textproduct: Des Moines

KEY MESSAGES

- Rain showers, drizzle at times over southern Iowa tonight into Wednesday expanding into eastern Iowa Wednesday night. A few rumbles of thunder possible southeastern Iowa Wednesday night.

- Areas of fog may develop tonight, especially east of I-35 and north of I-80.

- A few severe storms with large hail possible late Thursday night into Friday morning with additional strong to severe storms possible later on Friday.

- Remaining mild if not warm into next week.

SHORT TERM /THROUGH THURSDAY/

Issued at 242 PM CST Tue Mar 3 2026

Early afternoon GOES-East imagery shows low level clouds covering the state with some breaks working their way into parts of northern Iowa. These clouds are a result of a moisture rich boundary layer as moisture streams northward of a baroclinic boundary well south of Iowa. Soundings show this saturation is around 1 to 2km deep just above a drier near surface layer. Patchy drizzle has turned to maybe isolated mist or light fog at midday in parts of central Iowa, which may continue through the daylight hours. The boundary layer will remain saturated with ceilings lowering after dark with forecast soundings indicating a period of fog potential as this moisture becomes trapped beneath an inversion. The most likely location for the fog will to be over northeastern into parts of north central Iowa, perhaps as far east as I-35 and as far south as I-80.

As surface low pressure lifts northeastward towards the Great Lakes Wednesday into Wednesday night ahead of a shortwave trough, this will bring lift into southern and southeastern Iowa and result in rain showers and perhaps even a few rumbles of thunder. Farther north, there will be low level turbulence and with low condensation pressure deficits as far north as Highway 20, drizzle production may occur. However, the lift is largely neutral (+/-1 microbar/s), which would point to this potential being quite limited.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/

Issued at 242 PM CST Tue Mar 3 2026

As this first shortwave trough pulls away Thursday, southwesterly flow will prevail ahead of a more amplified trough approaching from the western US. Southwesterly flow will increase into Thursday night with a 40 to 50 knot 850mb low level jet drawing moist air with dewpoints rising into the 50s over much of Iowa and perhaps low 60s in southern Iowa by later Friday. An initial round of storms is possible late Thursday evening into Friday morning as MUCAPE grows with a few to several hundred J/kg of CAPE in the hail growth region. While the storms will be elevated, sufficient shear exists that a few severe storms with large hail will be possible. As this first round exits central Iowa, low pressure will track towards the state with plenty of strong low level kinematics, a developing right entrance jet streak region, and ample early season instability to work with for strong to severe storms in the afternoon or evening. While there are details to work out with this forecast still 72 hours out, the primary concerns will be large hail and damaging wind gusts as forecast soundings show an elevated warm layer that may limit surface based convection.

As the low pressure departs into Saturday, breezy winds from the northwest will bring in cooler air, though highs will still be 10 to 15 degrees above normal. Dry weather is also expected through the weekend into early next week as temperatures rebound back into the 60s as breezy winds from the southwest develop. The next chance for rainfall and thunder may arrive as early as next Tuesday.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1101 PM CST Tue Mar 3 2026

Dense fog has settled in over KMCW and KFOD and will expand to KALO in the next 6 hours. Less fog for southern sites, but they will experience prevailing MVFR, followed by IFR in the morning. Improvements to MVFR possible for a time after 18z, but cigs will drop again after 00z.

DMX WATCHES/WARNINGS/ADVISORIES

None.