This same activity was actually responsible for two separate embedded tornado reports over Nebraska and far western Iowa earlier last evening, but has greatly diminished in organization and intensity since then. Occasional lightning is being observed, but has been sporadic with most of the area only seeing light to moderate rain at this point. Very little instability is left available to this activity, but residual lift will allow for the showers to linger through the next few hours before eventually diminishing later this morning.

The weak boundary and coincident system responsible for last evening and this morning's rain and storms will continue eastward through the upper Midwest today, flipping surface winds to a west northwest direction by mid-day. Drier and slightly cooler air will fill in behind the surface front, although temperatures will still climb into the 70s today. There is still indication that showers and storms will re-develop along the front in eastern Iowa later this afternoon, but this will primarily be outside of our forecast area. Still, those in east central Iowa could see a brief shower or two before the front completely exits the area today.

Weak surface high pressure fills in behind the front tonight into early Sunday, leading to light, variable winds and clearing skies overnight. This high pressure doesn't stick around long though, as southerly return flow on Sunday begins to advect warm and moist air back up into the state. High temperatures will respond accordingly, with most of Iowa expected to near 80 degrees Sunday afternoon. Tightening pressure gradients ahead of the building low pressure out west will lead to breezier conditions on Sunday, mainly over western Iowa where gusts around 20 to 25 mph are expected. Finally, steep lapse rates and increased moisture advection will lead to some shower and thunderstorm potential late Sunday afternoon and evening, primarily over northwestern into north central Iowa.

The instability Sunday afternoon into early evening will be sufficient for strong updrafts, with 1500 to 2000+ J/kg of most unstable CAPE in the afternoon, some of which could be surface based. winds through the layer won't be overly strong, but veering flow in the low levels and slightly increased winds aloft will allow for a modest amount of both speed and directional shear, netting about 30 to 40 kts of 0 to 6 km shear and good turning in the low levels. This environment would support the development of at least a few organized updrafts capable of producing hail, as well as some stronger downburst winds with the DCAPE values of 1000+ J/kg. Fortunately, LCLs will be rather high and low level instability is rather weak, so the tornado threat looks limited, even if storms realize any surface based convection. However, time of day will also likely play a role, with early high resolution guidance not kicking off convection until near or slightly after sunset. After sunset, the low level jet will be ramping up, but instability will also be waning. The storm prediction center has maintained their marginal risk (level 1 of 5) for severe weather over portions of northwest into north central Iowa, which just clips some of our northwest counties. The greatest severe potential with storms on Sunday will be with any storms that can develop late in the afternoon to early evening, with storms then becoming elevated later into the evening hours.

LONG TERM /MONDAY THROUGH FRIDAY/

Issued at 235 PM CDT Fri May 22 2026

A blocking pattern will form for the week and has continued to trend west with each issuance. What this means is Iowa may see increased influence from the eastern trough in the form of height rises and subsidence. A Great Lakes high will reinforce dry air. The upper-level ridge will push temperatures into the 80s. It will be an overall summertime pattern with warm temperatures and diurnally-driven thunderstorms where the moisture axis will reach. Right now, this is most likely in southwest Iowa.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 631 AM CDT Sat May 23 2026

A north to south oriented strip of MVFR cloud cover with a few embedded showers continues eastward through the area today. There is a focused area of clouds less than 1000 ft over northern Iowa on the back (western) edge of this cloud deck, so have included a TEMPO for IFR conditions at KMCW this morning. This cloud deck and showers should move out by mid-day. A brief shower/thunderstorm could occur near KOTM around noon before it completely departs, but have kept as shower chances in TAF for now. Otherwise, light west northwesterly winds and VFR conditions expected through the remainder of this TAF period.

DMX WATCHES/WARNINGS/ADVISORIES

None.