textproduct: Aberdeen

KEY MESSAGES

- Patchy to dense fog will linger over portions of far northeastern South Dakota and west central Minnesota this morning, with visibility down to 1/4 mile at times. Temperatures below freezing could create pockets of freezing fog with icy surfaces.

- After above normal temperatures this afternoon, they will fall into the teens to single digits above zero Sunday morning through Monday evening.

- Winds out of the north to northwest will gust around 40 to around 50 mph late this evening through the day Sunday.

- Snow of around a half inch to 2 inches is forecast east of a line from Eureka and Highmore late tonight through Sunday morning. The strong winds and light falling snow may result in blowing snow with visibilities down to around a half mile at times.

- Elevated fire weather concerns are forecast Sunday over portions of central South Dakota, with grassland fire danger index values in the high to very high categories.

SHORT TERM /TODAY THROUGH SUNDAY NIGHT/

Issued at 548 AM CST Sat Dec 27 2025

The current surface weather map shows 998mb low pressure set up across the western half of ND. The low will slide along the ND/SD/MN border between 15-18Z today and exit our forecast area completely by 21Z. A tight pressure gradient will then form behind the low and associated cold front and 1040mb over Alberta/Saskatchewan.

Patchy to dense fog will slowly improve this morning over portions of northeastern South Dakota and west central Minnesota. Freezing fog, with a light icing on sidewalks and roadways, will improve as temperatures rise above freezing by mid morning. Visibility in dense fog will be down to 1/4 mile at times.

Temperatures will still be able to rise into the upper 30s and 40s across the forecast area this afternoon, with 50s common south of a line from Pierre to Miller. We won't realize similar temperatures until at least Tuesday of next week.

Strong winds out of the north to northwest will develop after 00Z, with winds shifting out of the northwest and remaining strong through the day Sunday. Wind gusts of 40 to around 50 mph are expected late tonight through the day Sunday, with 2 main blasts of strong winds. A Wind Advisory has been posted for much of central South Dakota tonight through the day Sunday. This may get expanded to include much of the rest of the forecast area for Sunday, depending on the latest trends.

Much colder air will also sink in, along with light snow. Freezing drizzle can't be ruled out over the Prairie Coteau and east late this evening into the early overnight hours, prior to the light snow falling. We continue to have patchy fog in the forecast for much of that area.

The strong winds and light falling snow early Sunday will result in drifting and blowing snow with visibilities briefly down to around a half mile at times. The highest snow amounts of around a half inch to 2 inches are east of a line from Eureka and Highmore. Overall precipitation for this next round of snow has doubled, but remains at around 0.10" or less (highest over the western slopes of the Prairie Coteau and our far eastern forecast area. Cold air rushing in will result in snow to liquid ratios increasing to around 10:1 late this evening to closer to 15:1 by daybreak Sunday. We'll need to monitor the latest trends on precipitation/snowfall amounts. At this point a 2-5 hour period of blowing and drifting snow is forecast when the snow passes. If this lasts longer or winds are stronger, with more significant reductions in visibility, additional winter weather headlines may be needed.

Grassland fire danger index values will reach the high to very high categories Sunday. Any snow will act to limit fire weather concerns, so expect changes. Relative humidity values fall into the 45 to 55 percent range in this area, while greater than 60 percent over northeastern SD and west central MN.

Wind chills will fall to -10 to -20F northwest of a line from Pierre to Aberdeen Sunday morning, and -10 to -25F for much of the area Sunday night as surface temperatures fall into the single digits above zero.

LONG TERM /MONDAY MORNING THROUGH FRIDAY/

Issued at 453 AM CST Sat Dec 27 2025

By Monday morning, the surface low pressure has move to the east of SD and an area of high surface pressure is starting to move into the state. There continues to be a tight pressure gradient over eastern SD and west central MN, which will continue to cause stronger winds to gust Monday morning and decrease through the day. There is a 30- 80% probability for wind to gust greater than 30mph around 6am Monday east of the Missouri River, with the highest chances over and east of the Prairie Coteau. These chances decrease through the morning so that there is only a 30-50% chance for greater than 30mph gust along the eastern edge of the Coteau around noon and less in the afternoon.

The upper-level pattern shifts Monday, with northwest flow staying over SD through most of the week as a ridge stays over the west coast and the upper-level trough continues to move east. Warm air starts to advect into SD Monday, which will help to warm temperatures slightly. Temperatures will go from being 5 to 15 degrees colder than normal Monday to 5 to 15 degrees warmer than normal Tuesday, with max temperatures going from the low teens into the 20s Monday to the 30s and 40s on Tuesday. The high surface pressure slowly moves out overnight, and around the same time and into Tuesday, a surface low pressure moves southeast from Manitoba into MN. Models are showing that the precipitation from this low should stay out of central and northeastern SD, though if the track of the low shift slightly to the west, then some precipitation could glance the area.

Tuesday evening into Wednesday, a cold front attached to the back side of this surface low is forecast to move through SD. Models are showing that snow will develop along this frontal boundary as it passes over SD, though models vary the location and intensity of the snow as the front moves through. This variability in the models lowers the confidence in the timing of the line of snow and its amounts. This will need to be watched as future models runs come in. Temperatures will drop again Wednesday into Thursday, going from around normal to 5 to 20 degrees below normal Thursday.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 548 AM CST Sat Dec 27 2025

Terminals KABR,KATY,KPIR,KMBG

We are starting out VFR, but MVFR fog may briefly move back in at ABR and ATY through 15Z. Expect winds to shift out of the north this afternoon behind a cold front, and increase out of the northwest overnight with gusts of 30-40kts. A 2-4 hour period of light snow will be possible with the strong winds late tonight into Saturday morning, with reductions in visibility with the snow. Expect ceilings to fall to MVFR to IFR after 01Z at MBG/ABR and between 03-06Z Sunday at PIR/ATY. The highest chances of snow overnight into Sunday morning will be at ATY, where there is around a 60% chance of 1" or more snow, and 25% chance of 2" of snow or more.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Dense Fog Advisory until 10 AM CST this morning for SDZ008-021- 023.

Wind Advisory from 9 PM CST /8 PM MST/ this evening to 6 PM CST /5 PM MST/ Sunday for SDZ003-004-009-015-016-033>035-045- 048.

Wind Advisory from midnight tonight to 6 PM CST Sunday for SDZ005-010-017-036-037-051.

MN...Dense Fog Advisory until 10 AM CST this morning for MNZ039-046.