textproduct: Des Moines

KEY MESSAGES

- Scattered thunderstorms have developed on a weak boundary across Iowa this afternoon and will move west to east across the area through this afternoon. Isolated gusty winds are possible.

- Hot and humid conditions continue through Saturday with a Heat Advisory in effect for much of southern and central Iowa.

- A few scattered thunderstorms are possible in northern Iowa on Saturday with more widespread showers and thunderstorms possible on Sunday.

SHORT TERM /THROUGH SUNDAY/

Issued at 234 PM CDT Fri Sep 4 2026

A weak boundary is in place across the area, noted as a wind shift in the surface observations and as a narrow line of clouds in GOES satellite imagery. There is a substantial EML in place this afternoon and isolated convection that has managed to develop on this boundary is quite elevated. While severe storms are not anticipated, soundings are fairly dry in the low levels and this could create an environment supportive of gusty winds as rain cools the column. With very little shear in place these storms will be very short lived and pulsey in nature as the boundary pushes east.

On Saturday the thermal ridge nudges farther north and will push the repetitive convection on the edge of the ridge farther north as well. A weak embedded wave will ride along this with an MCS moving across South Dakota overnight. The decaying MCS will allow for scattered shower and thunderstorm activity reaching northwest Iowa Saturday morning, continuing into the early afternoon across the north. Otherwise, the story on Saturday will be the heat with heat indices of 100-105 prevalent across central and southern Iowa for yet another day. Those with outdoor plans will need to take appropriate safety precautions to stay safe in the heat.

Temperatures come down a few degrees on Sunday as another embedded wave rides over the ridge, sinking farther into Iowa with more additional scattered showers and thunderstorms possible through the day. As has been the case the past several days, the severe risk remains low but gusty winds are possible with collapsing updrafts.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Issued at 234 PM CDT Fri Sep 4 2026

Early next week the western US trough will deepen and organize, pushing east. This will create an opportunity for more organized convection early in the week with increased shear and upper level support across the area. The main cool front associated with the system pushes across Iowa Tuesday and Wednesday, bringing temperatures down a few degrees by late week.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1241 PM CDT Fri Sep 4 2026

Light south southwest winds through today. Then a weak boundary will pass from northwest to southeast very slowly through the period resulting in a period of variable winds. Northern sites shift to easterly by this evening while wind shifts at KDSM/KOTM are less pronounced.

DMX WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 7 PM CDT Saturday for IAZ033>039-044>050- 057>062-070>075-081>086-092>097.