Marine Weather and Tide Forecast for Yankton, SD

DISCUSSION
Issued at 318 PM CST Mon Dec 8 2025

Low level stratus and fog persists across the area this afternoon.
The fog is being driven by weak southerly moisture advection, keeping the boundary layer saturated. The stratus and fog have begun to nudge eastwards as low level winds begin to take on a more westerly component thanks to an advancing warm front. Thus, have left the Dense Fog Advisory in effect through 10 pm for locations along and east of I-29. Trends will be monitored through the rest of today to see if any further reductions are needed in the Advisories extent. Tonight will be quiet with low temperatures falling to the 20s to up to about 30F.

Things begin to change on Tuesday as a strong upper level shortwave trough pushes through the Northern Plains. This will bring a round of precipitation to the area beginning Tuesday morning. Precipitation looks to begin as light freezing rain before transitioning to plain rain as temperatures warm through the morning hours, thanks to persistent warm air advection (WAA) aloft. A few places might see a light glaze of ice for a brief period of time during the morning and early afternoon hours before plain rain melts away the ice. The afternoon will still see some cooler temperatures across the area thanks to persistent cloud cover and current snowpack across the majority of the area. Have highs only warming to the mid 30s east of the James River up to the 40s and 50s west of the River. The bulk of the rain will push east of the area by the late afternoon hours. The other component to Tuesday will be strengthening winds during the afternoon hours as a strong cold front will pushes through the area.
A strong shot of cold air advection (CAA) is expected with the passing front, resulting in very strong winds across the entire area. The strongest winds will come during the evening and overnight hours where gusts up to 50 to 60 mph is likely (>=70% chance). These strong winds will be capable of blowing the current snow pack around which can result in blowing snow across most of the area. The main uncertainty regarding the extent of the blowing snow is due to the previously mentioned rain and temperatures warming above freezing.
The rain and warmer temperatures will likely melt some of the snow pack. Even with the quickly falling temperatures behind the front, questions remain how blowable the snowpack will be. As such, have issued a Winter Storm Watch for Blizzard Conditions from noon on Tuesday through noon Wednesday. A High Wind Warning has been issued for Gregory, Charles Mix, and Brule counties due to these counties having a much lower snowpack to non existent snowpack. The High Wind Warning is in effect from noon Tuesday through 3 am Wednesday.

Winds will be weakening during the morning hours on Wednesday as high pressure slides through the Northern Plains. Tuesday will be the last "warm" day across the area before a much colder airmass settles into place for the rest of the week. Highs will be below average in the 20s to down to the teens and single digits come Friday through the weekend. With such cold temperatures in place along with light winds in place, Cold Weather headlines may be needed. Highs may trend back towards seasonable come early next week.

For precipitation chances, there looks to be persistent chances for snow throughout the week. Currently, the highest chances (30-40%)
for snow looks to come on Thursday. Though additional chances will persist through the weekend. Given how these are all clipper systems, light snowfall is most probable with each passing clipper at this time.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
Issued at 551 PM CST Mon Dec 8 2025

Low stratus and patchy dense fog covers much of the region from the I-29 corridor and east. Here IFR to LIFR ceilings will continue for the next few hours before relatively warmer and drier air pushes in from the west clearing stratus and fog.

Around mid-morning a storm system will move into the area from the northwest. For areas along and north of Highway 14 precipitation should begin as a wintry mix including freezing rain or drizzle. Ice accumulation, if any, is expected to be a light glaze to a hundredth of an inch. As the storm sinks further southeast precipitation will increase in coverage and transition over to all rain. By the early evening most of the rain will be located over southwest Minnesota and northwest Iowa. It will linger here for a few hours and will likely transition to snow before exiting after midnight.

Lightly breezy southerly winds Tuesday morning will become westerly then northwesterly as a strong cold front (associated with the previously mentioned storm) passes through the region. Winds will increase drastically over a short period of time. Gusts of 35-45 kts are expected west of the James River by early afternoon. Winds continue to increase as they progress east. By the end of the period, gusts of 40-50 kts are expected region wide. Strong winds continue into Wednesday. Some reductions in visibility due to blowing and drifting snow are likely. In addition, some LLWS is possible toward the end of the period, but confidence was too low to include at this time.

FSD WATCHES/WARNINGS/ADVISORIES
SD...Dense Fog Advisory until 10 PM CST this evening for SDZ040-055- 056-062.
Winter Storm Watch from Tuesday evening through Wednesday morning for SDZ067-070-071.
Winter Storm Watch from Tuesday afternoon through Wednesday morning for SDZ038>040-052>056-058>062-064>066-068-069.
High Wind Warning from noon Tuesday to 3 AM CST Wednesday for SDZ050-057-063.
MN...Dense Fog Advisory until 10 PM CST this evening for MNZ071-080- 081-089-090-097-098.
Winter Storm Watch from Tuesday evening through Wednesday morning for MNZ080-081-089-090-098.
Winter Storm Watch from Tuesday afternoon through Wednesday morning for MNZ071-072-097.
IA...Dense Fog Advisory until 10 PM CST this evening for IAZ001>003- 012>014-020>022-032.
Winter Storm Watch from Tuesday evening through Wednesday morning for IAZ001>003-012>014-020>022-031-032.
NE...Winter Storm Watch from Tuesday evening through Wednesday morning for NEZ013-014.