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.

- Light rain this evening through tonight will change over to snow Tuesday and continue into Tuesday evening. Probability of 4 inches of snow is 40 to 80% along and north of a line from Aberdeen to Ortonville, highest over the Sisseton Hills. Over the northern portions of the Sisseton Hills, there is a 50 to 60 percent chance of snow amounts exceeding 6 inches. Drifting and 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 526 PM CST Mon Nov 24 2025

Forecast remains on track this evening. No major changes planned.

SHORT TERM /THIS EVENING THROUGH TUESDAY NIGHT/

Issued at 341 PM CST Mon Nov 24 2025

The main concern in the short term will be the rain changing to snow on Tuesday with accumulating snow over portions of north central through northeastern SD into west central MN. There is still a quite a bit of uncertainty on where the heaviest snow could fall (especially along ND/SD border) due to exact track of the low between the different models. A track more north would mean less snowfall over our northern CWA and vice versa. Also it depends on the changeover time, a faster changeover would lead to higher snow amounts or if snowfall rates per hour become higher than forecasted Luckily this is quick moving system. The other concerns will be the highs winds causing for blowing and drifting snow.

By 00Z Tuesday, the upper level shortwave's axis extends through the middle of MT and southward into northwestern WY where it will continue to track east overnight and deepen. By 12Z Tuesday, the axis will extend through the central Dakotas with the trough continuing to track eastward with the CWA on the backside of this wave by Tuesday evening/Wednesday morning as this wave till continue to deepen as it continues to track eastward into MN/WI through Wednesday. GEFS continues to be a bit stronger on this wave compared to ENS/GEPS at this time. Down at the surface, the center of the ~1006mb low will hover over SD/WY border this evening with GEFS a bit further west than the other models with its center over eastern/northeastern WY. Through the overnight this low will track eastward across the ~southern half of SD with the center of the low over ~southeastern MN by 12Z Tuesday. The CWA will be to the west of the low and east of the high with this high moving in over the region Tuesday evening into Wednesday morning.

With the track of this system, latest CAMs/NBM agree really well on the overall timing of the precip. They indicate rain moving in over north central SD late this evening into tonight and spreading east/southeastward over the CWA with the precip transitioning to snow through Tuesday as CAA filters in on the backside of this system. It also looks like we could see a brief dry period, per dry slot, over portions of central SD Tuesday early morning to late morning before the backside of the system (snow) pushes through. It does look like the last of the snow/wrap around will exit our far eastern CWA between 03-06Z Wednesday (Cams model depending). All the Cams/NBM do indicate the heaver snow will stay up in ND/MN but still clipping our far northeastern CWA, being on the southern edge of the potential heavier snow band. HREF snowfall rate generally a quarter to half inch per hour along the ND/SD border with the possibility of up to an inch per hour over the Coteau There is still quite a bit of uncertainty between the models on exact snowfall amounts given the exact track of the low and where the band of higher snowfall ends up. Generally 2 to 5 inches in snow accumulation is possible over northern to northeastern SD (along the ND border) with higher amounts of 6 to potentially 8 inches of snow over the Coteau. Snow amounts decrease further south in the CWA, closer to the center of the low. There is about a 3 to 4 degree spread in the NBM 25-75th due to differences in overall snow amounts between models with the 75th percentile ranging from 4 to 8 inches along the ND/SD border into MN. If we see a more southward track/heavier snow band and higher snowfall rates, the higher elevation of the Coteau could receive up to 8-9 inches (90th percentile aka 10 percent chance). So to summarize, probability of 4 inches of snow is 40 to 80% along and north of a line from Aberdeen-Ortonville, with the percentage increasing further north of this line and highest over the Coteau. Over the northern portions of the Sisseton Hills, there is a 50 percent chance of snow amounts exceeding 6 inches.

Due to the CAA filtering into the low along with a steep pressure gradient and pressure rises, winds will increase out of the northwest with gusts of 30 to potentially 60 mph, highest over south central SD. EC EFI highlights this well with values of 0.7 to 0.8 over central SD with a shift of tails of zero. Luckily the highest winds are offset from where the heaviest snow could fall. However, the combination of falling snow and gusty winds up to 45-50 mph could lead to drifting and blowing snow (especially over/along the Sisseton Hills) resulting in visibility reductions over portions of north central through northeastern SD into west central MN. With expected snow accumulations and the combination of the potential for blowing snow, a Winter Weather Advisory has been issued from Corson County and eastward through west central MN. South of here through east central SD, a Wind Advisory has been issued with a High Wind Warning over south central SD where we expect our highest winds to gusts. Over south central SD, the combination of dry fuels and these wind gusts potentially reaching 60 mph leads to high to very high grassland fire danger index.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 341 PM CST Mon Nov 24 2025

The long term period starts Wednesday morning with an upper level low off to our east over WI/MI. This will continue to move east and another area of low pressure moves onto the Pacific Coast of Washington/British Columbia. This will dive south and a trough out of Canada will move across the area Saturday. This will kick off a parade of troughs moving out of Canada through the end of the period. The first lower level low moves across the forecast area Friday or Saturday (models disagree on exact track and timing - some move across southwestern SD Friday afternoon, others move across more central SD on Saturday). Once this moves out, it looks like high pressure moves in, although the GFS has another low move across the area Sunday night into Monday.

Due to model uncertainty, snow totals for Friday/Saturday are a bit uncertain. Right now, it looks like snow totals will be generally less than an inch with the probability of more than an inch in 24 hours ranging from about 30-40%. This is slightly higher than previous runs. Once the models decide on a track for the low, confidence should increase on snow totals and the area for heaviest snow. At the moment, the GFS deterministic run looks a little more banded than the other models, and if that solution occurs then snow totals may be a little higher. Also at the moment, the EC and GFS deterministic models have the heaviest snowfall mainly over central SD.

Temperatures during the period are going to be about 10-15 degrees below normal for this time of year, a big change from the last several weeks. The air behind the early week low is much colder and we get several shots of CAA through the weekend. Other than some residual gustiness (around 30 mph, which could result in some blowing snow) on the eastern side of the Prairie Coteau Wednesday morning, winds don't look to be out of the ordinary.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1116 PM CST Mon Nov 24 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will fall to IFR vsby and cigs as a fast moving clipper brings moderate snow, strong northwest winds and blowing snow to the region. Conditions will improve west to east Tuesday evening.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Winter Weather Advisory from 3 AM CST /2 AM MST/ to 6 PM CST /5 PM MST/ Tuesday for SDZ003>005-009-010.

Winter Weather Advisory from 6 AM Tuesday to midnight CST Tuesday night for SDZ006-011.

Winter Weather Advisory from 6 AM Tuesday to 6 AM CST Wednesday for SDZ007-008.

Wind Advisory from 6 AM CST /5 AM MST/ to 6 PM CST /5 PM MST/ Tuesday for SDZ015>017-034>037.

Wind Advisory from 9 AM to 6 PM CST Tuesday for SDZ018-019.

Wind Advisory from noon to 8 PM CST Tuesday for SDZ020>023.

High Wind Warning from 6 AM CST /5 AM MST/ to 6 PM CST /5 PM MST/ Tuesday for SDZ033-045-048-051.

MN...Winter Weather Advisory from 9 AM Tuesday to 6 AM CST Wednesday for MNZ039-046.