textproduct: Des Moines

KEY MESSAGES

- Much cooler today through the end of the week with highs in the upper 50s to low 60s. Temperatures tonight reach the mid to upper 30s in northern Iowa with patchy frost possible there.

- Rain chances return late Thursday into Friday.

-Warming trend this weekend with 80s returning by Sunday through early next week.

SHORT TERM /THROUGH TONIGHT/

Issued at 220 AM CDT Tue May 19 2026

The surface low continues to move east across the area with associated rain pushing into eastern Iowa early this morning. While the bulk of the rainfall has come to an end, some wrap around light sprinkles may be possible in northern Iowa through today as the low continues to slide east. Today will be markedly cooler as much cooler air filters in behind the cold front. Temperatures early this morning are in the mid 40s across northwest Iowa with 50s central and southeast Iowa still in the mid 60s. That cooler air northwest will continue to spread across the state today and highs will remain in the upper 50s to low 60s. Winds will also be brisk out of the northwest at 20-30 mph owed to a modestly enhanced pressure gradient across the area from the departing low and incoming high pressure, along with subsidence and cold air advection. Skies clear through the day as high pressure settles across the state. Will clear skies and light wind overnight temperatures are expected to fall off quickly overnight. Low temperatures in northern Iowa will fall to the mid to upper 30s which may result in patchy frost, which would impact those with sensitive plants.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 1250 PM CDT Mon May 18 2026

By Tuesday evening a large surface high pressure area will be building down the northern High Plains and on Tuesday night will settle across Iowa and Minnesota. This will lead to rapidly diminishing winds around sunset Tuesday and much cooler temperatures Tuesday night as winds go light or calm and skies clear out, especially near the Minnesota border closer to the center of the high and where chances for high cirrus clouds are lowest. The result is forecast low temperatures early Wednesday morning in the mid-to- upper 30s in our northern and western counties, but any frost potential will be dependent on skies remaining clear and winds becoming calm. This possibility will be better assessed tonight and tomorrow.

From Wednesday through the end of this week a weak 500 MB low will meander across southwestern Canada, with cyclonic flow extending down across the U.S. Rockies and near Iowa. A series of shortwave impulses moving through the flow will result in a return of rain chances for our forecast area. Initially, on Wednesday, the proximity of the slowly departing surface high pressure area and associated dry air will inhibit any precipitation chances. By Thursday atmospheric moisture and instability will be gradually increasing however, and around Thursday night and Friday the most pronounced 500 MB trough will move overhead and bring higher rain chances (50-70%). In wake of that trough, next weekend, weak subsidence may follow along with weak surface riding, supporting mostly dry weather and much lower rain chances (10-20%). Also of note is a consistent signal for some degree of thermal ridging around Sunday into early next week, especially from the EC and GEM, lending confidence to warmer temperatures at the end of the current 7-day forecast. Climate Prediction Center outlooks also support a likelihood of warmer than normal temperatures heading into next week.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 220 AM CDT Tue May 19 2026

Precipitation is shifting east of the TAF sites with MVFR to IFR stratus settling across the area. A few pockets of LIFR ceilings are possible through this morning. Stratus will last into the afternoon with gradual improvement as coverage diminishes. Winds will also shift to out of the northwest and become breezy with gusts of 20-25+ kts today. Skies clear and winds diminish by 00z.

DMX WATCHES/WARNINGS/ADVISORIES

Flood Watch until 7 AM CDT this morning for IAZ081>083-092>095.