textproduct: Aberdeen

KEY MESSAGES

- Winter conditions arrive Tuesday, with strong northwesterly winds and snow for many locations. Below normal temperatures are also expected through the beginning of December, with below zero wind chills possible over northern South Dakota.

- Rain Monday night (70% chance) will transition to snow Tuesday morning. The snow will fall light to moderately at times over northeast South Dakota and west-central Minnesota on Tuesday afternoon before ending Tuesday night. There is a 30 percent chance of 2 inches of snow or greater north of a line from McIntosh and Mobridge to Redfield and Watertown, and a 60 percent chance or greater over far northeastern South Dakota and west central Minnesota. The highest amounts expected over Marshall County. Patchy blowing snow will be possible Tuesday into Tuesday evening over north central to northeastern South Dakota and west central Minnesota.

- Winds will increase out of the northwest overnight through Tuesday, with gusts of 30 to 50 mph. The strongest winds will be over south central South Dakota, where gusts near 60 mph are forecast. Portions of south central South Dakota will jump to the very high Grassland Fire Danger Index values Tuesday afternoon.

UPDATE

Issued at 1135 AM CST Mon Nov 24 2025

Updated for 18Z Aviation Discussion below.

UPDATE Issued at 1022 AM CST Mon Nov 24 2025

Per radar returns, I did add in sprinkle mention for portions of south central through eastern central SD over the next couple hours. Otherwise, no changes made to the forecast.

SHORT TERM /TODAY THROUGH TUESDAY AFTERNOON/

Issued at 420 AM CST Mon Nov 24 2025

Today is the calm before the significant change to our overall weather. The current surface weather map shows low pressure over Ontario with a cold front sining across roughly the northern half of South Dakota. after a brief increase in winds behind the front winds will diminish to around 10 mph or less for the rest of the day. Low pressure over MT and WY will move over western SD by 03Z this evening as light rain begins over central SD. The rain will expand to the rest of the forecast area overnight. Falling temperatures will break a rain and snow to portions of northern SD already by 12Z Tuesday, with snow being the predominant weather type by 18Z for all but west central MN. The surface low will track to eastern SD by 12Z Tuesday and deepen across southern MN by 18Z and WI through the rest of the daytime hours. A tightening pressure gradient and plenty of cold air advection will result in strong winds over much of the area.

Winds will increase out of the northwest overnight through Tuesday, with gusts of 30 to 50 mph (lightest over west central MN). The strongest winds will be over south central South Dakota, where gusts near 60 mph are forecast. As a result, a High Wind Warning has been issued for Stanley, Jones, and Lyman Counties. Portions of south central South Dakota will jump to the very high Grassland Fire Danger Index values Tuesday afternoon despite relative humidity values in the 60 to 70 percent range, as little no no precipitation is expected there.

Unfortunately precipitation wise, there is still a lot of variability in forecast solutions. The highest snowfall amounts for this storm have shifted slightly farther south over the Northern Plains. Given the uncertainty, the Winter Storm Watch over portions of ND and northern MN has been expanded to include Marshall, Roberts, and Traverse Counties of northeastern SD and west central MN. Heavy snow is possible. There is a 50 to 70 percent chance of at least 4 inches of snow. The highest snowfall amounts are expected over Marshall County and northwestern Roberts County. Winds could gust as high as 40 mph Tuesday afternoon and evening, which will result in reduced visibilities in blowing and potentially drifting snow.

Elsewhere, there is a 30 percent chance of 2 inches of snow or greater north of a line from McIntosh and Mobridge to Redfield and Watertown. Patchy blowing snow will be possible Tuesday into Tuesday evening over north central to northeastern South Dakota and west central Minnesota, with any drifting snow dependent on how much snow falls.

LONG TERM /TUESDAY EVENING THROUGH SUNDAY/

Issued at 420 AM CST Mon Nov 24 2025

Snow is forecast to move out of eastern SD, southwest MN, and northwest IA Tuesday night, with some patchy areas of blowing snow having to potential to continue into Wednesday morning over northeastern SD. In the upper-level, northwest flow will be over the area Wednesday and Thursday, which will continue to advect cold air through the atmosphere into central and eastern SD, northeast NE, southwest MN, and northwest IA. This CAA will cause temperatures to drop to be 5-10 degrees below normal by Thanksgiving and stay cold through the weekend. At the surface, high pressure is forecast to move over the area Wednesday and stay through the day Thursday, helping to keep precipitation out during that time. The stronger winds Tuesday will slowly move over eastern SD, southwest MN, northeast NE, and northwest IA Tuesday night while decreasing its speed. The winds will continue to decrease through the day Wednesday, though some stronger wind gusts along the eastern edge of the Prairie Coteau from some downslope winds and to the east could be a bit stronger. There is a 30-60% chance for winds to gust over 30mph overnight into Wednesday morning over and east of the Prairie Coteau (highest long in northeastern SD along the eastern edge of the Coteau). By the afternoon, the probability for gusts over 30mph decreases to 20-40% before dropping off after sunset over eastern SD, southwest MN, and northwest IA.

Starting Thursday night/Friday morning, things become a bit more uncertain as there is a lot of variability in the models. Thursday night into Friday morning, some of the models are showing a line of WAA aloft on the back side of the high pressure. This WAA looks to help with the development of a band of snow that then moves over central and eastern SD, northeast NE, southwest MN, and northwest IA during the day Friday. As with the nature of banded snow event, there is a lot of variability in location and track of the band as well as snowfall amounts. After the band of snow moves through, the variability continues in the models, as some have shortwaves that push more snow through the area during the weekend and other models don't. An eye will need to be kept on this time to see if future model runs decrease uncertainty for these events as there could be many traveling after Thanksgiving that could be impacted.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1135 AM CST Mon Nov 24 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will remain in place for the first half of the TAF period as a high pressure ridge moves east across the area. Then focus turns to the winter weather system that will quickly move east across the area late tonight into Tuesday. Expect an initial period of rain before turning to snow tomorrow morning. The heaviest precipitation will be across northern SD and hit the lowest ceilings/visibilities in that area. With the strong northwesterly winds behind the low and falling snow, feel that sub 1SM vsbys are possible at KABR and KMBG. The snow will come to an end from west to east during the afternoon and evening hours on Tuesday.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Winter Storm Watch from Tuesday morning through late Tuesday night for SDZ007-008.

High Wind Watch from Tuesday morning through Tuesday afternoon for SDZ033-045-048.

MN...Winter Storm Watch from Tuesday morning through late Tuesday night for MNZ039.