textproduct: Des Moines

KEY MESSAGES

- Red Flag Warning in the southwest today for critical fire weather conditions. Near-critical conditions near the warning area.

- High Wind Warning for gusts 60+ mph tonight. High Wind Watch issued south for possible expansion today.

- Significant winter storm will impact the region Sunday. Northern Iowa has the highest confidence in local impacts at this time, with the highest impacts still residing in Minnesota and Wisconsin.

UPDATE

Issued at 1024 AM CDT Thu Mar 12 2026

Confidence is increasing in winds nearing or reaching advisory criteria across southern Iowa beginning this afternoon. There will likely be three periods of relatively surging winds in this area. The first will come in the early to mid-afternoon. The second will come this evening, when the strongest gusts may be recorded as the strongest pressure gradient moves through the area. The third will come behind the passing trough overnight. Although there may be relative lulls between these periods, felt it prudent to cancel the High Wind Watch and replace it with two Wind Advisory segments for all counties south of the Interstate 80 corridor, beginning this afternoon.

No changes have been made to the High Wind Warning or Red Flag Warning at this time.

SHORT TERM /THROUGH SATURDAY/

Issued at 353 AM CDT Thu Mar 12 2026

Overnight objective analysis showed dew points in the low 20s just across the Missouri River. As the surface ridge pivots away, this dry air will begin to leak into Iowa along the strong southwest flow that sets up today. No expansion to the Red Flag Warning overnight as cloudiness will limit some of the afternoon mixing in the area today. That being said, RH values near the existing warning may still drop below 30% today and gusts over 30mph will be common. Burning in and near the warning area is highly discouraged today. Trends will be monitored for potential expansion this afternoon.

The other story in the short term is the winds themselves, especially as we move into tonight. Winds in the afternoon will be borderline Wind Advisory in the south. This is in response to the enhanced low-level jet ahead of the deepening low in North Dakota and into northern Minnesota. The warm sector wind max will be over 40kts in the afternoon and increase to near 60kts overnight. Lift, cloud cover, and WAA will combat momentum transfer here, so have refrained from a Wind Advisory for now. Still, it's possible that gusts over 40mph will occur this afternoon, mainly across the southern half of the state. The stronger winds come with a passing cold front tonight. While it will shove the warm sector jet away, the wind max associated with the parent low will park over the northern half of the state after sunset. Meanwhile, the CAA and pressure rises from subsidence point to very windy conditions overnight. Some of the model soundings tonight have favored an initial push of high winds with the front followed by a more sustained period of winds after 06z with a secondary push of CAA. The inversion simulated in between is shallow and will also be fighting the density push of rain-cooled air, so not currently expecting much reprieve. The wind max and pressure gradient move out by late morning Friday. No changes made with the High Wind Warning on this issuance, but have expanded the High Wind Watch further south to capture the anticipated effects of the evening fropa. Uncertainty remains in how strong winds will be as southern Iowa sits far from the winds max and tighter pressure gradient. Best case, the watch is replaced with an Advisory later. Nonetheless, winds of this speed will meet the caliber winds of a severe thunderstorm and bring a risk of damage to trees and power lines. 70mph wind gusts are not out of the question in northern Iowa, particularly as the front passes.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

Issued at 353 AM CDT Thu Mar 12 2026

A significant winter system is forecasted for this weekend. A seasonally strong upper-level jet max will intensify off the coast of the PNW early Saturday and begin to quickly deepen a trough residing over the Rockies. Trends over the last 24 hours have been a slightly southern shift as the jet will dig deep, generating height falls on the order of around -25 dam by Sunday night. Thermal ridging ahead of time will advect in above freezing surface temperatures over at least the southwest half of the state. The warm sector in southern Iowa will be convective to start the day. A warm layer exists aloft for much of the state to start and could offer a transition from rain to freezing rain until the warm layer is ushered out by the dynamic low. The transition to snow looks to occur Sunday afternoon. An intense band of snow will set up somewhere in Northern Iowa and into Southern Minnesota (this region will have almost all snow for this event) then heavy snow will set up on the backside of the low. With this continued snow will be high winds pushing similar values to Thursday night. The most notable difference between the GFS and Euro camps is when the TROWAL will form (culprit of the west flank snow) with the Euro offsetting this precip axis into eastern Iowa and northern Illinois. A solution such as the GFS brings that heavy snow over Iowa instead, bringing most of the area into play for Winter Storm impacts -- some potentially significant. At this time, confidence is highest in the northern band of snow that sets up early and there will likely be watches hoisted to account for this portion of the event. Monitoring trends closely for central and southern Iowa. Anticipate significant travel impacts in the region Sunday.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1239 PM CDT Thu Mar 12 2026

Winds are breezy out of the south to southwest today, although cloud cover has generally kept the strongest gusts at bay at TAF sites. Expect winds to continue to increase through the afternoon, with gusts around 30kts possible at times, especially in southern and western Iowa. A system moving through this evening will first bring rain chances to the area, mainly over northern Iowa near KFOD, KMCW and KALO, although at least light rain could be observed at KDSM and KOTM this evening as well.

Following the rain, a wind shift to northwesterly will be accompanied by extremely windy conditions. Sustained winds of 30 to 35 kts are likely with gusts around 40 to 50 kts possible at times. Winds will be strongest in northern Iowa near KFOD, KMCW, and KALO, but 40+ kt gusts are possible at all sites tonight. Low level wind shear will also be present for a few hours as the winds shift from southwesterly to northwesterly, but should end as surface winds increase behind the boundary. Strong winds overnight into early Friday morning will then diminish around mid- day Friday.

DMX WATCHES/WARNINGS/ADVISORIES

High Wind Warning from 10 PM this evening to 7 AM CDT Friday for IAZ004>006-015-016-023>025-033>035-044>047-057>059. High Wind Warning from 10 PM this evening to 10 AM CDT Friday for IAZ007-017-026>028-036>039-048>050-060>062. Red Flag Warning until 9 PM CDT this evening for IAZ044-045- 057-058-070-071-081-082-092-093. Wind Advisory until 7 AM CDT Friday for IAZ070>072-081>083- 092>094. Wind Advisory until 10 AM CDT Friday for IAZ073>075-084>086- 095>097.