textproduct: Des Moines

KEY MESSAGES

- A Wind Advisory remains in effect over much of Iowa through sunrise, and slightly later for northeast Iowa, with expected gusts over 40-45 mph.

- Much colder today with highs in the 30s and similar values through Thanksgiving with dry weather expected.

- Increasing confidence for impactful snow accumulation later Friday through Saturday, ending overnight Saturday night. Impacts to travel are increasingly likely.

DISCUSSION

Issued at 408 AM CST Wed Nov 26 2025

Windy conditions remain across much of Iowa early this morning as the strong low pressure system, currently centered over Wisconsin with its eastern fringes still covering Iowa as noted by the very tight pressure gradient, slowly departs northeastward. This gradient, along with strong cold air advection mixing down to the surface exceeded expectations for gusts last night into early this morning, with several sites having maximum brief periods of gusts up to 50-55+ mph, where Lamoni and Des Moines, for example, hit 61 mph from these synoptic winds, which are quite impressive for being synoptically driven. This low pressure is expected to continue tracking northeastward through this morning out of the region, with winds still expected to remain Advisory Level at least until around sunrise for most locations, and lingering a bit longer to the east/northeast until late morning, with the Wind Advisory remaining in effect for the impacted areas. In terms of snow, widespread flurries over northern into central Iowa early on have become very isolated, with very minimal accumulations seen per webcams across the area. Light returns on radar indicate that some additional isolated flurries may occur at times over the next few hours, then ending as the dry and cold air mass settles over the region. High temperatures for today will be noticeably cooler, with expected values only reaching into the 30s and cloud cover decreases, while winds continue to gradually decrease from west to east. Mostly clear skies overnight tonight with remaining northwest flow will allow temperatures to fall into the upper teens to 20s. Large scale ridging with northwesterly flow remains over the Midwest for Thanksgiving, which will keep conditions on the quiet side but chilly, with highs expected in the upper 20s to 30s under mostly sunny skies.

Looking at the current guidance over the northwestern CONUS shows a shortwave trough late Thursday into Friday gradually tracking southeast across Colorado and the Dakotas, which continues to be of growing interest to many as this feature will arrive into the Midwest Friday into Saturday, leading to an increasing potential for widespread winter weather impacts. Latest trends are showing the developing surface low pressure system occurring east of the Rockies Friday morning, then dropping generally south of Iowa, though the associated mid-level feature gradually moves into Iowa into Saturday. Just ahead of this system into Iowa, a notable push in theta-a advection from low level southwest flow and increased forcing is expected. In general, the onset of initial precipitation looks to be slightly slower on arrival than what some of the earlier guidance was showing, with precipitation not expected until Friday evening as the front lifts into Iowa. Overall, Iowa generally will be in the cool sector despite the warm air advection warming temps above freezing into Saturday over southern to south-central Iowa, so precipitation may still fall as a wintry mix over these areas at times. Otherwise, snow will be the primary form of precipitation Friday and Saturday, with the highest chances (70-90%) for snowfall arriving Friday evening and especially Saturday when the low pressure system impacting the region deepens, with Iowa in the deformation zone. Latest ensemble guidance remains fairly consistent with the previous discussion in terms of potential probabilities for higher-end total snow accumulations over Iowa, though look to even be bit higher in overall probabilities. Specifically, northeastern portions of the state have a 90% or higher chance for 4+ inches of snow, with 50% or higher values north of the I-80 corridor, and lesser chances further south to southwest where the rain/snow chances are introduced Saturday. Given this is still a few days out yet, exact snow amounts are still more certain and will really depend on the overall evolution of this system, where any possible shift in track would lead to rather significant changes. The key takeaway is that travel impacts are increasingly likely Friday evening but especially Saturday, so please keep a close eye for updates and plan accordingly as travel impacts are expected to occur.

Lingering snow looks to gradually diminish into Sunday, when Canadian high pressure looks to drop in behind the departing system, with dry conditions returning to end the weekend into early next week. Temperatures will take a further plunge to start the month of December, with average highs for much of next week in the teens to 20s and lows in the single digits and even near to below zero in some areas over northern Iowa. It's pretty safe to say that the cold season is officially here to stay for awhile.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1120 AM CST Wed Nov 26 2025

Winds remain breezy across Iowa with gusts of 35-40 kts at midday. These will gradually diminish through the afternoon and fall off after 00z. While cloud cover has cleared out over much of the state, KALO is on the far edge of the MVFR deck. Expect that this will slide east within an hour or so. VFR conditions prevail through the rest of the period.

DMX WATCHES/WARNINGS/ADVISORIES

None.