textproduct: Des Moines

KEY MESSAGES

- Dense Fog Advisory in effect through Noon. Another one may be needed tonight.

- Winter Storm Watch for Blizzard Conditions issued for portions of northern Iowa. 45+ mph winds will cause blowing snow leading to reduced visibilities.

DISCUSSION

Issued at 333 AM CST Sat Dec 27 2025

Dense fog continues this morning and continued WAA will enforce more fog and stratus through the day Saturday, especially north. Highs will be in the 40s and 50s. Another Dense Fog Advisory will likely be needed this evening and tonight. Southern Iowa will begin to see rain from the incoming system, its trough axis ushering in CAA and a transition to snow in the northwest by the end of the night.

There is increasing confidence in significant travel impacts for the region for much of Sunday and Sunday night, leading to concerns for post Christmas travel. A notable change this package was the issuance of a Winter Storm Watch for Blizzard conditions, including northern and northeast Iowa. This is due to the significant intensification of the winter storm, the main synoptic feature deepening as it crosses MN (seen best by very strong Q vector convergence). This means that QPF and winds have both trended up. Snowfall amounts up to 4 inches will be possible along the IA-MN border. It won't be the amounts that drive the impacts, instead the blowability of the snow. Winds and gusts at Advisory criteria will be common in the watch area, strengthening as the jet speed eclipses 50kts on Sunday night. This will prolong impacts from blowing snow long after it falls. The HREF supports thinking for blizzard conditions as it has a 60% chance to see visibility under 1/4 mile in northern Iowa. Expansion of headlines is possible, but started tonight where the snowfall duration would be the least transient. Highest confidence in impacts is north of Highway 20. If you have plans to travel north into Minnesota this weekend, it's worth monitoring the forecast for updates and adjusting your travel plans accordingly.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 545 AM CST Sat Dec 27 2025

LIFR vsbys and cigs will become IFR later this morning. Improvement to MVFR/VFR expected briefly this afternoon for all sites but KMCW and KALO where fog will keep restrictions in place. Fog again enters the picture tonight and will likely be dense (IFR/LIFR) but will be broken up in the south due to rain.

DMX WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until noon CST today for IAZ004>007-015>017- 023>028-033>039-044>050-057>062-070>075-081>086-092>097. Winter Storm Watch from Sunday morning through late Sunday night for IAZ004>007-016-017.