textproduct: Des Moines

KEY MESSAGES

- Windy and dry conditions today, potentially leading to erratic fire behavior.

- Light rain/snow possible over far northern Iowa tonight into early Sunday morning. Minimal accumulations expected.

- Freezing temperatures possible north tonight into Sunday morning, then over much of central Iowa Sunday night into Monday.

- Warm and mostly dry through the first part of the work week.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 227 PM CDT Sat Apr 18 2026

Breezy northwesterly winds prevail over the area today, gusting up to 40 mph as efficient mixing occurs under mostly clear skies. A much drier air mass continues to advect into the state from the west, causing dewpoints to fall into teens to low 20s. Resulting relative humidities have begun to dip into the 20 percents over portions of western Iowa, which combined with the gusty conditions raises some fire weather concerns today. Fortunately, temperatures today are cool and recent warmth and rainfall should be allowing for green-up of fuels across the area. Still, longer grasses may still be dormant, especially farther north, so caution is advised while burning.

The upper level trough that brought Friday's severe weather and today's cool, breezy conditions will continue eastward through this evening. Tonight into early Sunday morning, a secondary shortwave propagating through the backside of the broader flow pattern will bring a brief chance for light snow/rain to northern and northeastern Iowa. Model soundings depict a shallow saturated layer through the dendritic growth zone, as well as weak instability within that same layer. They also show a rather dry sub-cloud layer which will work to evaporate hydrometeors as they fall. That all said, it seems like we will be able to get precipitation down to the surface for at least an hour or two, albeit light. Depending on the time this occurs, precipitation could fall as either light snow or light rain. Regardless, any accumulations will be minimal.

As indicated by the potential for light snow in northern Iowa, temperatures will drop near freezing overnight tonight. Below freezing temperatures will be most likely over northern Iowa, while areas central and south will be near or slightly above freezing. Vegetation is likely most susceptible in the southern portions of the state, while areas that have been cooler in northern Iowa are less at risk from freeze. Likewise, dewpoints in the teens to twenties overnight and light winds will help to negate frost development. Therefore, have held off on any frost or freeze headlines tonight. Sunday night into Monday morning, however, looks like a slightly different story. The meteorological setup tomorrow night as the surface high moves overhead looks more favorable for radiational cooling, thanks to clear skies and light winds. Forecast low temperatures are in the low 20s to upper 30s, including over areas with susceptible vegetation. Therefore, tomorrow night looks like a better candidate for a widespread freeze, assuming skies remain clear.

LONG TERM /MONDAY THROUGH SATURDAY/

Issued at 227 PM CDT Sat Apr 18 2026

500 mb ridging over the western half of the CONUS will generally control the weather pattern through the beginning of next week, putting the state in a northwest flow regime through Monday and Tuesday before the ridge passes overhead on Wednesday. Return flow on the backside of Sunday's high will advect warmer temperatures up into the area Monday through Wednesday, resulting in unseasonably warm conditions through the first part of the week. Persistent access to gulf moisture will be lacking through this period, although we do get a few periods of some better moisture transport which may allow for light precipitation chances by mid-week. However, for most of the area, this period looks warm, dry and breezy.

Later in the week, the ridging will be pushed off to the east in lieu of a broad 500 mb trough. This will bring a healthier push of gulf moisture, as well as synoptic support for more thunderstorms Thursday into Friday. The synoptic setup would certainly suggest severe weather will be possible, as is supported by NSSL and CSU machine learning probabilities for severe weather. However, it's a bit early to be putting stock in the environmental conditions. Most importantly, active weather looks to return Thursday into Friday of next week.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 616 PM CDT Sat Apr 18 2026

VFR conditions will prevail through the TAF period. Gusty WNW winds this evening will diminish after sunset, then pick up again during the day Sunday. A few brief light showers and MVFR ceilings are possible at MCW and ALO on Sunday morning, roughly around 12Z, however the probability of such impacts at either site is low (<30%) and thus not mentioned in the 00Z TAFs.

DMX WATCHES/WARNINGS/ADVISORIES

None.