textproduct: Aberdeen

KEY MESSAGES

- A band of light snow moves west to east today. Less than an inch of accumulation is expected with this system.

- Northwest winds Tuesday afternoon into late Tuesday evening could gust in excess of 55 mph.

- Some of the coldest air of this winter season could be settling over the area by the end of the week, including high temperatures around or slightly above 0F and low temperatures down into the single digits below to teens below zero and wind chill values Friday morning as low as -20F to -35F.

UPDATE

Issued at 512 AM CST Sun Dec 7 2025

Aviation discussion below has been updated in accordance with the 12Z TAF issuance.

SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/

Issued at 306 AM CST Sun Dec 7 2025

Only a short break in precipitation is expected as the next round moves in central and north central South Dakota beginning this morning. This precip will be supported by a jet streak aloft, which will traverse eastward through the day this afternoon and evening, bringing the precip with it. Snow is expected to be the main precipitation type through the event, but there is minor potential for a transition to freezing rain this evening. This would occur due to the upper-levels de-saturating, potentially to the point at which temperatures in the saturated layer could be warm enough to support liquid accumulation aloft. Luckily model guidance shows this would be on the very back end of the system as precip is moving out, meaning that the greatest source of lift will be out of the area and precip rates would be lower. With this being such a marginal possibility, no significant freezing rain potential has been added to the gridded forecast, but also would not be surprised to see it if all the variables come together perfectly. Precipitation is expected to exit northeastern South Dakota around midnight tonight at the latest.

In total with this system, only a few hundredths of liquid equivalent are expected, translating to less than an inch of snow across the area. Looking at the latest NBM 90th percentile as a reasonable "worst case" value, QPF values sit around a tenth of an inch. This would translate to between 1"-2" in accumulation. It is worth noting that under a similar pattern yesterday, snow ratios were quite high, so it is possible that we once again will overachieve and come closer to that 90th percentile snowfall.

Monday offers a bit of a reprieve from the snow, and conditions are expected to be dry through the day. Another shortwave supporting a low pressure center will come off the upper-level ridge, but this time it will stay to the north of the Aberdeen CWA. The track of the low will allow temperatures to warm up a bit, particularly over central South Dakota. Highs tomorrow are expected to reach the 40s in that area (about 10 degrees above normal for mid-December), with highs decreasing down to the low-30s as you move into northeastern South Dakota. Areas west of the James River are expected to see highs above freezing, so partial to full melting of the snowpack will likely occur.

LONG TERM /MONDAY EVENING THROUGH SATURDAY/

Issued at 306 AM CST Sun Dec 7 2025

When the period opens Monday night, in the middle of a low level WAA event. Much above normal temperatures are expected to persist into Tuesday, with precipitation developing/working west to east across the CWA, particularly north of U.S. Highway 212. Surface temperatures may be at or below freezing to start Tuesday morning, but within a few hours of sun-rise Tuesday, surface temperatures on an efficient westerly mixing layer wind should be warming things up to above freezing while precipitation potential persists. So, the forecast contains a few hours of freezing rain mention before transitioning to rain potential for the rest of the day.

The clipper system bringing the warm air and precipitation chances on Tuesday will sweep a strong cold frontal passage through the CWA Tuesday afternoon through late Tuesday evening. The combination of already quite strong winds at 0.5km with strong low level CAA and a strong pressure rise/tendency heading into early Tuesday evening supports the potential for headlineable winds. Still too soon to issue a wind headline for Tuesday afternoon/night. But, it is being monitored closely. Not for a blowing snow concern, given all the melting and rain that will have fallen during the day on Tuesday, crusting any remaining snowcover. But, strength of winds may make for rather hazardous traveling conditions. If there is any post cold frontal falling snow to be had across northeast South Dakota Tuesday night, that area could actually see some blowing snow/reduced visibility late Tuesday night into early Wednesday morning.

Still more chances for precipitation showing up, potentially Wednesday night into Thursday morning and again by Saturday. Staring to approach 2 standard deviations below normal for 850hpa standardized temperature anomalies in the ENS S.A. data table for Friday. Ensemble-powered forecast low temperatures Thursday night are below zero (0F to ~ -12F) and high temperatures Friday range from ~ -3F to 12F, with Friday night lows dipping down below zero (~ -2F to -15F) again. Wind chill values are forecast to fall to between -20F to -35F heading into Friday morning while winds are forecast to be 10 to 20 mph sustained with gusts up to 30 mph possible. Simply brutal conditions, that are being monitored for a potential "cold weather" headline.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 512 AM CST Sun Dec 7 2025

Terminals KABR,KATY,KPIR,KMBG

Another round of snow will move into central and north central South Dakota this morning, expanding east through the day today. Snowfall rates are expected to remain fairly low, but will still be enough to reduce visibility at times. Generally MVFR visibilities can be expected where snow is present, with an occasional dip down to IFR visibilities. The same can be said for ceilings, as the main cloud deck will be MVFR with occasional IFR conditions. Snowfall will move out of central/north central South Dakota by this evening and out of northeastern South Dakota tonight. There is some potential for lingering light snow on the back end of the system, so have left a PROB30 group in the TAFs for the ending of the precipitation. MVFR ceilings will also linger on the back end of the system, moving out from west to east near the end of the TAF period Monday morning.

ABR WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None.