textproduct: Des Moines

KEY MESSAGES

- Slightly cooler today followed by a warming trend through the week. High temperatures will remain above seasonal normals.

- The forecast is dry through the work week, with rain chances returning sometime next weekend.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 247 AM CDT Mon Oct 19 2026

The transition to weak southwest flow aloft has begun and this has led to high level cirrus arriving into the Midwest. A slight cooling in the thermal profile at and below 850 mb has occurred over the past 24 hrs as the upper level ridging was flattened prior during the transition. A weakening of the pressure gradient and mixed layer winds will also be noticeable today. The net result of all of this is a few passing clouds and slightly cooler high temperatures. Upper low pressure diving south along the Pacific coast along with sub- tropical high pressure building into southern Texas, will combine to start to build upper ridging to the west of the state on Tuesday with mid-level diffluence over Iowa. Mixed layer winds will increase on Tuesday with diurnal wind gusts of 15 to 20 mph possible. High temperatures on Tuesday will be a few degrees warmer that today with readings in the 60s to near 70.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

Issued at 103 PM CDT Sun Oct 18 2026

Between Wednesday and Wednesday night the weakened 500 MB trough axis will finally cross Iowa, bringing somewhat thicker mid/high level clouds. However, the trough will be largely washed out by that time and a deep near-surface dry layer will persist, once again reducing any rain chances. Thereafter, a high-amplitude ridging pattern will build across the central U.S., with the axis stretching all the way from Mexico up to Hudson Bay by Thursday evening. This will maintain dry and notably warmer weather at the end of the work week. Both Thursday and Friday high temperatures will likely range in the mid to upper 70s, and a few areas could even touch 80 degrees.

By Friday, even as the 500 MB ridge axis moves over Iowa, a deep trough will build over the western U.S. and subsequently slide northeastward into the Upper Midwest, shunting the preceding ridge southeastward and bringing a return of rain chances followed eventually by a surface trough/cool front through Iowa. While this general scenario is likely to occur, long-range models still vary considerably in the details of the evolution, timing and magnitude of any rain chances, strength of the surface trough, etc. As such, persistent low (20-30%) rain chances are forecast next weekend but it is likely these will eventually narrow to a shorter period of higher POPs as confidence in timing increases later this week.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1215 PM CDT Mon Oct 19 2026

VFR conditions prevail with light winds out of the south to southeast. Occasional high clouds will pass through during the day today, with skies clearing out overnight. There is some signal for patchy, shallow fog early tomorrow morning (9z to 12z), mainly near KMCW, but probabilities are too low to include in TAFs at this time.

DMX WATCHES/WARNINGS/ADVISORIES

None.