textproduct: Sioux Falls

KEY MESSAGES

- The fog just will not give up. Expect areas mostly east of I-29 to see a resurgence of fog tonight. Dense fog advisory out through 12z Sunday.

- Strong northerly winds will develop late tonight and continue into Sunday night. Gusts of 40 to 50 mph are likely during this time. Wind advisory for most areas near and west of I-29.

- Snow will develop on Sunday. Amounts have trended upwards a bit, about 1-2 inches with isolated higher amounts up to about 3 inches possible east of I-29. The strong winds with the falling snow will lead to some blowing snow across the area. Reduced visibility within the snow and blowing snow may create hazardous travel conditions. Winter weather advisory for southwest MN and northern parts of northwest IA.

- Much colder air will accompany these strong winds, leading to wind chill values of 10 below to 20 below zero, especially Sunday night into Monday morning.

DISCUSSION

Issued at 215 PM CST Sat Dec 27 2025

Tonight: A lead piece of energy moves into the area this evening and early overnight, but for now impacts are limited with this due to a fairly strong dry layer below about 750mb. If anything can develop, a little mixed precipitation will be possible with a warm layer around 900-800mb. Temperatures in most locations will be near or above freezing as well which will help limit the impacts. Later tonight the main wave and lift will push into central and southeast SD, leading to the development of a band of snow as well as an increase in surface winds. The band of snow should be approaching I- 29 by 11-13z Sunday morning. This band quickly shifts east into southwest MN and northwest IA on Sunday morning, then gradually ends by mid afternoon. The exception will be in southwest MN and particularly near and east of the Buffalo Ridge where snow could linger a little longer and some wrap around into the evening will be possible before the system exits. One tricky spot will be down I-29 where snow will fall from about 11z through 18z, but once the snow ends it is likely that the visibilities will improve, so that any location along this route may be limited to 3-4 hours of snow/blowing snow. A pocket of cold air aloft late afternoon/evening may allow snow showers in eastern SD but confidence for now is pretty low as temperatures in much of the layer fall colder than the DGZ and moisture appears a bit limited.

Otherwise some residual moisture in the boundary layer and lighter winds will lead to another night of fog, especially in northwest IA and nearby areas of SD and sw MN. This fog will linger to sometime between 9z and 12z tonight.

With the strong winds and influx of cold air, wind chills will fall to -10 to -20 Sunday night into Monday morning. Currently it does not look like a cold weather advisory will be needed.

Monday will be cold and breezy and high pressure slowly builds into the area. High temperatures likely in the teens most locations. Wind chills below zero are also expected into early afternoon.

High pressure moves through quickly Monday night with westerly flow developing on Tuesday. This will allow temperatures to climb to around or just above normal with highs in the upper 20s to mid 30s over any fresh snow and maybe some lower 40s near and west of the James River.

Northwest flow Wednesday through Saturday will likely allow for a few ups and downs on temperatures with limited potential for precipitation.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1120 AM CST Sat Dec 27 2025

A busy set of TAF's with fog, wind and snow all expected. While fog is waning a bit in southwest MN and northwest IA, it will likely surge back to the northwest this evening ahead of an incoming cold front. Areas east of I-29 will again see the best chance for visibilities of a half mile or less. From roughly 4z through 10z a strong cold front will drop southeast through the area. Some light mixed precipitation will be possible ahead of this front, but confidence is a bit low on this. Higher confidence comes behind the front where northwest winds will gust to 40 to 50 mph late tonight through Sunday afternoon as well as a band of snow expected late tonight through mid Sunday afternoon. Some blowing snow will also be possible. Widespread MVFR conditions are expected with the snow with pockets of IFR conditions.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Wind Advisory from 6 AM Sunday to midnight CST Sunday night for SDZ040-055-056-061-062-066-067-069>071. Wind Advisory from 3 AM to 9 PM CST Sunday for SDZ038-039-050- 052>054-057>060-063>065-068. MN...Dense Fog Advisory from 6 PM this evening to 6 AM CST Sunday for MNZ081-089-090. Winter Weather Advisory from 6 AM Sunday to 6 AM CST Monday for MNZ071-072-080-081-089-090-097-098. IA...Dense Fog Advisory from 6 PM this evening to 6 AM CST Sunday for IAZ001>003-012>014-020>022-031-032. Winter Weather Advisory from 6 AM Sunday to 6 AM CST Monday for IAZ001>003-012>014. Wind Advisory from 6 AM Sunday to midnight CST Sunday night for IAZ020>022-031-032. NE...Wind Advisory from 6 AM Sunday to midnight CST Sunday night for NEZ013-014.