textproduct: Des Moines

KEY MESSAGES

- A few isolated storms skim northern Iowa overnight tonight.

- Additional thunderstorms in southwest Iowa Friday evening and overnight.

- Mostly dry and sunny through the weekend!

SHORT TERM /THROUGH SATURDAY/

Issued at 222 PM CDT Thu Aug 20 2026

High pressure has allowed for tranquil conditions across the area today with a few diurnally driven clouds in southern Iowa. Farther north a shortwave is moving across the upper midwest, resulting in a few thunderstorms across Minnesota. A few high clouds have moved across northern Iowa associated with this wave. The cold front trails across South Dakota and into Nebraska this afternoon and will move east, pushing across Iowa overnight and on Friday. Better forcing will be across Minnesota near the surface low and scattered thunderstorms are expected there, extending along the front. A few of these may skim northern Iowa overnight. While an isolated stronger storm is possible, these will largely be confined north and west of the area where forcing and instability are better phased.

Much of Friday will then be dry with northwest flow helping to bring high level smoke from fires across the Pacific northwest. Another embedded wave riding along the western US ridge will slide across Nebraska and southwest Iowa Friday evening. This will bring another chance for scattered thunderstorms. Forcing is again modest and focused largely west of the area, but with 1500+ J/kg MLCAPE and 40 kts of shear, a few stronger to severe thunderstorms are possible in the evening.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/

Issued at 222 PM CDT Thu Aug 20 2026

Any lingering storms in far southern Iowa should clear out early Saturday morning with dry conditions through the weekend. Another embedded shortwave will move across Iowa late Sunday evening into Monday, slowing from model solutions 24 hours ago. The upcoming work week looks to remain active with embedded shortwaves continuing to ride along the western US ridge with northwest flow across Iowa. A more robust system looks to move across the area on Tuesday and will be the next opportunity for more organized convection. At this time range differences remain with the GFS favoring a southerly track over the Euro northerly track.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1052 PM CDT Thu Aug 20 2026

VFR conditions ongoing and expected to continue through the TAF period. Few showers and isolated storms are starting to skim far north and northeast sections mainly north of KMCW and KALO. There's still a low chance for a shower to impact either site with slightly higher chances at KMCW than KALO. Added shower mention into KMCW prior to start of 06Z TAFs with upstream activity expected to weaken so no mentions at either site after 06Z. High level smoke may keep skies hazy on Friday. Some additional showers/storms are possible into Friday morning but chances are generally less than 30% so did not include any mentions with low confidence. Similarly, may also see some storms in southwest or southern Iowa in the afternoon to early evening, but south and west of TAF sites. Winds out of the south tonight become out of the west to northwest during the day Friday.

DMX WATCHES/WARNINGS/ADVISORIES

None.