textproduct: Des Moines

KEY MESSAGES

- Intermittent shower and occasional thunder chances today through Thursday. No severe weather expected.

- Cool, dry temperatures Thursday through Saturday may result in some frost and/or freeze impacts in the mornings.

SHORT TERM /THROUGH THURSDAY/

Issued at 207 PM CDT Tue Apr 28 2026

Rather mild conditions prevail over the state today as the influence of yesterday's surface low departs and surface high pressure works it's way into Iowa. The cooler, drier air mass advecting in from the north has been apparent on surface observations, with temperatures generally in the 50s and dewpoints dropping into the 30s, which is over 20 degrees drier than this time yesterday. This dry near surface air will play a notable role in our precipitation chances this afternoon and evening, as a subtle wave works in from the west and interacts with moisture aloft. Precipitation will initially evaporate before reaching the surface, as is being shown by the hydrometeors visible over western Iowa on the 0.5 degree scan from KDMX which are nowhere to be found on the 0.5 degree scan at KOAX that is sampling lower to the ground. However, as we got through the afternoon, better forcing should help to saturate down through the dry layer, allowing for at least occasional sprinkles or light rain to occur, especially over southwest into south central Iowa. Have increased precipitation chances to around 25 to 35% for these areas. Additional light rain/sprinkles are possible farther north and east through the evening, but with little to no QPF expected, have kept PoPs lower with sprinkles mentioned overnight.

The light, scattered shower chances will see a brief lull through Wednesday morning before more chances move into the area Wednesday afternoon. The forcing and moisture available Wednesday afternoon will be lower, but will have a shallow layer of instability present. With this thermodynamic support, can't completely rule out at least some light showers and potentially a rumble of thunder over northern Iowa Wednesday afternoon, given the 100 to 200 J/kg of MUCAPE. That said, the lack of any prominent moisture stream, dry low levels, and minimal forcing mechanisms, have kept PoPs low around 20%. Aside from precipitation potential, the more widely observed outcome tomorrow will be cumulus filled skies within the shallow unstable layer.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/

Issued at 207 PM CDT Tue Apr 28 2026

Light rain chances continue once again on Thursday, as a weak boundary attempts to develop precipitation over southern Iowa in the afternoon and evening. With the northwesterly flow pattern continuing aloft and the gulf moisture shunted south, low level moisture will once again be a limiting factor, although the upper level moisture may still be sufficient for at least light showers. A shallow layer of instability will develop again, introducing at least a low chance a few rumbles of thunder. Severe weather chances will be minimal.

The broad Canadian upper low remains parked to our northwest through the end of the week, keeping cool and dry conditions overhead. These cool temperatures and dewpoints, in combination with surface high pressure moving in, will introduce some frost and/or freeze potential in the mornings Thursday through Saturday, mainly over northern Iowa. Thursday morning's temperatures will be the warmest, with lows in the mid 30s over far northwestern Iowa, and dewpoints generally in the low 30s. However, Friday and Saturday mornings look like good candidates for radiational cooling and temperatures falling near or below freezing. Should clear skies and light winds develop under the high pressure, frost and/or freeze impacts could occur. However, even a small amount of cloud cover or slightly higher winds could limit cooling and keep forecast lows just above freezing and frost production lower. Therefore, will continue to monitor the frost/freeze potential this week. The Canadian upper low will begin to move off to the east through the second half of the weekend, allowing slightly warmer temperatures to work their way in Iowa through the beginning of next week.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1054 PM CDT Tue Apr 28 2026

Light showers or drizzle remain across portions of western Iowa moving into central Iowa where drier air remains but could still have some light drizzle/sprinkles reach into portions of central or even east central Iowa with time. No precipitation mentions included in the TAFs with impacts minimal if anything should occur, but confidence low of any impacts within 5SM of a TAF site. VFR conditions otherwise generally ongoing with some brief dips into MVFR in the far west, but VFR largely expected to continue with clouds clearing into Wednesday morning, but then cumulus developing through the afternoon. Light and variable winds tonight settle out of the northwest during the daytime Wednesday, increasingly slightly, but generally less than 12 knots, a few higher gusts. Some additional rain chances later Wednesday, but largely towards the end of the TAF period with low confidence in impacts at TAF sites.

DMX WATCHES/WARNINGS/ADVISORIES

None.