textproduct: Des Moines

KEY MESSAGES

-Areas of patchy fog possible Thursday morning across northern Iowa. Another warm and dry afternoon with highs once again in the 70s.

-Breezy conditions develop Friday and Saturday, especially in northern and western Iowa. Somewhat elevated fire weather concerns may develop during this time.

-Rain and relatively cooler temperatures return to northwestern Iowa later this weekend and the remainder of the area early next week.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 318 AM CDT Thu Oct 22 2026

Thursday Morning

We kick off the fourth Thursday of October with very similar conditions to previous nights. The stagnant high pressure that has been locked in place over the Great Lakes will continue to stay put today continuing to usher in south to southeasterly winds. This has brought continuous dry air into the region and kept things mostly calm.

The main challenge this morning will be patchy fog in the same areas where fog has been present over the last few nights. Dense fog is not expected as we continue to lack moisture but due to clear skies, calm winds, a few spots could see some shallow fog- especially in low lying areas and along river river fronts. Fog should burn off shortly after sunrise, and we will be treated once again to an above-average day with mostly sunny skies.

Friday

As we take a look at large scale features, a West Coast low pressure system is expected to come ashore over California later Thursday. It is expected to track northeast and push over the rockies. As this occurs, pressure gradients are expected to tighten across the plains. Winds are expected to increase out of the south 15-20 mph with gusts reaching up to 25 mph and pushing 35 mph in northwest Iowa. This will continue to support the warming trend and could even lead to an elevated fire risk, especially in western and northwest Iowa. The good thing that will be working for us, is that relative humidity values will be in the 30 to 40% range. As the pressure gradient strengthens out west and a strengthening 850mb LLJ, moisture will be brought across portions of northern Nebraska. Showers may develop across the nose of the LLJ but should stay west of central Iowa. So in summary, Friday is shaping up to be another warm and breezy day with highs once again in the 70s.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 101 PM CDT Wed Oct 21 2026

By Saturday morning a southern stream 500 MB low/trough will be centered somewhere near the California/Arizona border. It will then drift slowly east northeastward toward the central U.S. over the weekend and into early next week. By Monday evening it should be located somewhere roughly around Nebraska, but by that time a second 500 MB cyclone will have come ashore over the northwestern CONUS. As these two systems interact with each other the details of their evolution become more uncertain, but by Saturday night the surface trough discussed in the SHORT TERM section above should be pushed across the Dakotas and lie in an orientation parallel to the steering flow, roughly from the central High Plains northeastward near the Iowa/Minnesota border and into the upper Great Lakes. Frontogenetical forcing associated with this increasingly baroclinic zone, beneath modest but broad forcing for ascent aloft, will support increasing rain potential near the boundary as we progress through the weekend. Most of this potential will initially lie north and west of our area, but POPs are introduced for our northwestern counties beginning Saturday night and continuing through Sunday night. The boundary/swath of rain will be slow to progress any farther into Iowa until the main system/s move through sometime between Monday and Tuesday. Given this overall scenario, unseasonably warm conditions in place late this week will continue through Saturday, with the approaching trough/frontal zone/rain swath remaining northwest of Iowa during that time, then be shunted steadily southeastward Sunday and Monday, with daily highs likely more in the 50s and 60s by Tuesday and Wednesday of next week.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1044 PM CDT Wed Oct 21 2026

Main aviation challenge remains whether fog will form and to what extent. Widespread fog seems quite unlikely; however, patchy, shallow fog in low lying areas remains possible over northern Iowa so have transitioned to TEMPO groups at both MCW and FOD. Otherwise, winds will be light to calm overnight and increase to between 4 to 9 knots by Thursday afternoon as VFR conditions prevail.

DMX WATCHES/WARNINGS/ADVISORIES

None.