textproduct: Des Moines

KEY MESSAGES

- Scattered showers and thunderstorms Thursday afternoon ahead of a severe line expected to pass across the state late Thursday afternoon and evening. Damaging wind is the primary hazard, however large hail and tornadoes are possible (primarily with initial storm development west).

- Cooler Friday through the weekend with showers and thunderstorms possible Saturday and Sunday.

SHORT TERM /THROUGH FRIDAY/

Issued at 133 PM CDT Wed Apr 22 2026

A cluster of thunderstorms in northwest Iowa early this morning fizzled out as it move across north central Iowa through midday. Conditions cleared out quickly behind. Southerly flow with theta e advection into the area persisted the rest of the day ahead of an approaching surface low across western Montana this afternoon. Drier air is in place west with deep mixing this afternoon, resulting in wind gusts of 20-25+ mph through the afternoon north and west. Winds begin to come down after sunset as the nighttime inversion sets up, however it is not super deep and winds are not expected to completely drop off overnight.

Deep moisture transport increases across the area on Thursday as the surface low approaches the area. Scattered showers and thunderstorms will increase across the area by early afternoon with this increased moisture and boar ascent ahead of the boundary. The surface cold front then sweeps across the area from west (around 21z) to central (00-02z) and exiting east (04-05z). Better forcing along the frontal boundary will allow for more robust convection and will hold the severe potential for the day. Expect initial discrete storm developing along the boundary in western Iowa to quickly grow upscale into a linear complex. A plume of 1000-1500 J/kg MLCAPE will be in place along with shear around 40 kts. It is important to note that the shear is largely parallel to the line and should mitigate much of the tornado potential along the line of convection. Initially discrete cells in west/southwest Iowa may have a brief window with higher tornado potential, especially given curved low level hodographs. The Creston sounding indicates around 200 m2/s2 0-1km SRH around 21-23z. There is also question as to how surface based these storms will be, and therefore able to take advantage of the low level helicity. With several hours of sub- severe showers and thunderstorms ahead of the main line soundings are fairly saturated in the low levels as the main forcing mechanism comes through and enhances convection.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Issued at 133 PM CDT Wed Apr 22 2026

Cooler air behind the cold front leaves highs Friday in the 60s and these will hang around through the weekend and much of next week. A deep trough will remained parked across Alberta and Saskatchewan with embedded wave rounding the base and moving across the midwest through the weekend. The first is fairly weak and will bring a chance for rain on Saturday. Then, a more robust embedded wave will eject east and move across Iowa Sunday into Monday. A plume of instability with this wave lifts through the plains, but at this time does not quite make it to Iowa late Sunday. Adjustments to the track could result in adjustments to local severe impacts and will monitor closely as the event nears.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1059 PM CDT Wed Apr 22 2026

Patchy MVFR stratus has moved into central Iowa tonight, leading to occasional flight restrictions at KDSM, KOTM, and KFOD through the morning hours. Light rain showers/drizzle will move in later in the morning, leading to IFR conditions. Showers/drizzle will persist into the afternoon hours, then storms develop along a roughly north/south oriented front moving through all sites into the late afternoon and evening, before departing toward the end of the TAF period. Winds will also be breezy out of the south tomorrow.

DMX WATCHES/WARNINGS/ADVISORIES

None.