textproduct: Des Moines

KEY MESSAGES

- Patchy to localized dense fog remains possible over northern Iowa through mid-morning before dissipating.

- Warming trend continues into the weekend, topping out on Saturday well above average values in 70s to 80s. Elevated fire weather conditions are expected.

- Brief cooldown on Sunday with recovering temperatures to start next week. Forecast looks largely dry into early next week.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 332 AM CDT Thu Mar 19 2026

Fairly quiet conditions are noted across Iowa this morning, with satellite imagery depicting recently clearing skies over the northern half of Iowa, while southern Iowa remains covered but should also clear out as clouds descend further out of the state over the next hour or so. This has resulted in a notable temperature gradient, with values in northern Iowa in the 30s to low 40s, while southern Iowa has values in the upper 40s to low 50s. Should see temperatures decrease and become a bit more uniform through sunrise, with lows through the 30s. Fog so far has been quite isolated but also inconsistent over northern Iowa, with areas such as Mason City bouncing between 1/4 to 3 statute miles in visibility, while other sites nearby have read values of 2-6 miles before returning back to 10 miles with no fog. Model soundings, especially the NAM, continue to show notable moisture trapped under the inversion that is covering the state this morning, but is likely a bit overdone as the snow cover over much of the area has largely, if not completely melted due to the above freezing temperatures. HREF guidance has backed off only slightly, with patchy fog still suggested over the northern half of Iowa, but with only isolated areas of dense fog near the IA/MN border where better moisture content is most likely to remain, peaking around or just after sunrise before dissipating mid-morning. Given the uncertainty on the extent of fog this morning, will be holding off on any potential headlines, though close monitoring will continue through the rest of the morning.

Northwesterly flow aloft over Iowa due to the building mid-level ridge over the northwestern CONUS will prevail today, and largely remain through the next few days, keeping the region on the dry side into the weekend. Mostly clear skies are expected, which will allow for temperatures to warm up quickly as highs reach into the 60s to low 70s, warmest southwest, though a bit cooler northeast in the 50s where lingering snowpack still remains but will continue to melt. A mid-level trough riding the prevailing ridging pattern is still expected to slide southeast into the Midwest late tonight into Friday morning, though should remain well north and east of Iowa as any forcing with this wave is indicated to largely reside over the upper Great Lakes region. However, could see the potential for fog again over portions of northern and eastern Iowa as CAM guidance is hinting at another overnight inversion and lingering moisture at the surface from snowmelt. This likely is already overdone as forecast temperatures today should get rid of any remaining snow in these areas and limit the extent of moisture that these models are trying to pick up on. Regardless, something to keep an eye through today. Overnight lows will fall into the 40s, highest south.

Surface high pressure slides into the region through Friday behind the aforementioned northeastern trough passage, which will keep conditions dry. Though winds will shift northwesterly for the day, the push of warmer air aloft around 15 C (paired with subsidence from the high pressure) and mostly sunny skies at least over the southwest half of the state will boost highs in the 70s, while cooler northeast where clouds are looking more likely keep values a touch cooler in the 60s.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 332 AM CDT Thu Mar 19 2026

As the area of high pressure departs into Saturday, will see a shift in low level winds increasing out of the southwest, which will bring a stronger push of warm air advection into Iowa ahead of the development of a broad area of low pressure over the western Central Plains. With the warm front well north of Iowa, dry conditions will prevail, with temperatures warming very nicely across the state through the day, as well above average values in the 70s in the northeast half of Iowa, and through the 80s in the southwest half are likely. Breezy southwest winds with the push of warm and dry air (RHs dropping in the 30s, lowest over southwest Iowa) and fuels still cured will result in elevated fire weather conditions, but should remain below headline criteria at this time. Burning is not recommended.

By Sunday, the center of the low pressure mentioned above looks to directly pass over Iowa to some degree, with the boundary dropping southeastward across the Northern Plains. There are some differences in the track of the warm front and therefore potential rain that could come with this. The NAM and Euro favor at least some light rain over northern Iowa while the GFS trends on the dry side. Winds shift northwesterly through Iowa Sunday morning as cold air advection pushes across the state, which will cool temperatures through the morning. This means a non-diurnal trend in temperatures at least over northern Iowa, so warmest temps in the early morning and decreasing through the day. A large range in temperatures are expected, with highs in the upper 40s to 50s north and in the 60s to low 70s south. Dry conditions remain into the start of the next work week as high pressure sinks across the region.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 642 AM CDT Thu Mar 19 2026

Localized dense fog over KMCW will continue at times over the next few hours, leading to periods of reduced visibilites below a mile. Patchy fog is expected otherwise at KFOD and KALO, but should lift by mid-morning, with minor visibility restrictions. Otherwise, mostly clear skies are expected, with VFR conditions expected to return across all terminals. Winds out of the north/northwest will be light, then shifting south/southwesterly this evening into Friday and increasing.

DMX WATCHES/WARNINGS/ADVISORIES

None.