textproduct: Des Moines

KEY MESSAGES

- Scattered showers move northwest to southeast across Iowa overnight.

- Strong to severe thunderstorms overnight Tuesday into Wednesday morning and again Wednesday afternoon.

- Prolonged mild conditions this week and into next week with highs in the upper 70s and low 80s.

SHORT TERM /THROUGH WEDNESDAY/

Issued at 228 PM CDT Mon Jun 15 2026

Tranquil mid-June conditions across Iowa today. Wind has been from the west at around 10 mph with a few passing clouds and temperatures warming into the upper 70s to near 80. Iowa is currently near the base of a board upper level trough across much of the central US, with an embedded PV anomaly across the Dakotas into Minnesota this afternoon. This will swing south this evening and move across Iowa overnight and early Tuesday morning. Scattered showers, and perhaps a few rumbles of thunder, are possible. Model soundings are very dry through the low levels with only modest saturation in the mid levels. With a couple hundred joules of CAPE a few rumbles of thunder are possible but severe weather is not expected.

The rest of Tuesday will be dry with quickly clearing skies. Modest cold air advection paired with weak subsidence and an enhanced pressure gradient will allow for breezy northwest winds, gusting 20-25 mph at times, on Tuesday. Meanwhile, an embedded shortwave within the parent trough will deepen upstream across Montana through the day on Tuesday, swinging through the northern plains on Tuesday night and reaching northern Iowa overnight and early Wednesday morning.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/

Issued at 228 PM CDT Mon Jun 15 2026

Very early Wednesday morning the surface low will make it to northern Iowa, moving roughly the northern half of the state through the morning hours. SPC has added a marginal (level 1 of 5) risk for these storms early Wednesday morning, but noted that a portion of the risk area within Iowa may have a pocket of higher threat to be assessed. As it stands, a robust low level jet (60+ kts) will stretch across the plains and nose into northwest Iowa overnight, pulling moisture into the area before shunting east through the morning. A plume of 1500-2000+ J/kg MUCAPE reaches Iowa with storms likely to move east along the gradient through the morning. There is the potential that storms are able to grow upscale as the move into Iowa and encounter the better instability, fueled by the low level jet as they race east. Additional storm develop is expected along the boundary in southeast Iowa in the afternoon as daytime destabilization increases instability. The primary uncertainty is where this afternoon redevelopment sets up, hinging heavily on the path and strength of the early morning storms and associated outflow boundaries.

Strong environmental winds are expected Wednesday late afternoon into evening as storms push east with stronger subsidence, cold air advection, and a tight pressure gradient on the back side of the system as it departs. Soundings indicate 30-45+ kts through the mixed layer behind the departing system on Wednesday which may translate to 30-40+ mph gusts at the surface, especially across northern into central Iowa. Northwest flow keeps the area seasonably cool through the end of the week and into next week with highs in the upper 70s to low 80s. There are also repeated precipitation chances through the rest of the forecast period. A weak wave will likley bring additional showers and thunderstorms to the area on Thursday. Then a more robust system develops across the midwest on Saturday and Sunday. As we look ahead into next week the CPC notes continued cooler than average and higher precipitation than average through the 8-14 day outlook.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1051 PM CDT Mon Jun 15 2026

TAFs are forecast to remain VFR; however light rain showers are diving southeast into the area and will bringing brief showers or storms before quickly passing. KFOD and KMCW will likely see light rain at the start of the 06Z TAF window before dissipating followed by the remaining sites over the next few hours. Guidance suggests that sites will remain VFR but can't rule out a momentary drop into categorical MVFR. Once convection wanes after 12Z, post-frontal northwesterly winds progged to develop and persist through the remainder of the TAF, gusting to 25kts in the east. Winds are forecast to diminish after 00Z to light and variable.

DMX WATCHES/WARNINGS/ADVISORIES

None.