textproduct: Des Moines

KEY MESSAGES

- Flurries to a dusting of snow possible across northern Iowa this morning.

- Winter system moves through late tonight through Sunday, with strong winds on Sunday leading to potential blizzard conditions. Highest snowfall accumulations expected over northern and eastern Iowa. A brief period of freezing rain possible as rain transitions to snow Sunday morning.

- A few thunderstorms possible central and south on Sunday morning. Hail would be the main concern with any storms.

- Wind gusts of 50 to 60 mph Sunday afternoon into early Monday. A High Wind Watch has been issued across Central Iowa.

UPDATE

Issued at 414 AM CDT Sat Mar 14 2026

A look at radar this morning shows areas of patchy reflectivities over central Iowa, as the wave in relation to the mid-level trough in the western CONUS tracks eastward. Though mid-level moisture is sufficient, given the presence of widespread cloud cover and the radar returns, surface observations have all remained dry, which is due to the very dry near surface layer of air across Central Iowa. A bit further north and west into South Dakota, a few sites are indicating snow with lowered visibilities, but with drier air further east, would not expect snow to occur as it reaches into Iowa. This dry setup really doesn't change through the morning, therefore not expecting any notable snow to reach the surface. However, some flurries and at most a dusting could occur, with the best potential over northern Iowa if anything does make it to the ground, as a few deterministic models suggest.

The most changes in terms of recent forecast trends all exist within the time period that the widely known winter storm is expected to pass through the Midwest. Latest model runs continue to shift the initial QPF axis of precipitation a bit further north, which keeps much of the snow accumulations out of Iowa Sunday morning. However, still seeing a band of ice glazing caused by mixed precipitation covering northern into parts of north central Iowa during much of the morning, as model soundings show an elevated warm layer while the surface hovers right around freezing. Therefore have not changed coverage or timing of the current Winter Storm Watch over northern Iowa. Thunder at times with the frontal passage Sunday morning is still possible as guidance places at least lower values of instability into much of central Iowa, with a Marginal risk for isolated severe storms still in the far southeast portion of Iowa. For snow accumulations, variability still exists on the overall coverage of amounts as the deformation zone arrives into Iowa Sunday afternoon and through the evening. The NAM, GFS and Euro have continued the trend of higher snowfall amounts (over 4 inches) mainly east of I-35, and lesser amounts west, while the RAP and HRRR show accumulations of 4+ inches mainly over northern Iowa with this second wave, and lesser amounts south. Have continued to favor the higher amounts over northern and eastern Iowa given these recent trends.

Regarding winds with this system, confidence continues to grow on widespread high winds across much of Iowa, as 850 winds are indicated around 60-70 knots overhead as the system passes through, with strong north/northwesterly flow (CAA), which is a favorable setup in this regime to pull down the stronger winds aloft. HREF and NBM probabilities indicate 50% or greater potential for wind gusts over 50mph by Sunday afternoon through early Monday morning, which has lead to the coordinated issuance of a High Wind Watch that covers all of Central Iowa, in which will later be converted into a warning if confidence continues to increase in occurrence. These winds will certainly lead to widespread blowing snow across the forecast area, regardless of overall snow amounts in any given area, leading to travel impacts due to lowered visibilities, on top of slick conditions caused by accumulating snow. These overall impacts have also led to a slight expansion south a row of counties for the Winter Storm Watch, with additional edits to the coverage of headlines and conversions of the watches to warnings expected later today or early Sunday. Stay tuned for updates.

SHORT TERM /THROUGH MONDAY/

Issued at 301 PM CDT Fri Mar 13 2026

Our first sign of arrival for this system is this morning, as a wing of theta-e advection lifts northward into the state. Moisture availability aloft will be plentiful with this wing, but lacking at the surface, meaning top-down saturation will need to take place before snow reaches the ground. This has been trending drier with recent guidance, but have maintained at least light snow accumulations (under an inch) along the Iowa/Minnesota border.

The main synoptic wave will approach the area through the day on Saturday, streaming warmer air and a healthy plume of moisture up into the state into the evening and overnight hours. This will result in a broad swath of heavy snowfall mainly over Minnesota and Wisconsin, and potentially far northern Iowa Saturday night into early Sunday. That said, the recent trend in guidance has been farther north with this initial band overnight Saturday into Sunday, with most of guidance keeping snow out of Iowa through 12z on Sunday. To account for this drier trend Saturday night, have pushed the start time for the Winter Storm Watch back to 06z on Sunday, which may still be too early if the band doesn't wiggle back southward.

