textproduct: Des Moines

KEY MESSAGES

- Enhanced Risk (level 3 of 5) in eastern Iowa. All severe hazards, including large hail, damaging wind, and tornadoes, are possible with storms today.

- Much cooler this weekend with overnight lows in the 20s and 30s.

- Mild and dry to start the week with thunderstorms returning to the forecast by late week.

SHORT TERM /THROUGH TONIGHT/

Issued at 101 PM CDT Fri Apr 17 2026

The surface low early this afternoon is centered across north central Iowa with attendant sharp cold front pushing across the state. The impact was already being felt this morning in northwest Iowa when Estherville fell from 71 degrees at 10am to 43 degrees by 10:07am. Early convection has bubbled in northern Iowa and into Minnesota associated with lift in the vicinity of the surface low. The cold air sharply undercuts the warm and deeply unstable air in place with the primary trough farther to the west. This will allow for a period of some post-frontal elevated storm development, something already noted with elevated showers in northwest Iowa this morning behind the surface front. Across the state two primary ares of convective development are anticipated into the afternoon, noted in midday satellite imagery. The first is pre-frontal convection developing in an area of convergence noted in surface observations across eastern Iowa and visible in a plume of cumulus. A second line of cumulus trails along the cold front across western Iowa that will push across Iowa through the rest of the afternoon.

Much of the prefrontal convection is expected to develop east of the area, perhaps clipping far southeastern parts of the area near Ottumwa. There is plenty of available instability with 3000-4000 J/kg of MUCAPE (3000+ MLCAPE) and steep mid level lapse rates of 8+ C/km. Much of this instability is elevated with very little in the lowest 3 km (<100 J/kg). This will limit low level stretching and some of the tornado potential locally, though it is certainly NOT eliminated. The steep mid-level lapse rates, along with well curved hodographs in the low levels will help with rotating updrafts and hail growth. Storms are expected to quickly grow upscale. As this happens the initial discrete development will become multi-cell to linear as it pushes east, transitioning to a damaging with threat with tornado potential along the line.

LONG TERM /SATURDAY THROUGH FRIDAY/

Issued at 101 PM CDT Fri Apr 17 2026

Much colder air pushes in with the cold front as temperatures fall into the 30s tonight. Saturday remains breezy with continued cold air advection and the enhanced pressure gradient across the area. Temperatures in the upper 40s north to mid 50s south with 20-25 mph wind through the day. By Sunday winds relax with temperatures warming slightly into the 50s to low 60s. The thermal ridge builds next week, bringing 70s back to the area. Much of the week is dry with storm chances returning late in the week.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 642 PM CDT Fri Apr 17 2026

Isolated showers and thunderstorms are possible in the next few hours, but low probability of impact at any given point precludes TAF mention. Brief MVFR ceilings may also be possible through 06Z, but would be highly localized and sporadic. Skies will then clear overnight, the VFR conditions continuing. Gusty northwest winds will occur during the TAF period, especially in the next several hours and again during the day on Saturday, but with only a modest dropoff overnight tonight.

DMX WATCHES/WARNINGS/ADVISORIES

None.