textproduct: Des Moines

KEY MESSAGES

- Gradually drying conditions expected by mid to late morning today, which will gradually reduce recent flooding that has occurred generally between Highway 20 and Interstate 80.

- Scattered showers and non-severe thunderstorms possible late this afternoon to evening, mainly over northern and western Iowa.

- Dry conditions generally expected Sunday through Tuesday, with highs in the mid to upper 80s, followed by a return to more active weather midweek.

SHORT TERM /THROUGH TONIGHT/

Issued at 455 AM CDT Sat Jul 4 2026

Another active period occurred after midnight through the time of this writing, given the development of a cluster of thunderstorms that produced significant rainfall amounts and the issuance of several Flash Flood Warnings generally between Highway 20 and Interstate 80, where rainfall amounts of 2-4 inches have fallen, while higher amounts in the 4-6 inch range were reported specifically over portions of Story and Marshall counties. Storms grew upscale in strength into a developing MCS, which tracked southeast with time into south central and southeastern Iowa, producing occasional reports of 55-65 mph wind gusts as the line gradually turned into a bowing segment. At this point, lingering flooding threats remain the primary concern over the affected areas mentioned above, with current radar showing much lighter rainfall in the form of stratiform rain that is expected to gradually push east/southeast out of the area over the next few hours, only adding little more rainfall to these locations. A few thunderstorms currently over parts of western Iowa should also decrease in coverage with time, as limited shear and weaker forcing keep any concerns for stronger storms at a minimum.

Drying conditions are expected by mid to late morning, with partly to mostly cloudy skies and highs reaching into the low to mid 80s. By late afternoon to evening, a strengthening upper level shortwave is expected to pass from the Dakotas into Minnesota and Iowa, while surface dewpoints reach into the low 70s and instability values increase with values around 2000-3000 J/kg overhead. CAM guidance has been suggesting the development of showers and thunderstorms during this timeframe, mainly occurring over northern and western Iowa. Despite the favorable instability, shear values look to be on the weaker side, leading to more of a pulse storm environment. Outside of lightning, the main hazards would be damaging winds as storms fall apart, along with the potential for additional heavy rainfall. Given the recent flooding over the last 24-48 hours, additional or new flooding are not completely out of the question, given higher PWATS over 1.5 inches and warm cloud depths around 13 kft. Those with outdoor plans for the 4th of July holiday should keep an eye on the sky and monitor the forecast, given this potential for storms later in the day that could impact evening firework events and any other outdoor events.

LONG TERM /SUNDAY THROUGH FRIDAY/

Issued at 233 PM CDT Fri Jul 3 2026

Aside from a few scattered showers at times, we generally get a break from the persistent thunderstorm chances Sunday into Monday, as northerly flow and increasing pressure at the surface fully takes over influence of Iowa. Temperatures respond accordingly, with relatively cooler highs in the mid 80s. Widespread precipitation chances look to return through the middle of next week, but more on that once we are through the weekend.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 636 AM CDT Sat Jul 4 2026

Outside of light rain showers at KALO, dry conditions have returned across much of the area, with any remaining rain exiting over the next hour or so. Localized fog has formed over KMCW and should also diminish within the same time period. Otherwise, VFR conditions should become more common across the forecast area, with mid to upper level clouds overhead. There is a low potential (generally below 30%) for showers and storms over the northern terminals by this evening, but have only included PROB30 mentions at KFOD where the overall potential is considered around 30% at this time. Given the lower confidence on occurrence and placement of any storms that can develop, will need to monitor trends and update accordingly. Otherwise, winds will remain relatively light through the period, with a signal for at least some patchy fog at KMCW and KALO and perhaps further west and south given recent moisture from the fresh rainfall. This fog signal will also be assessed through the day and added/removed as needed.

DMX WATCHES/WARNINGS/ADVISORIES

Flood Watch until 7 AM CDT this morning for IAZ023>028-033>039- 044>050-057>062-070>075-081>086.