textproduct: Des Moines

KEY MESSAGES

- Patches of transient fog possible tonight.

- Pleasant conditions Wednesday and Thursday.

- A few showers and isolated storms Thursday night.

- Breezy conditions Friday and windy on Saturday.

SHORT TERM /THROUGH THURSDAY/

Issued at 141 PM CDT Tue Oct 6 2026

Trough of low pressure that is stretched across central Minnesota to far southeast South Dakota and into Nebraska, is moving slowly east/southeast. Breezy south to southeast wind has developed ahead of the system over Iowa along with mostly sunny skies. A ribbon of strong theta-e advection has been ongoing over the state today and the lack of any clouds shows just how dry the preexisting air mass was. The breezy winds will subside later this afternoon and into the early evening with the loss of diurnal heating. The aforementioned boundary will settle across the state overnight. Pooling dew points along the boundary along with the wind becoming light could lead to a supportive environment for some transient fog development. Residence time of any fog would be brief and it would dissipate in the wake of the boundary with drier air advecting in.

High pressure ridging will return on Wednesday and will result in another pleasant day across Iowa with highs in the 70s and lighter winds. A few passing cirrus clouds are expected. The area of high pressure will move over Iowa Wednesday night into Thursday. Radiation cooling conditions may form Wednesday night with temperatures likely falling below guidance.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/

Issued at 141 PM CDT Tue Oct 6 2026

Return flow will develop Thursday night as the high pressure system moves into the Ohio Valley while Lee side cyclogenesis begins to occur over Wyoming and Colorado. NBM output for PoPs Thursday night have been inconsistent. Most likely, there will be a few showers and isolated thunderstorms around. Proximity sounding sampling of numerous deterministic models suggest saturation will again be a challenge but even shallow saturation in optimal locations in the profile will lead to free parcel lift and modest convective instability. Friday and Saturday will feature an increasing pressure gradient across the Midwest leading to breezy to gusty conditions on Friday. Windy conditions are possible on Saturday with the combination of the pressure gradient approaching 30 ubars/km over the northwest and mixed layer winds near 40 kts. Temperature advection through the profile will be near neutral so mixing efficiency will be average but not as efficient as with cold to strong cold advection. As discussed yesterday, an upper low descending into the Pacific Northwest this weekend will bring a transition from westerly to southwesterly flow to Iowa late weekend and into early next week. The extended forecast beyond that is quite noisy with below average handling of this upper low. The impacts from another upper low lifting out of the south central CONUS and ingested tropical system this weekend appears to remain to the southeast of the forecast area.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 629 PM CDT Tue Oct 6 2026

Largely VFR conditions are forecast through the TAF window. Fog development is possible overnight and will drift south with a boundary moving through the area. KFOD and KMCW will remain fog free but can't rule out fog induced reductions at KALO, KDSM and KOTM as the fog drifts south with the boundary. Otherwise winds will be light overnight but will start to pick up late Wednesday morning out of the north-northwest staying between 5 and 10 knots.

DMX WATCHES/WARNINGS/ADVISORIES

None.