textproduct: Des Moines

KEY MESSAGES

- Band of moderate to heavy snowfall passing through central and north central Iowa this afternoon and evening. Snowfall amounts of 6 inches or more are possible within the heaviest band.

- Few showers and rumbles of thunder in southern and southeastern Iowa this afternoon and evening. Rain may transition to a freezing drizzle or snow overnight.

- Cold and dry Friday through the weekend.

DISCUSSION

Issued at 219 PM CST Thu Feb 19 2026

Radar returns are increasing over southern Iowa showing our first indications of the approaching low pressure system today, which will eventually bring a band of moderate to heavy snow to the state this afternoon through the evening. Dry sub-cloud air is limiting most of this precipitation from reaching the ground, but rain and/or frozen precipitation has started being reported under some of the better returns. Interestingly enough, even some lightning has been detected in Taylor and Adams counties. Most of this precipitation will be light initially as it works through the dry air, but areas with more convective elements could see more substantial showers.

As we continue through the afternoon, the parent wave and surface low will continue to lift nearer to the state, bringing better forcing in the form of mid-level warm air advection and frontogenesis. This will drastically increase lift through the saturated mid-levels, leading to increased hydrometeor production and better top-down saturation to the surface. Despite the dry low levels, the expectation is for this top-down saturation to happen fairly quickly with 20 to 30 microbars of lift through the mid- levels and dendritic growth zone. As this saturation occurs and colder air moves in, temperatures will begin to wetbulb down to and below 0C, quickly transitioning any rain over to snow.

Moderate to heavy snow is expected beneath the areas of strongest lift, resulting in periods of inch per hour snowfall rates. These rates will quickly cool off any warmer air remaining at the surface and overcome warmer ground temperatures to allow for accumulating snow. Fortunately, the heaviest band seems somewhat progressive as it lifts northward, which should help reduce residence time under the heaviest rates and keep snowfall amounts in the 1 to 3 inch range for most of central Iowa. However, there will likely be an area where residence time under the band is increased due to the system pivoting and band wrapping around the low as it translates eastward. This increased residence time will lead to a southwest to northeast oriented swath of locally higher amounts of 3 to 6+ inches of snowfall. The forecast and guidance has narrowed in on a likely location for these higher amounts, running roughly from Omaha through Ames and up into Waterloo. However, any small shift in the storm track could shift these higher amounts slightly farther north or south with a sharp cut off on either side. Given the expectation for a band of heavier snowfall rates and accumulations nearing 6 inches or more, have upgraded the Winter Weather Advisory to a Winter Storm Warning through the expected areas. It is worth noting that, given the nature of the band, there will likely be some areas in the warning that only see a couple of inches snow. However, the potential for higher end snowfall under the band, resulting in impacts to travel both from accumulating snow and from low visibility in the higher rates and breezy conditions, is what warranted the broader warning area.

While mostly snow looks to fall over central into northern Iowa, southern and southeastern Iowa could be looking at a slightly different subset of conditions. These locations will have slightly warmer air and drier mid-levels, which introduces some other hazards both prior to and after the cold air arrives. First, as the warm air advection wing starts to saturate through the layer this afternoon, we may see a period of light rain/showers and potentially more rumbles of thunder given the small amounts of instability (~100 to 200 J/kg of MUCAPE) still lifting over the southern portions of the state. Then, as the colder low level air begins to fill in behind the low, the column will begin to cool below freezing. As this occurs, some soundings also show a loss of saturation through the dendritic growth zone. No ice introduction implies a higher likelihood for supercooled droplets mixed in with the ice crystals, which could lead to some freezing rain or freezing drizzle tonight. Fortunately, this is where the warmest surface temperatures reside, which may initially inhibit freezing. This loss of ice introduction isn't a persistent signal, either, with saturating dipping in and out of the DGZ. Therefore, this is a lower confidence scenario, but will need to be watched closely this evening as roads could become slick after they drop below freezing.

Precipitation generally wraps up early Friday morning, but travel conditions may remain deteriorated into the morning commute as plows work to get roads cleared, especially in the areas with the heaviest snowfall. Temperatures don't warm above freezing on Friday, but clearing skies in the afternoon should at least help with snow removal on Friday. Winds also remain breezy through Friday morning, which could lead to some drifting of fresh snow, but blowing snow shouldn't be a widespread issue. Conditions then remain much cooler and dry through the weekend with light to potentially breezy winds by Sunday.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 607 PM CST Thu Feb 19 2026

A wintry mix has expanded across much of Iowa this evening. Precipitation type varies across the area from snow west of I-35 to a rain/snow/ice pellet mix east of I-35. Parts of southern Iowa have seen more sleet along with thunder. A transition to all snow is expected over the next few hours. MVFR to IFR ceilings are in place across most sites. As the heavier snow band sets up overnight expect both ceilings and visibility to fall to IFR and perhaps reach LIFR in the heaviest portion of the band from around 03-08z. Where this narrow band sets up is uncertain, but mostly likely impacted sites would be KDSM/KALO. This will be fine tuned through the evening. Snow tapers off through the early morning hours on Friday with improvement back to VFR around or after 18z.

DMX WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until 6 AM CST Friday for IAZ017-025- 061-062-073-074. Winter Weather Advisory until 6 AM CST Friday for IAZ023-024- 033-034-071-072-081-082. Winter Storm Warning until 6 AM CST Friday for IAZ026>028- 036>039-048>050-060. Winter Storm Warning until 6 AM CST Friday for IAZ035-044>047- 057>059-070.