textproduct: Aberdeen

KEY MESSAGES

- Mild temperatures around 20 degrees above normal are expected today with highs generally in the 40s to around 50 degrees and overnight lows in the 30s. Much colder conditions, even colder than normal for mid January, return late in the week.

- A 30-60 percent chance for light rain today across central South Dakota before an increased chance of 45-75 percent of snow possible Thursday and Friday. Accumulations look minimal, but there could be up to an inch (60-80 percent chance) of snow accumulating up on the Prairie Coteau late Thursday into Friday.

- Strong northwest wind gusts of 35 to 45 mph are forecast today, but may be easier to come by later tonight. Even stronger winds may be possible late Thursday through Friday where peak wind gusts may range between 40-55 mph. This combined with any snowfall could lead to reduced visibility and hazardous weather conditions.

UPDATE

Issued at 523 AM CST Tue Jan 13 2026

See below for an aviation forecast discussion for the 12Z TAFs.

SHORT TERM /TODAY THROUGH WEDNESDAY AFTERNOON/

Issued at 329 AM CST Tue Jan 13 2026

At 3 AM CST, under a partly cloudy sky, unseasonably warm temperatures are running in the 30s and 40s. Winds at the surface are west-northwest 10 to 20 mph with gusts to 30 mph or higher. Off the surface, in and above the low level thermal inversion in place, winds are northwest at 30 to 40 knots. It's also tough to ignore the 150+knot upper level jet streak sweeping down across the region on the back of the west coast upper level ridge.

Models/guidance have really backed off on the amount of inversion erosion there could be in this "warm sector" environment over the CWA today during daytime heating/mixing. It does not look all that promising. But, if some of the ridge-tops in the CWA do manage to accomplish enough mixing to tap into these winds off the surface, gusts to 45 mph (the bottom of wind advisory gust criteria) would be a thing. Despite the high-end relative humidity around today, and the potential for measurable rain across central South Dakota, the expected west-northwest winds of 15 to 30 mph with higher gusts will hold the Grassland Fire Danger index in the high to very high category over, at least, the western two-thirds of the CWA today.

Tonight's wind forecast will prove the most challenging, as an arctic cold front attached to a surface low (currently analyzed more than halfway through Manitoba and Ontario) will push south/southwest through the CWA. Strong low level CAA in its wake, along with low to moderate pressure rises (6 to 12 hpa in 6 hours), could make the case for a 3 or 4 hour window of advisory criteria north winds over the CWA later tonight, generally along and east of a line from Leola to Clark. Also, all along and behind this fropa, there could be light rain/snow showers or sprinkles/flurries.

Guidance shows this boundary pretty much stalling out in a north- south orientation over the Missouri River valley late tonight/early Wednesday morning. The combination of low level forcing from the stalled/stationary front and any available mid/upper level lift support could mean additional very light precipitation potential (flurries) extending into Wednesday. High temperatures on Wednesday will also prove challenging as conditions west of this stalled boundary will continue to be mild, like the past couple of days, so highs nosing up into the 40s, especially west river, are certainly possible, while the arctic cold air settling over the eastern CWA on the cold air side of the boundary will likely not get out of the teens to low 20s. Surface high pressure will move through the CWA on Wednesday, which should mean a break in the strong winds.

LONG TERM /WEDNESDAY EVENING THROUGH MONDAY/

Issued at 329 AM CST Tue Jan 13 2026

The main focus in the extended period is the snow and wind combination that is expected late this week. The driver of this system will be a low pressure center supported by an embedded wave riding down the transition area between and upper-legvel ridge to the west and a trough to the east. The low is expected to bring multiple fronts across the forecast area Thursday and Friday, providing lift for precipitation development. Overall liquid equivalent amounts are expected to be fairly minimal, and ensemble 50th percentile values show just upwards of a tenth of an inch possible for the 48 hour period ending at 12Z on Saturday. SLRs will increase through the event, making it a little difficult to make a direct conversion from liquid to snowfall totals, but median values for the same time period show around an inch of snow with some localized areas of 2 inches possible over the Prairie Coteau.

Winds are expected to increase Thursday and Friday as well, thanks to the pressure gradient tightening with the incoming low. At this point, the NBM is fairly confident in Advisory level criteria over most of the forecast area (50-80% for 45 miles per hour) Thursday and Friday, with some slightly broader coverage on Friday. High wind warning criteria being reached is still a bit borderline (pockets of 10-30% chances for 58 miles per hour, mainly located over central and north central South Dakota). However, with the NBM's tendency to under-perform on winds under northwesterly flow regimes, it's hard to rule out consideration of a High Wind Warning at this time.

With both the snow and wind in mind, it becomes fairly clear that anywhere snow is falling will see drastic reductions in visibility Thursday and Friday. A Blizzard Warning is undoubtedly on the table for this event still, but a closer look reveals that the setup actually appears quite favorable for a Snow Squall event. Running through a quick checklist, models indicate that out ahead of the front, there will be strong upward vertical motion in the lowest levels and continuing up through the DGZ as well as bands of strong low-level frontogenesis. These factors are corroborated with 0-3km lapse rates between 5-7 C/km. Strong pressure rises behind the cold front are expected, and negative values of Equivalent Potential Vorticity will be present as well. Perhaps the one drawback is SBCAPE values a bit lower than optimal (only around 30-50 J/kg where optimal environments would prefer upwards of 50 J/kg). However with all of the other stability parameters looking favorable, as long as some SBCAPE is present it will likely be enough to get some convection going. All of this is reflected in the Snow Squall Parameter, reaching values of up to 6, the highest values showing overnight Thursday into Friday. Therefore confidence at this time is decently high in some sort of snow squall event occurring. The main consideration moving forward will then become how widespread falling snow will be. Broader coverage will likely push towards a Blizzard Warning, while a more localized look to the models (not unlike what the NBM is already displaying) will push more towards individual snow squall warnings. The situation will continue to be monitored over the next day or two to attempt to reconcile the best course of action for this event.

The broader pattern of an upper-level ridge over the western CONUS exerting influence is expected to persist through this weekend and into the start of next week. Even so, high temperatures will return to normal to just above normal for mid-January. No further precipitation is anticipated for the remainder of the forecast period.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 523 AM CST Tue Jan 13 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast at KPIR and KMBG until well after 00Z this evening, despite there being a period of light rain chances mainly between 15Z and 21Z. Then, post-cold frontal (MVFR) stratus is expected to move west-southwest into these two terminals and stick around for much of the period between 03Z and 12Z Wednesday. Some flurries or sprinkles may shake out of the stratus, but this is a fairly low probability potential right now.

KABR/KATY won't see the rain chances today, but similar to KPIR/KMBG, these two terminals should be experiencing a post-cold frontal band of MVFR stratus between late this afternoon and late this evening.

At all four terminals the low level wind shear threat is expected to continue between 12Z and 18Z. All four terminals should eventually get into west-northwest winds today, and experience gusts between 25 and 35 knots.

ABR WATCHES/WARNINGS/ADVISORIES

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