textproduct: Des Moines

KEY MESSAGES

- Scattered showers and storms through this morning with isolated hail possible, generally under 1".

- Slight Risk (level 2 of 5) for severe weather for the main line of storms that move through this evening. Damaging winds will be the primary threat, hail secondary. A tornado or two will be possible.

- Dry Friday with storm chances building from the south through the weekend. Likely showers and storms Sunday night and Monday.

SHORT TERM /THROUGH TONIGHT/

Issued at 307 AM CDT Thu Apr 23 2026

Moisture advection resulted in building stratus overnight. The cold front was analyzed in central Nebraska and was the culprit for some early nighttime convection. Ahead of it is the main instability axis fueled by the LLJ. Will need to monitor this leading gradient for sustained updrafts this morning. A secondary LLJ max will build in from the south and provide an elevated frontal boundary in western Iowa and soundings indicate that there is around 1500 J/kg to work with from the top of the moist layer. There may be thunderstorms through the morning, some of which will contain hail. Some of the 00z CAMs presented this activity as an initial line that traces the extent of the CAPE gradient. Capping will re-establish itself behind this first push and some scattered showers will form from the trapped moisture. A dry slot will impede the warm sector and will give a brief pause to precipitation in southwest Iowa before the main line ignites. The early storm coverage will consist of supercells, signaling an early peak for the hail threat, but storms will grow upscale into a QLCS as the front enters the DMX CWA.

For the main line of storms, they'll enter the west close to 00z. At that time, a secondary vorticity max pivots into the region and re- enhances the low and mid-level wind field. 0-3km shear exceeds 30kts ahead of the line and the threat for winds is highest while daylight exists. Curvature of the lowest kilometer of the hodograph hints at continued tornado potential at least early into the night (pending decoupling), but mesovortex generation along the line will be relatively sparse due to the shear vector orientation running parallel to the boundary. Scattered convection will form with the intensifying LLJ ahead of the line, these storms potentially acting as local nudgers when they're ingested by the main line. The window for severe weather will be longest in duration in southern Iowa where the air will be the least contaminated today.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 307 AM CDT Thu Apr 23 2026

A lull of high pressure parks overhead Friday, keeping temperatures in the 60s and conditions dry. Its departure opens the southwestern part of the state to WAA and moisture advection. Saturday has trended wetter there, for this reason. An upper-level jet max will dig into the western CONUS trough and shove a component of it into the Central Plains. Consensus between the deterministic EC and GFS, and even presented in the 12z ensemble data from yesterday morning, is a negatively tilted trough feature that will be pivoting northwest of Iowa on Monday, a favorable placement and orientation for severe weather, synoptically- speaking. With a few rounds of severe weather expected south of here between now and then, it's still a question whether or not the warm sector will manage to get this far north. What can be said is precipitation is likely, including some thunderstorms, Sunday night and Monday. The intensity of storms will be better understood with time.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 640 AM CDT Thu Apr 23 2026

MVFR stratus will lower to IFR through this morning. The leading edge of the lower stratus will feature a line of showers and some thunderstorms. Scattered showers persist behind this initial round, evolving into thunderstorms after 20z east. Have refined timing for the main line of severe storms this evening, the prob 30 groups reflecting a drop in cigs and vsbys from thunderstorms. Gusty southerly winds for much of the day with gusts over 30kts likely. Winds will become northwesterly behind the passage of the last line of storms this evening.

DMX WATCHES/WARNINGS/ADVISORIES

None.