While the initial band of snow is trending north, these solutions also result in more instability being pulled up into Iowa early Sunday morning. Dry mid-level air may inhibit storm development, but a few rumbles of thunder can't be ruled out as the low passes overhead Sunday morning, especially along the warm front. Hail would be the main concern with any storms, and severity looks low given instability values generally under 500 J/kg. That said, the Colorado State University machine learning severe probabilities are keying on some hail probabilities over Iowa and the storm prediction center does have an outlook for general thunder and a marginal risk for severe weather in far southeastern Iowa early Sunday, so will want to at least keep the potential for storms in mind.

Given the guidance today, what looks like the main story of this system will be the TROWAL development and wrap around precipitation occurring behind the surface low passage during the day on Sunday, in addition to very strong winds developing behind the low. The GFS and NAM are most bullish on this wrap around snowfall, showing anywhere from 3 to 6 inches on average, with even higher amounts along northern Iowa pushing 10"+ by Monday morning. These two solutions also show the surface low deepening overhead, while other solutions have it deepen farther east instead, which results in heavier snowfall amounts over eastern Iowa and lower amounts in central Iowa, generally in the 0 to 2" range. Therefore, confidence is low in the amount of snow that will fall on Sunday but confidence is high for strong winds developing with gusts of 45 to 55 mph possible, similar to this morning. Any snow that does occur on Sunday with these winds will lead to blizzard-like conditions, at least while the snow is falling. Therefore, while there is a lower likelihood of the initial heavy snow band impacting northern Iowa Saturday night into Sunday, and uncertainty still exists with total snow amounts during the day on Sunday, the winter storm watch will remain in place for much of central into northern Iowa for the potential blizzard conditions on Sunday. Even if we don't get snow, winds will be approaching high wind criteria over much of the state as well, so wind headlines will eventually be needed. Strong winds will continue into Monday morning. Depending on the amount of snow that falls on Sunday, blowing snow could persist into early Monday morning, impacting the Monday morning commute as well.

Finally, as if there wasn't enough to consider already with this system, we are also monitoring potential for some freezing rain and/or ice pellets as the cold air initially arrives on Sunday morning. This likely wouldn't be long lived, as liquid precipitation transitions over to a snowfall with the colder temperatures, but a few hours of freezing rain may still lead to a light glazing of ice before snow falls on top of it. This threat looks most likely over northern Iowa early Sunday morning, but could develop in portions of central Iowa as well.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

Issued at 301 PM CDT Fri Mar 13 2026

Winds will remain breezy but steadily diminish through Monday afternoon and evening. Temperatures will be much cooler on Monday with highs only reaching the teens to low 20s. These cooler temperatures then continue into into Tuesday with one more weaker system bringing snow potential Tuesday night into Wednesday. Beyond Wednesday, ridging then builds in from the west, warming temperatures through the end of next week. This should help to melt any snow on the ground, with the return of highs in the 50s and 60s possible by next weekend.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 649 AM CDT Sat Mar 14 2026

VFR conditions remain across the terminals this morning, with cloud cover decreasing over the southern portion of Iowa briefly through the morning, before more widespread clouds return this afternoon to evening. MVFR to even IFR ceilings are expected to return from north to south after 06z Sunday, along with rain showers over most terminals outside of KOTM. Could get some storm activity during the morning, though overall confidence is low so have left out of the current issuance, and will assess further over the next several updates. Southeast winds increase this morning to afternoon, with gusts up to 20-30 knots, then shifting southerly at KOTM and KDSM after 06z and eventually northwesterly across the state after 12z following a frontal passage. LLWS is expected mainly at KDSM and KOTM during the morning given the shifting winds through the low levels.

DMX WATCHES/WARNINGS/ADVISORIES

Winter Storm Watch from late tonight through Monday morning for IAZ004>007-015>017. High Wind Watch from Sunday afternoon through late Sunday night for IAZ004>007-015>017-023>028-033>039-044>050-057>062- 070>075-081>086-092>097. Winter Storm Watch from Sunday morning through Monday morning for IAZ023>028-033>039-044>050-057>062-070>075.