textproduct: Des Moines

KEY MESSAGES

- Scattered thunderstorms in far southern and southeastern Iowa through this evening. A few strong to severe storms may be possible in the far southeast, with large hail the primary threat.

- Dry and breezy conditions again Friday and Saturday, promoting critical fire weather concerns both days. A Red Flag Warning has been issued for Friday, and a Fire Weather Watch has been issued for Saturday. - Cooler weather the next couple days, with temperatures bottoming out in the lower 20s or possibly upper teens early Saturday morning.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 329 PM CDT Thu Mar 26 2026

As anticipated, a surface cold front has moved southward across our service area today, and is not approaching the Iowa/Missouri border. In the last hour or two isolated thunderstorms have developed just north of the boundary, but remain elevated and benign for now. Mesoanalysis and soundings illustrate a stout Elevated Mixed Layer (EML) behind the front, with diminishing elevated instability in our area as the boundary continues southward. Deep-layer shear will remain impressive (50-60 KT) in our far southeastern counties through this evening, however, profiles are essentially unidirectional in the effective layer so with only speed shear indicated and meager elevated instability, the threat of severe weather is low and limited to perhaps isolated hail, with a notably higher threat well to our east and southeast in parts of Illinois and Indiana. Nevertheless, isolated to scattered thunderstorms will linger in our southern and southeastern areas into early tonight before dissipating/moving out.

As dry air works into Iowa from the north tonight behind the front, skies will gradually clear while winds remain fairly brisk from the north. On Friday a surface high pressure area will approach from the northwest, with north to northwest breezes sustaining for much of the day before dropping off near sunset as the high moves in. With a dry airmass and fuels and gusty breezes, critical fire weather conditions are anticipated in parts of our area where a Red Flag Warning has been issued. This is discussed in more details in the Fire Weather section below. It will also be cooler on Friday behind the front, with forecast highs only in the lower 40s northeast to lower 50s south. On Friday night, the surface high will be directly over Iowa promoting clear skies, nearly calm winds, and low dewpoints in the teens. This is a good setup for radiational cooling and have trended the temperature forecast downward accordingly, with Friday night/Saturday morning lows now in the lower 20s, and the potential for temperatures to fall into the upper teens in some areas.

On Saturday the surface high will move quickly away to our southeast, even as a broad trough of low pressure develops along the High Plains from western North Dakota down to eastern Nebraska. The tightening pressure gradient between these systems will promote even stronger winds in Iowa, especially our western and northwestern counties farther from the departing high. Forecast soundings show the potential for winds of near 30 MPH with gusts to 40+ MPH in these areas, and with continuing very dry conditions another critical fire weather day is in store and a Fire Weather Watch has been issued. This is discussed in more detail in the Fire Weather section below. The pressure gradient will remain over Iowa on Saturday night so while mixing will greatly diminish, organized moderate south southwest breezes will continue through the night promoting notably warmer overnight temperatures. In fact, Saturday night/Sunday morning lows may be around 20 or more degrees warmer than the previous night in some areas.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 329 PM CDT Thu Mar 26 2026

In the latter half of the weekend the 500 MB flow over the central U.S. will turn to more zonal, then increasingly southwesterly as a series of troughs develop over the western two thirds of the nation. This will eventually open up the Gulf and promote warmer and more active weather across Iowa next week. By Monday a broad surface low pressure trough will cover the western High Plains along the lee of the Rockies, and extend an effective warm front somewhere over or just north of Iowa. This will promote temperatures rising into the lower 80s in at least southern portions of the state, and perhaps farther north depending on the location of the boundary, along with dewpoints surging into the 50s in many areas. On Monday night a 500 MB shortwave will move overhead, providing lift for convective initiation with thunderstorms likely near the frontal zone. For now it remains to be seen how much of Iowa may be affected by any such storms, as the GFS locates the front right across Iowa, while the new ECMWF pushes it farther north and keeps most storms over Minnesota. Thereafter, solutions rapidly diverge with regards to the timing and location of various boundaries and thunderstorm chances, because of a lack of resolution of the details of larger trough evolution to our west. However, it appears likely we will stay generally active with periodic rain and storm chances through the week.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1055 PM CDT Thu Mar 26 2026

Pockets of MVFR are lingering in the north at the beginning of this issuance, so added in TEMPO groups for MVFR for northern sites. Not as confident at KALO at this time, but will monitor trends. VFR will prevail after 3 hours. Gustiness will pause briefly after 10z, returning after 16z. Gusts over 25kts possible in the northeast in the afternoon hours. Winds will become light after 00z, eventually becoming variable overnight.

FIRE WEATHER

Issued at 329 PM CDT Thu Mar 26 2026

On Friday, northwest to north winds of near 15 MPH are forecast with gusts to around 25 MPH. Meanwhile, relative humidity will fall into the 20-25% range across southwestern into central Iowa. Although winds are right at or just below criteria, surface fuels remain cured and dry and relative humidity could even fall below 20% at times. As a result, critical fire weather conditions are likely from southwestern into central Iowa (where relative humidity will be lowest), and a Red Flag Warning has been issued for those areas on Friday.

On Saturday, winds will become south to southwest and even stronger, at speeds of 20-25 MPH with gusts to near 40 MPH at times. In addition, relative humidity will be even lower in the 15-20% range, and possibly even around or just below 15% at times. A Fire Weather Watch has been issued for western and central Iowa for Saturday for continuing critical fire weather concerns, and a later upgrade to Red Flag Warning for part or all of the watch area is likely.

Outdoor burning is strongly discouraged both Friday and Saturday.

DMX WATCHES/WARNINGS/ADVISORIES

Fire Weather Watch from Saturday morning through Saturday evening for IAZ004>007-015>017-023>026-033>037-044>048-057>060- 070>073-081>084-092>095. Red Flag Warning from noon to 9 PM CDT Friday for IAZ044>046- 057>060-070>073-081>084-092>095.