textproduct: Des Moines

KEY MESSAGES

- Cool with highs in the 60s through Friday.

- Spotty showers through the day today, then more widespread showers and a few rumbles of thunder on Friday.

- Warming this weekend with highs in the 70s to low 80s. Then mid to upper 80s return by next week.

SHORT TERM /THROUGH FRIDAY/

Issued at 154 AM CDT Thu May 21 2026

High clouds continue to stream into the area overnight, along with spotty showers in far southwest Iowa early this morning. This is due to a long wave trough setup across the western US, with an associated surface low across north Texas. Meanwhile, the surface high is still parked northeast of the area with dry air eating away at any attempt at moisture transport into the area. As the southern surface low lifts north today it will be shunted east by the high pressure and dry air will continue to limit better saturation across Iowa. This will result in very spotty, light showers today with much of the area dry. That high pressure will also continue to advect cool air in the area with highs today in the low 60s once again (this is 10-15 degrees below average for this time of year).

Overnight tonight the upper level trough will finally swing into the midwest, bringing with it better upper level support. Profiles begin to saturate, however mid level moisture still struggles with the better plume of moisture transport still offset east of the area. Even so, increase low level moisture should help support more widespread showers across Iowa on Friday, although with lacking mid level moisture it will not be a washout. There is weak instability into the area as the surface low lifts north of the area which may allow for a few rumbles of thunder, but severe weather is not anticipated. A stray shower could linger into Saturday but thermal ridging builds and kicks the upper level trough east. This kicks off a warming trend through the weekend and next week, described below.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Issued at 146 PM CDT Wed May 20 2026

Thermal ridging builds Saturday into Sunday with temperatures warming through the 70s to near 80. While the current forecast for Sunday is dry, an isolated shower is possible as a shortwave trough ejects across the state and into Minnesota. As mentioned in the previous discussion, an upper-level low in the southern CONUS will get trapped within the ridge early next week. Behind it will be deepening troughing, featuring two closed features, one in the PNW and one in southern California. The pattern favors warming temperatures with the advection of the thermal ridge, but that first trapped feature leaves some question marks early on. The solution this period continues to favor a due- north ejection into Iowa as early as Tuesday night. Temperatures increase and precipitation chances broaden in the second half of next week. Warm, active weather is favored with the western CONUS troughing and the next best chance of precipitation will arrive when the southern feature is flung into the Plains by its northern counterpart. Regional ridging persists into next weekend.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1033 PM CDT Wed May 20 2026

VFR conditions ongoing and expected to continue through much of the TAF period. Mid-level clouds between roughly 04kft and 10kft expected through the daytime with lowering CIGs in the west towards the end of the TAF period. Winds light and variable to out of the northeast to start, becoming out of the east or southeast into Thursday morning and increasing, but generally staying around 10-15 knots. A few low-end (20%) rain chances in southwest to south central Iowa overnight. Higher rain chances move in late Thursday night but towards the end or after this TAF period for TAF sites, and will address in future issuances.

DMX WATCHES/WARNINGS/ADVISORIES

None.