textproduct: Des Moines

KEY MESSAGES

- Another cool and mostly cloudy day today. A few areas of fog and drizzle through mid morning.

- A few areas of fog possible tonight followed by a mild Thursday.

- Rain chances in far southern Iowa Thursday night into Friday and continue to trim NBM PoP south.

DISCUSSION

Issued at 358 AM CST Wed Nov 19 2025

A large area of stratus extends from eastern Nebraska to western Pennsylvania this morning. A ridge of high pressure through Iowa and into the western Great Lakes is driving the low level steering flow of this stratus. The current stratus level wind flow is mostly light easterly across Iowa with some northeast component over southwest Iowa. This flow continues to move stratus into the state and expand it to the southwest into northeast Kansas. The steering flow will turn light northerly this morning and remains around 5 to 10 kts into the afternoon. This will lead to a slow lift of the clouds northward and while some erosion on the southwest edge of the cloud field may occur, central Iowa will remain mostly cloudy today. Cumulus may develop in any clearing areas behind the stratus retreat due to residual low level moisture rising and condensation. Lowered high temperatures further today in response to the stratus with highs in the 40s. The highest confidence of low stratus is over the northeast and could see a repeat of Tuesday and only have a 2 to 4 degree diurnal rise.

A few items in the immediate term is fog and lingering drizzle. Visibilities across most of the forecast area are below 3sm and there have been brief periods of one quarter mile vsbys at times. The lower vsbys are collocated with cloud bases in the 200-300 ft range. This trend should stay status quo over the next several hours, especially due to the stratus in place. A few patches of light drizzle are occurring as well and roughly along the I80 corridor west of Des Moines. Turbulence within the saturated layer remains minimal. Both the fog and drizzle may persist through mid morning in some areas.

Fog could become possible again tonight, especially in any clearing areas and lighter winds across the state. Thursday is expected to be mild with some sunshine. High temperatures in the 50s to low 60s are possible. Continue to monitor the system for the end of the week. The NBM pops continue to be aggressive with precipitation chances into central Iowa. This seems to be largely driven by the GFS and some of its ensemble members of which even half of those are drier. Followed a solution with a more pronounced high pressure system and associated dry air moving into Iowa at this time and that is represented well in the ECMWF/ECMWF ensembles and other deterministics. A mild weekend will follow.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1049 PM CST Tue Nov 18 2025

Widespread low stratus will remain overhead through the morning and into the afternoon across the terminals, which will result in continued IFR and even LIFR categories for the next several hours. These conditions are being amplified by increasing patchy to localized dense fog covering much of central Iowa, where visibilities down to 1-3 miles may occur at times, with highest chances over northern Iowa through the morning before gradually dissipating. Isolated drizzle may also occur at times early on given the abundance of low level saturation along with low cloud bases. Due to uncertainty on the overall timing and coverage of the lower visibilities due to fog, and at times drizzle potential, amendments are expected at times as conditions evolve. Otherwise, winds will be light through the period, gradually turning southerly later in the day.

DMX WATCHES/WARNINGS/ADVISORIES

None.