Decatur, IA 50067 Weather

Key messages

- Calm and dry through Thursday night as high pressure sets in over the region.

- Rain chances return on Friday and continue into Saturday (50-60%) with the best chances along and south of Highway 30.

- Temperatures look to remain above normal for the next week with additional chances for showers and thunderstorms.

Short term

Issued at 158 AM CDT Thu Oct 29 2026

The cold front promised in yesterday's forecast is currently making its way across Iowa as noted with a windshift across much of the state - winds out ahead of the front are from the southwest while winds behind it are from the northeast. As expected, temperatures are also a fair bit lower to the north where the front has already passed. Even with temperatures in the 40s, much of northern and western Iowa still looks to see above normal lows. As an aside, while both the daily highs and lows are forecast to be above normal, the European Extreme Forecast Index (EFI) shows that the magnitude at which overnight lows will be above normal is higher than that of the daily highs through much of the short and long term forecast periods.

On the topic of temperatures, highs for the next few days were poked down a degree or two. For today, the biggest uncertainty lies in the forecast highs across southern Iowa. While skies behind the cold front should generally be clear, cloud cover across southern Iowa may linger for long enough that the highs near 70 won't be realized. Otherwise, today looks to be dry with light winds as high pressure sets up camp just to our north in Minnesota/Wisconsin. The high pressure will help bring flow from the north and east, leading to cooler temperatures. The lows for tonight look to be normal-ish, though still a bit warmer than normal for this time of year.

Friday brings the next potential for showers and thunderstorms as a low will attempt to lift into the area from the southwest. Flow at 850mb looks to be out of the south providing moisture, although uncertainty lies with how far north the low makes it, especially given the potential influence of the high sitting to our northeast. In other words, the northern extent of PoPs depends on how quickly the high can be ushered out of the region. The severe potential for tomorrow looks abysmal at best, with <500 J/kg of MUCAPE, though a few rumbles of thunder can't be ruled out, especially across southern Iowa.

Long term

Issued at 238 PM CDT Wed Oct 28 2026

A complex, amplified upper air pattern will dictate the extended forecast. Rain chances will loom for much of the period, including through the weekend to start. Timing differences still remain for Saturday on when precipitation will pause, but for now, it appears a warm front will lift northward towards Minnesota through the day, but there is enough uncertainty in remaining moisture to warrant keep a ~30% chance of rain in the area for Halloween night. Lee cyclogenesis will temporarily pull away moisture from the area Sunday, but it will return with a large closed system to start next week. Location of the warm sector is still uncertain as the formation of the closed low involves the combination of a couple component waves merging together. What can be said is the resultant feature will become wound up in the central US and will result in an extended period of rain chances, cloud cover, and cooler temperatures for the first week of November. It's possible that highs next week don't reach 70 degrees for the area.

Aviation

Issued at 1112 PM CDT Wed Oct 28 2026

Scattered showers and a few thunderstorms will remain over parts of central Iowa through 09z with the greatest chance at KOTM. A fragmented area of MVFR stratus is following a boundary which is moving through the area. Guidance suggests this will reorganize over southern Iowa later tonight and into early Thursday morning. Have included MVFR cigs at a few sites. VFR conditions will then prevail for much of the day Thursday. The wind will turn northwest then northerly overnight with the fropa. A shift to northeast wind is expected late.

Watches, warnings and advisories

None.