textproduct: Aberdeen

KEY MESSAGES

- Patchy to dense fog will remain possible through this evening. Dense fog and temperatures below freezing could create pockets of freezing fog with icy roads, mainly this morning.

- Above normal temperatures will continue through the daytime hours Saturday, before falling mainly into the teens to single digits above zero Sunday morning through Monday evening.

- A prolonged period of winds out of the northwest will gust around 40 to 50 mph late Saturday evening through the day Sunday.

DISCUSSION

Issued at 413 AM CST Fri Dec 26 2025

Patchy to dense fog will remain possible through this evening. Dense fog and temperatures below freezing could create pockets of freezing fog with icy roads this morning. The light rain that fell from from the passing surface trough is also adding to the icy sidewalks and roadways.

The abundant low level moisture with patchy to dense fog remains a concern, and will continue to be a concern into Saturday. Winds will remain light today, with the surface currently ridge stretching from northern Alberta and central Saskatchewan through central ND shifting along the ND/SD/MN border by 18Z and across MN/IA this afternoon. Winds will increase out of the south over central SD this afternoon, helping to mix/erode the the thicker fog and shift it north. The mention of freezing fog will continue from north central to northeastern SD, especially near the ND/SD border into Saturday as temperatures remain at or below freezing. High temperatures today will be the 30s, except into the 40s west of the Missouri River and over south central South Dakota. Temperatures will stay mainly in the 30s tonight, and rise into the upper 30s and 40s Saturday afternoon. Normal high temperatures his time of year are in the 20s, and in the low 30s south of Pierre. The surface low over MT into southwestern SD will move over western and central SD by daybreak Saturday.

The end to our above normal temperatures will come Saturday night, as a cold front sinks southeast across the area, bringing colder and breezy conditions. Temperatures will be mainly in the teens to single digits above zero Sunday morning through Monday evening.

Behind the cold front, winds out of the north will shift out of the northwest. Gusts of 40 to 50 mph will be possible late Saturday evening through the day Sunday. The 50 mph values are near the NBM 90th percentile for this event, and highest over central SD. Fire weather concerns return to the dry/snow-free areas of mainly central SD. We are forecasting high grassland fire danger index values Saturday afternoon over Jones County, where winds out of the west gust to around 20 mph and relative humidity values fall to around 45 percent. High to Very High grassland fire danger index values are then possible Sunday afternoon over all of central South Dakota. This is where relative humidity values will fall to 40 to 60 percent, and winds will be in that 40-50 mph range gust wise. While we do have around a 20 percent chance of light snow Saturday night into Sunday morning, mainly dry weather is expected to continue. Any precipitation will diminish fire weather concerns.

Wind chill values bottom out Sunday night into Monday morning around -10 to -20F. At this point it doesn't look like any cold weather headlines will be needed for this system, as wind chills stay above the -25 to -30F advisory levels.

Temperatures look to moderate back to near to above normal briefly Tuesday, with highs mainly in the 30s to low 40s (highest over south central SD). Variability increases significantly as we move into Wednesday/Day 5 and beyond. Looking at the ensemble guidance, the GEPS is near the low end temperature-wise, with the GEFS at the high end, with the ENS in between the two. We'll continue to monitor the trends over the next few days, but expect changes to the forecast for Wednesday and beyond. Fro example, at 12Z Wednesday the difference for Aberdeen is -15F to +6F for temperatures.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1127 PM CST Thu Dec 25 2025

Terminals KABR,KATY,KPIR,KMBG

While there may be temporary VFR conditions (either CIGS/VSBY or both) for KABR/KMBG/KPIR and later KATY, these are expected to be short lived with fog and stratus moving back into the area overnight and persisting through morning. Improving conditions are expected Friday afternoon.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Dense Fog Advisory until 10 AM CST this morning for SDZ005>008- 010-011-018>023.

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