textproduct: Des Moines

KEY MESSAGES

- Rain continues over western into north central Iowa this morning. Occasional shower and storm chances persist over western into central Iowa today into tonight.

- Breezy conditions today, primarily over northwestern Iowa where wind gusts up to 35 mph are possible.

- Additional shower and storm chances possible east on Saturday.

- Temperatures in the upper 60s to low 70s Today and 70s on Saturday, followed by highs in the 80s for the remainder of the forecast.

SHORT TERM /THROUGH SATURDAY/

Issued at 245 AM CDT Fri May 22 2026

Warm, moist air advecting in at the mid-levels ahead of an approaching trough to our west has produced an area of moderate to occasionally heavy rainfall over western into north central Iowa early this morning. Rain has remained as just showers so far, with little in the way of lightning. This activity should continue to lift north and east out of the state through mid-morning.

Today, easterly surface flow will begin to flip to more southeasterly as a weak surface reflection develops to our northwest. This surface low pressure will continue northeastward with the parent wave aloft, never actually entering the state. However, a north-south oriented boundary will trail behind it, entering western Iowa today and drifting eastward through the state tonight into Saturday. Convergence along this boundary, as well as increasing moisture out ahead of it, will lead to scattered shower and even some storm development primarily over western into central Iowa later this evening and into the overnight. Instability and wind shear in our forecast area will be meager (< 1000 J/kg and < 30 kts, respectively) by the time storms arrive, so severe weather is not anticipated this evening. That said, slightly better instability just to our west could result in a few stronger storms over eastern Nebraska into western Iowa. This slightly more unstable environment has prompted the Storm Prediction Center to include a marginal risk (level 1 of 5) for severe weather over these areas, with the main risks being hail and wind.

This boundary continues to meander eastward into Saturday, although the shower/storm activity will be waning Saturday morning. That said, as daytime heating increases instability out ahead of the boundary, we may see a resurgence in showers and storms while the boundary is over east central Iowa Saturday afternoon. By this time, convergence is very weak, but may be just enough to take advantage of the instability present. Again, the risk for severe storms will be low, but a few rumbles of thunder are still possible before the front finally departs into eastern Iowa Saturday evening.

Beyond precipitation chances, we'll see temperatures climb back near 70 today, then into the mid-70s by Saturday. Tightened pressure gradients near the deepening low will lead to breezier conditions today, primarily over northwestern Iowa where gusts could near 35 mph at times this afternoon. Winds are then lighter on Saturday as pressure gradients relax again.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/

Issued at 223 PM CDT Thu May 21 2026

Mean troughing will continue into the weekend, which keeps the chance of precipitation around at times. Saturday afternoon has trended slightly wetter in the east. This is due to the front from overnight lingering there, and it will have a narrow axis of instability to work with. The highest impact will be lightning, but coverage will be sparse and transient. The thermal ridge will continue to arrive from the west Sunday, but will also be accompanied by more moisture, meaning there will be another chance of showers and storms in the late afternoon and overnight.

In the long term, western CONUS troughing in still favored, but with a more western shift. This centers the eventual blocking pattern over the Plains. There still looks to be a leading embedded closed low in the ridge and it will eventually eject northward into the upper Midwest. The northern stream component of the trough still looks to be a dominant, stagnant feature, churning out segments of energy from the southern stream component. This means that lots of synoptic energy is in play next week, making for a summertime pattern of warm temperatures in the 80s paired with frequent shower and thunderstorm chances at peak heating.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1241 PM CDT Fri May 22 2026

MVFR cigs are focusing into western Iowa in the short term. A line of showers and low chance of thunderstorms will move across the area after 00z, highest confidence in precipitation reaching KFOD and KMCW. Rain will gradually erode after 06z, leaving uncertainty for remaining terminals. What can be said MVFR cigs will return and will return to VFR after the wind shift passes.

DMX WATCHES/WARNINGS/ADVISORIES

None.