textproduct: Des Moines

KEY MESSAGES

- Warm and breezy today, but with a cold front pushing through this afternoon and evening. A few strong to severe thunderstorms will be possible along the front this evening in southeast Iowa.

- Breezy winds and potential light showers behind the cold front this evening over north-central to central Iowa, lingering south into early Tuesday morning.

- Cooler weather from Tuesday into Thursday, with another frost/freeze possible in parts of Iowa into Wednesday morning.

SHORT TERM /THROUGH TUESDAY/

Issued at 359 AM CDT Mon May 4 2026

Mild and dry conditions persist across Iowa early this morning, with light south/southwesterly winds keeping most areas on the warmer side in the upper 40s to low 50s, despite mostly clear skies across the area. Upper level clouds however are noted further north into Minnesota per satellite imagery, given the presence of moisture in this layer, which will gradually shift southward into Iowa later today. Through the rest of this morning, southwest flow and increasing theta-e advection will spread into Iowa, especially across the south. Temperatures as a result will easily soar through the 70s over northern to north central Iowa, and into the low 80s for much of central Iowa by this afternoon, paired with dewpoints in the 40s to low 50s, highest south. The main feature of focus today otherwise will be a defined cold front, currently seen draped across southern North Dakota into northern Minnesota that is expected to make its way into Iowa later today. This feature is associated with a deepening area of strong low pressure over southern Ontario, which will continue to depart slowly eastward through today. With the influence of this system felt over northern Iowa this morning in particular, an area of localized strong 850mb winds over this area may mix down occasionally, with gusts up to 25-35 mph at times before decreasing by the afternoon. Regarding timing of the surface front across Iowa today, expectations per latest guidance has this boundary arriving into northwest Iowa around 11am-12pm, drifting south/southeast through about 9-10 pm when it will then exit the state. As this front passes overhead, dry conditions are expected to largely persist through the afternoon, given the presence of a pronounced layer of near surface dry air and capping overhead. By the early evening though, showers and storms are expected to develop along and ahead of the boundary, particularly over southeast Iowa. However, trends continue to indicate the front into northern Missouri before storms even develop, which is something that will need to continue being monitored. Overall, environmental parameters into southeast Iowa are characterized by instability values around 1500 J/kg, shear of 35-40 knots, along with steep lapse rates around 8 C/km and DCAPE values around 1000-1200 J/kg, which would point to favorable storm development and maturity to produce large hail and even more so damaging winds, especially considering the aforementioned low level dry air that is still indicated per soundings to be overhead. This overall risk is conditional though, given lingering uncertainty on the exact location of the front this evening and overall moisture availability. The Marginal Risk remains over the southeast half of Iowa per SPC to highlight this remaining potential.

Outside of the potential risk for storms, there remains a signal for winds to pick up behind the surface cold front as the elevated boundary follows it, with models such as the HRRR showing brisk winds gusting to 25-35 mph by late in the afternoon and through the evening. CAMS continue to indicate a swath of light reflectivities in relation to the elevated front passing through into the evening which will keep lingering chances for light rain showers in the forecast until early Tuesday morning. Very little impact is expected as any QPF output would be very light. Temperatures behind the surface front will fall through the evening and overnight, with northerly flow advecting cooler air across the state. Overnight lows are expected to fall into the upper 30s to upper 40s, coldest over northern Iowa. A broad area of high pressure will spread across the Midwest region Tuesday, with drier and cooler air remaining overhead. Winds out of the northwest will be common, along with highs topping out in the upper 50s to low 60s, warmest south.

LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/

Issued at 359 AM CDT Mon May 4 2026

The overall pattern through midweek changes little, with broad troughing across the Midwest and weak but broad high pressure over the area keeping conditions on the dry and cool side. Potential for frost/freeze is increasing mainly over northern to north central Iowa Tuesday night/Wednesday, with headlines certainly possible during this time but will need to monitor potential lingering clouds and light winds over the area that would overall limit frost formation from occurring. By Thursday, this trough finally begins to depart to the east, with an area of mid-level ridging to the west. A very low potential (<15%) for light rain is signaled over northeast Iowa later in the day with another shortwave passing southeast within the larger flow, though the better forcing and moisture is confined further east into WI at this time. The region will otherwise experience gradually warming conditions as a result of low level flow returning back from the west/southwest that will lead to highs back into the 60s through Friday. Low rain chances (<20%) return again over southern Iowa Friday, with otherwise dry and warmer conditions largely remaining into the start of the upcoming weekend.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1042 PM CDT Sun May 3 2026

VFR conditions prevail through much of the TAF period. Light and variable winds this morning will increase out of the southwest after sunrise. A front dropping north to south through the area will lead to increased winds and changing directions through the day. Winds become westerly just ahead of the front, then northerly behind. Winds will generally gust to around 20 to 25 kts, with sporadically higher gusts near 30 kts possible. A few showers and/or thunderstorms are possible along the front in the late afternoon and evening, but this threat looks to be primarily over KOTM and southeast. Winds remain breezy into the evening, before diminishing overnight.

DMX WATCHES/WARNINGS/ADVISORIES

None.