textproduct: Des Moines

KEY MESSAGES

- Strong winds will surge through the area this afternoon and evening, with gusts to 50 MPH in some areas. Snow will also fall mainly in the north and northeast, where both falling snow and snow already on the ground will blow leading to significant visibility reductions and dangerous travel conditions. Blizzard conditions will be possible at times!

- Farther south, toward central and southern Iowa, current snow cover is minimal and accumulating snow chances today are lower, so blowing snow is less of a threat. However, the strong winds will still make travel difficult at times.

- Very cold weather will dominate the region from Thursday night into Saturday and perhaps Sunday. Dangerous wind chills are forecast, with the lowest values likely coming around Friday morning.

DISCUSSION

Issued at 320 AM CST Wed Jan 21 2026

The surface low pressure system that moved across Iowa yesterday is now departing to the east. Low stratus clouds are spreading in from the northwest within broadly cyclonic 500 MB flow aloft, while surface winds are light and variable. Meanwhile, an energetic 500 MB shortwave is moving into North Dakota and will continue to sharpen this morning as it swing southeastward, crossing Iowa and Minnesota this afternoon. As it does so, it will pull a strengthening surface front through with it, which will cross our forecast area from roughly 12 PM (northwest) to 6 PM (southeast) today. A swath of frontogenetical forcing will accompany the passage of the system and in our northern and northeastern counties a few hours of relatively deep saturation will allow for a burst of snow around midday into the afternoon, with a quick accumulation of around an inch expected. During or right on the heels of this snow burst, very strong winds will surge in from the northwest. Model output almost unanimously depicts 40-45 KT 925 MB winds and strong cold air advection behind the surface front, with downward momentum transport aided further by the frontogenetical circulation and sustained into this evening by rapid high rises behind the system. Forecast soundings indicate top-of-mixed-layer winds around 50-55 KT for several hours this afternoon and steep lapse rates above the surface and this is a classic set-up for a high wind event. Adding to hazardous weather concerns is the potential for snow showers or snow squalls in the turbulent mixing/flow behind the front. Short-range models have backed off on squall potential somewhat tonight, with near-surface instability diminishing and the frontogenetical forcing being tied closely to the surging boundary. Forecast soundings also show moisture will be very limited in this region, and confidence in post-frontal snow showers has decreased. Forecast POPs are thus near 100% in our northeast early this afternoon, and around 30-50% right along the boundary farther south, but only 10-30% behind the front.

Across about the southern/southwestern half of our service area where snow cover is minimal and anticipated snowfall today is minimal, the primary threat today will be the strong winds and a Wind Advisory has been issued accordingly. Farther north there is already powdery snow cover from yesterday (and earlier), and another inch or so is expected today, so when the strong winds hit the impacts will be more severe. Blowing of both falling snow and previous snow will greatly reduce visibility at times and snow-covered roads and strong crosswinds will make travel dangerous. A Winter Weather Advisory has been issued for these areas, however, blizzard conditions are entirely possible and an upgrade to a Blizzard Warning may be needed later today.

Aside from today's hazardous weather in Iowa, the large gyre that has been centered near Hudson Bay, Canada for the last several days and responsible for our cyclonic steering flow is finally beginning to eject this morning, partially due to the pull of the strong shortwave responsible for our forthcoming strong winds and snow, and will swing southward into southwestern Ontario by Thursday. As it does so, a large Arctic high pressure area will be pushed from Canada southeastward into the Upper Midwest and Iowa. The leading edge of this airmass, accompanied once again by gusty northwest winds (though not as strong as those today), will cross our area Thursday afternoon with the large high building in for several days thereafter. The result will be a period of intense cold across the region, initially with breezy conditions late Thursday/Thursday night, then with lighter winds but even colder temperatures as the high pressure settles nearby. On both Friday morning and Saturday morning temperatures will fall below zero statewide, and even during the day on Friday will likely remain below zero except in the far south. A prolonged period of dangerous wind chills will result, with the lowest values likely late Thursday night/Friday morning when winds are higher. The Extreme Cold Watch in effect during this time has been expanded across our entire forecast area, with at least part of the area likely to upgrade to a warning later today or tomorrow.

At the end of the week the gyre over Ontario will move away eastward toward the North Atlantic, and in its wake another 500 MB trough is set to swing across much of the U.S. this weekend into early next week. This system will be different however, in that long-range models unanimously split it into northern and southern components that are not well-phased. The southern stream component of the trough is set to produce severe winter weather impacts across a large swath of the southern U.S. and it remains to be seen whether the northern edge of its precipitation shield will make it up into Iowa, or be held to the south by the Arctic surface high pressure in place in our region. At this point it appears that the strength of the high will be sufficient to shunt the precipitation to our south, and while the northern stream trough will move through and provide some forcing for ascent that could also provide a mechanism for precipitation, the low-level dry air in place should mitigate that potential as well. As such, a dry forecast is maintained during this time.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1139 AM CST Wed Jan 21 2026

A strong cold front will move through Iowa this afternoon and will bring strong and gusty northwest winds that may approach 50 kts at times. Snow and blowing snow may create near blizzard conditions with vsbys < 1/4sm at KMCW/KALO later this afternoon and early this evening. Snow showers may extend as far south as KDSM. The wind will gradually diminish from mid evening on and will be much lighter by the end of the forecast period. Some sct MVFR conditions may linger after 06z along with some light snow.

DMX WATCHES/WARNINGS/ADVISORIES

Blizzard Warning until 11 PM CST this evening for IAZ004>007- 015>017-023>028-038-039. Extreme Cold Watch from late Thursday night through Saturday morning for IAZ004>007-015>017-023>028-033>039-044>050-057>062- 070>075-081>086-092>097. High Wind Warning until 11 PM CST this evening for IAZ033>037- 044>050-057>062-070>075. Winter Weather Advisory until 11 PM CST this evening for IAZ034>037-050. Wind Advisory until 2 PM CST this afternoon for IAZ048-049- 060>062-073>075. Wind Advisory until 8 PM CST this evening for IAZ081-082-092. Wind Advisory until 11 PM CST this evening for IAZ083>086- 093>097.