textproduct: Des Moines

KEY MESSAGES

- Cold front across Iowa today with breezy north winds gusting 25- 35+ mph behind the front.

- Showers and thunderstorms develop along the front in the late afternoon and evening, possibly clipping southeast Iowa. Non- severe showers and thunderstorms percolating across southern Iowa through the overnight to Wednesday morning.

- Additional showers and thunderstorms on Wednesday, a few severe possible far southern Iowa. Showers continue into Thursday. With colder air filtering in north, a wintry mix is possible across southern Iowa from Wednesday evening through Thursday.

- Another round of thunderstorms on Friday with severe potential.

SHORT TERM /THROUGH TONIGHT/

Issued at 301 AM CDT Tue Mar 31 2026

Early this morning the surface low was situated across eastern Nebraska with the warm front draped across northern Iowa. Temperatures ranged from the low 50s in northern Iowa north of the boundary to mid 70s in southern Iowa on the warm side. Storms along the warm front on Monday evening have largely pushed east of the area early this morning. Meanwhile, mesoscale analysis shows the low level jet pushing into southwest Iowa. While earlier CAMs indicated potential convection with this LLJ, so far this has not materialized. A few weak showers did develop after midnight in northwest Missouri and satellite shows colder cloud tops in that area, but more robust development has not occurred.

Today the cold front will push across Iowa. In many cases the temperatures early this morning will be the high for the day. Southeast Iowa will have some additional time to warm ahead of the front. North winds will gust 25-35 mph behind the front, supported by soundings with 25-35+ kts through the mixed layer as cold air advection and subsidence helps to pull higher winds to the surface. Winds will be strongest in northwest Iowa. Late this afternoon thunderstorms are expected to develop along the cold front. Most data has the cold front clearing the area before this develops, however it is possible that a few stronger storms may clip parts of southeast Iowa. The primary hazard is large hail with any storms that develop on the boundary in southeast Iowa with MLCAPE of 1000+ J/kg. The LLJ develops overnight across Missouri into southern Iowa. This will help to increase moisture and convergence across the area, allowing for scattered showers and thunderstorms across southern Iowa through the overnight and Wednesday morning.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 301 AM CDT Tue Mar 31 2026

A weak low out of the southwest will lift into the area on Wednesday. This will mainly serve to pull in deeper moisture transport into the area out of the Gulf ahead of an approaching upper level trough and allow for scattered shower activity through the day. By the time the trough reaches the area Wednesday afternoon and evening a few thunderstorms will develop on a boundary from southern Iowa through Missouri and south. Strong to severe storms are possible, but most of this activity should remain south of the area. Meanwhile, colder air will filter in from the north with the incoming trough. Soundings have a better warm nose compared to last night's model data, however surface temperatures are still right around 0C. The combination of higher rain rates with marginally cold surface temperatures will limit ice accumulation, despite what the GFS and NAM would like to produce at the IA/MN border. A wintry mix with wet flakes is more likely given the thermal profile at this time, though very light ice could occur on elevated surfaces. Wrap around precipitation will continue across Iowa on the north side of the low through Thursday, and the continued cold air advection will allow for a continued wintry mix in northern Iowa with rain central and south. The low will lift east Thursday with precipitation clearing the area through the afternoon and evening.

A deepening trough across the western US reaches Iowa by Friday, bringing a chance for thunderstorms by afternoon to evening. Severe storms are possible, though the extent will depend on the track of the surface low. Right now models pull the surface low across Iowa with MLCAPE of 1500 J/kg into the area with 30-40 kts of 0-6 km shear. Drier and seasonably cool temperatures in the 40s to 50s arrive for the weekend into early next week.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1115 PM CDT Mon Mar 30 2026

A line of storms is along and just north of an ADU-DSM-GGI line and is expected to drift just north of east over the next few hours. Have delayed the PROB30 TSRA at OTM until late tonight as possible new development moves into the area. Low level winds have also increased so may see periods of LLWS at all sites sporadically, but most consistently at OTM and ALO so have included at those terminals. As a cold front moves through tonight into Tuesday morning, gusty winds from the north will prevail much of the remainder of the period. A short period of MVFR ceilings will pass over at least ALO with trends removing this from MCW in this issuance. Finally, additional storm chances will be possible at OTM along the front and a TSRA PROB30 group was included. Additional storms may lift back into the state toward the end of the period, but will wait on inclusion until confidence in timing increases in future issuances.

DMX WATCHES/WARNINGS/ADVISORIES

None.