textproduct: Des Moines

KEY MESSAGES

- Additional storms are expected to continue developing this afternoon ahead of a cold front with hail, tornadoes, and strong wind potential.

- Locally heavy rainfall could lead to isolated flash flooding with this risk highest in urban areas.

- Cooler, blustery on Saturday. A bit milder, less wind on Sunday.

- Increases chances for rainfall and storms mid into late next week.

SHORT TERM /THROUGH SATURDAY/

Issued at 257 PM CDT Fri Apr 3 2026

Lingering showers and weak storms remain largely over the far northeastern portion of Iowa this afternoon, with the initial wave of convection as the low level warm air advection lifts northward. At the surface, analysis of features shows the surface low pressure system centered over eastern Kansas into northwestern Missouri, with the associated cold front over southwestern Iowa/southeastern Kansas, where showers and storms have begun to develop as of 2pm. Further south, the warm front is slowly lifting north through Missouri, which is expected to arrive into far southern Iowa in the next few hours per latest model trends. With the warm front into southern Iowa and the cold front moving across western Iowa later this afternoon, the expectation is for a line of storms to develop ahead of the cold front from north to south and push eastward across the state. Over southern Iowa, temperatures are expected to reach into the 60s, along with dewpoints in the upper 50s to low 60s where the warm sector will be located. MUCAPE values increasing around 1500 J/kg, along with lapse rates around 7-7.5 C/km and shear values increasing around 40 knots will allow for storms to grow upscale in nature, allowing for the higher potential for severe storms. While the primary hazards are damaging winds and hail, there remains some potential for a few tornadoes, as some clearing over southern Iowa has occurred in a few locations, though cloud cover is still largely overhead. Model soundings continue to indicate curving hodographs and SRH values in the 0-1 km layer around 300 m2/s2, though drops off dramatically in the 1-3 layer around 25-50 m2/s2. Also, the elevated warm layer aloft suggest that storms may remain elevated, before the cold front arrives. Will be monitoring trends very closely over the next several hours. Given the potential though, a Tornado Watch has been issued by the SPC for far southern Iowa until 10pm. Further north into central to northern Iowa, storms are expected to remain more linear in mode ahead of the passing cold front, with damaging winds and hail the main threats through the evening.

Regarding rainfall over the forecast area for the rest of today, the notable increase in moisture transport across the eastern half of Iowa in the low to mid levels will result in PWATS to increase around 1.25-1.50 overhead. Model trends continue to point to highest rainfall amounts over east/northeast Iowa where the heavier rainfall totals over the last few days have already occurred, where soil moisture profiles at this point are in the 90th percentile across northern and eastern Iowa. With an additional 1-2+ inches possible over these areas through this evening, continued river rises is expected, along with the potential for flash flooding.

Into Saturday morning, the system will continue to lift northeast into Wisconsin. As the pressure gradient tightens overhead, with increasing northwest flow and associated cold air advection pushes across the region, winds are expected to increase overhead. Gusts up to 20-30 mph are expected for much of the day, especially over northern Iowa up to 35 mph. Highs are expected to remain on the cooler side in the 40s and even low 50s in far southern Iowa. There remains a low chance for light rain/snow showers mainly over northern Iowa, but any accumulations would be minimal at this time.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/

Issued at 257 PM CDT Fri Apr 3 2026

Dry conditions are expected to remain Sunday as a large area of surface high pressure descends into the western parts of the Central Plains. In the mid-levels, a large area of ridging builds over the Pacific Northwest, which will keep northwest flow into Iowa. A weak shortwave sinks southeast across the Upper Midwest within this flow pattern, with the bulk of forcing and moisture expected at this time to remain north and east out of Iowa. Into the start of the next work week, the ridge starts to break down, becoming more zonal into midweek. A few areas of high pressure drops southeast into the Midwest Monday and again Tuesday, before moving out of the state later in the day. Weak upper level features however early in the week try to bring some low end precipitation chances in the state. Will see winds shifting southerly/southwesterly behind this departing feature, especially into Tuesday evening, which will lead to the distribution of warmer air northward into Iowa by Wednesday. At this point, the pattern is signaled to turn more active as a surface low develops over the Northern Plains, with a frontal boundary entering into the region late Wednesday/Thursday, leading to the start of another period of active weather through late week.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1254 PM CDT Fri Apr 3 2026

Areas of thunderstorms continue to lift across Iowa into the afternoon, impacting KDSM and especially at KALO over the next few hours, with periods of rain showers otherwise over the northern terminals. The expectation remains for additional showers and thunderstorms to develop ahead of a cold front that will track eastward across Iowa through the evening. Kept thunderstorm mentions at most of the terminals during this timeframe in PROB30 groups as exact timing and coverage remain on the lower end of confidence at this time. Trends will continue to be monitored, with amendments made as needed. Ceilings are expected to remain low, with largely IFR and even MVFR as periods of lower visibilities are also expected at times from either heavy rainfall or patchy fog coverage. Winds out of the northeast will gradually shift northwesterly tonight into Saturday morning behind the departing front and increasing.

DMX WATCHES/WARNINGS/ADVISORIES

None.