textproduct: Des Moines

KEY MESSAGES

- Scattered showers and isolated thunder possible over northeastern Iowa late this afternoon and evening. Severe weather is unlikely.

- Increasing potential for accumulating snow late Monday into Tuesday morning, primarily over southwestern Iowa. Light snow and rain then drifts north through Tuesday, but accumulations are minimal farther north.

- Additional shower and thunderstorm chances over the area Wednesday. Severe threat appears low at this time.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 246 PM CDT Sun Apr 5 2026

By April's standards, today has been a quite pleasant day so far with sunny skies, temperatures in he 50s and some breezy winds. These dry and mild conditions will persist through the afternoon and evening for most of the area, before another cold front drops into the state this afternoon and evening. Along the leading edge of this front, a stunted layer of instability looks to develop, with roughly 200 to 400 J/kg of MUCAPE. Steeper lapse rates, forced ascent along the front, and saturated mid-levels all point toward some scattered shower and isolated thunderstorm potential moving through northern Iowa late this afternoon and into the early evening. Weak instability will limit any severe risk, but dry air below the showers and breezy winds aloft may result in some breezier winds beneath any showers or storms this evening. Even without showers, breezy winds may persist along the boundary as it continues southward through the evening and cold air advection fills in behind.

Another push of surface high pressure fills in over the state tonight into Monday, bringing cooler temperatures and highs in the 40s on Monday. As the high pressure and cooler air mass moves in, it will meet a stream of warmer, moist air advecting northward from the Oklahoma and Texas panhandle regions. Weak frontogenesis along the periphery of these two air masses will lead to weak lift over southwestern Iowa on Monday morning, with light rain or a few snowflakes possible. However, dry low to mid-level air will inhibit most of this precipitation, working against rain/snow chances during the day on Monday and keeping precipitation light.

The confluence between these two air masses will be increasing through the day Monday, as warm, moist air continues northward and overruns the colder, drier air mass in Iowa. As a result, frontogenesis from roughly 850 to 650 mb will continue to increase through Monday evening and maximizes overnight Monday into Tuesday morning. -20 to -30 microbars of lift and increasing moisture through the layer will allow for top-down saturation and dynamical cooling of the layer below and result in a narrow band of accumulating snowfall overnight. Recent guidance has really begun to trend upward on QPF amounts within this targeted band, translating to 4" plus snowfall amounts being produced by Cobb snow ratio output. While these higher end amounts aren't consistent across guidance at this time, the potential for accumulating snow overnight Monday into Tuesday morning has increased. Forecast snowfall amounts have been adjusted up accordingly to around 1 to 3" over southwest Iowa, with some locally higher amounts possible within the heavier band. Snow then looks to transition to a light rain as warmer air advects in during the day on Tuesday, although the rain period appears brief before saturation is lost. Light snow and rain will drift northward through the day on Tuesday, but won't have near the lift that will be present in southwest Iowa on Tuesday morning, keeping precipitation lighter farther north in the state Tuesday afternoon and evening.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Issued at 246 PM CDT Sun Apr 5 2026

The wave lifting northward on Tuesday will meet a more amplified northern stream trough on Wednesday. Warm and moist southerly flow ahead of these two waves will bring gulf moisture up into the state, bringing more potential for showers and thunderstorms on Wednesday. Instability looks rather weak with this system, keeping the threat for severe thunderstorms low. The southern portions of the state remain open to the gulf in some capacity through Thursday and Friday, although a brief lull in precipitation will likely occur for areas farther north and west as the upper level wave departs west Thursday into Friday. The entire state opens back up to the gulf as troughing builds over the western CONUS into the weekend, leading to a more moist and active pattern next weekend.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1228 PM CDT Sun Apr 5 2026

VFR conditions prevail under clear skies over Iowa. Winds have become breezy out of the northwest this afternoon, sustained at 10 to 20 kts with gusts around 25 to 30 kts possible. Scattered showers with some isolated thunder are possible across northern Iowa early this evening, impacting KMCW and KALO. Due to low confidence in thunder at terminals, have kept PROB30 of showers for now and will amend for any threats of thunder. Winds then shift to the north tonight as a boundary passes through the state.

HYDROLOGY

Issued at 246 PM CDT Sun Apr 5 2026

Water continues to route through area rivers, with many rivers approaching crest or already on their way down. The Cedar River near Cedar Falls remains the primary site of concern, where the current level has all but reached minor flood stage. The Iowa River near Tama is still expected to near, but stay just below minor flood stage early next week. Mostly dry conditions in these areas over the next few days should give rivers some time to route water through the system and build some degree of capacity in the soils, but likely won't fully recover to previous levels prior to additional rainfall later this week. Therefore, we continue to watch trends in rainfall amounts and placement as we go through the week and especially into the upcoming weekend.

DMX WATCHES/WARNINGS/ADVISORIES

None.