textproduct: Aberdeen

KEY MESSAGES

- A Cold Weather Advisory is in effect for northeastern SD and west central MN tonight through mid morning Sunday for wind chills of -20 to -35 degrees. Wind chills near these values could cause frostbite on exposed skin in as little as 10 minutes.

- Winds Sunday afternoon will gust of 30 to 40 mph from the Missouri River through the higher elevations of northeastern South Dakota (Prairie Coteau). These winds and recent snow over the past 24 hours will result in low level drifting snow.

UPDATE

Issued at 1018 AM CST Sat Dec 13 2025

Snowfall reports continue to filter in this morning from central SD, with 4" of new snow near Onida, 3.5" near Highmore and 1.5" near Seneca, 2.5" in Pierre, and 3.0" near Hayes. The winter weather advisory has been allowed to expire. Light snow around Pierre and south will continue to diminish in intensity/coverage through the rest of the morning hours. Our attention shifts to the cold weather tonight, and the increased winds out of the south Sunday afternoon.

SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/

Issued at 212 AM CST Sat Dec 13 2025

As of 2am radar indicates a band of light/moderate snow extending from Dewey County southeastward through Hyde County with HREF snowfall rates forecast around a quarter inch per hour through 12Z. KPIR is down to 1SM and KMBG at 4SM. CAMs/HREF overall agree that the last of the snow will exit our southern CWA around 14-15Z with storm total amounts forecast of 1 to around 3 inches. The Winter Weather Advisory remains in effect until 9am CST. Otherwise, the main concern in the short term will be the very cold temperatures expected today and especially tonight.

A 1040mb arctic high pressure system will move in from the northwest through the day and will be directly overhead this evening through the overnight hours. Surface and 925mb winds will be out of the northwest this afternoon with 925mb temps ranging from -16C to -21C with 850mb climo temps in the 5 to 10th percentile, almost 2 standard deviation below climo! With this, HREF indicates highs will only range from around 1 below zero to around 10 degrees above zero, coldest James Valley and eastward, which matches well with the NBM. EC EFI indicates values of -0.8 to -0.9 east of the Missouri River with a shift of tails of zero over eastern SD for MaxT today. Sisseton's record low high today is zero set in 1931 with a forecast high of 1 today, so it will be close! With the high overhead tonight, clearing skies, winds becoming light, and a snowpack, strong radiational cooling will allow temps to tank tonight. Kept the trend of going a bit below guidance as lows are forecast to range in the single digits to teens below zero with the coldest temps James Valley and eastward. It is possible we could see even colder temps over the James Valley as NBM probability of lows at or below -20 is 30-50% from northern Spink through Brown and western Marshall/Day counties. Prob of temps below -25 is less than 25% for this area. Wind chill values will range in the teens to around 30 below zero, again lowest wind chills James Valley and eastward. Due to this, A Cold Weather Advisory goes into effect at 6pm this evening through 16Z Sunday.

Otherwise, quiet weather expected Sunday with the the high continuing to track southeast, with the CWA on the northwest side of it as winds will switch out of the south/southeast. To our west, a surface trough will set up from WY through MT, south of a low over Alberta at 12Z, with this trough sliding a bit eastward through the afternoon. Due to this pressure gradient increase, winds will increase over central SD Sunday morning and spreading eastward over the CWA through the afternoon with speeds between 10-20kts and gust up to 35kts, highest over the Coteau. With these winds and fresh snow from this morning, patchy blowing snow is possible over central SD and portions of northeastern SD through the day. We will see increasing downsloping winds off the Coteau towards the late afternoon into the evening. With patchy blowing snow possible here, this may reduce visibilities at times. With more of a southerly flow, temps will be a bit warmer with highs ranging from the mid teens to the upper 30s, coldest closer to the high over western MN with warmest temps over south central SD. Wind chills James Valley and eastward will still be in the teens below zero still around noon, and warming into the single digits below zero by late afternoon.

LONG TERM /SUNDAY EVENING THROUGH FRIDAY/

Issued at 212 AM CST Sat Dec 13 2025

Sunday night there is a strong inversion developing across the CWA, NAM BUFKIT profiles depicting a temperature at 2500ft of +17C. Meanwhile surface temperature lag with a due south wind. Flow is northwesterly to westerly from top to bottom above the NBL (Unidirectional) for the Summit site. BUFKIT also has 50kts in the critical layer so there will be a period of Sisseton hills downslope Sunday night. NBM captures this to some extent, so will leave this part of the forecast alone as it is at the tail end of some of the CAMS but current forecast may be slightly under-representative of downslope wind potential. Total duration is also only about 6 hours as winds shift from southwest to west. Fun fact is with temperatures near 60 degrees at the top of the inversion, those mixed winds might be quite a bit warmer in comparison to the surrounding area.

Low level flow weakens for Monday with a west northwest component. Temperatures may get fairly close to the freezing mark despite snowpack up in the northeast, so long as we maintain the strength suggested by NBM which is about 5 to 10kts. A 2020mb surface high moves overhead meaning mixing is probably over representative. NBM 25th/75th range for highs is only about 4-5 degrees. For the James valley and points east, the lower bound runs between upper 20 to low 30, to a high end of mid/upper 30s, with the highest range of about 7 degrees over western Minnesota.

Mixing will be better Tuesday with mild air aloft. The mild air more or less remains in place for Wednesday. Early Thursday, a strong frontal passage brings us back to the reality of winter in the Dakotas. The surface low is in southern Canada, so little actual moisture with the system.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1117 AM CST Sat Dec 13 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected over the next 24 hours. The only exception will be PIR, which will temporarily fall to MVFR with light snow lingering into the late morning/early afternoon hours. As the mid clouds clear we are starting to see some indications of the cold air over the MO River resulting in small streamers of river enhanced light snow where there is open water. We'll continue to monitor the situation, but impacts are expected to stay minimal at this time. Winds will increase out of the south Sunday, with gusts of 25-30kts by 15Z over central SD (mainly MBG/PIR/ABR).

ABR WATCHES/WARNINGS/ADVISORIES

SD...Cold Weather Advisory from 6 PM this evening to 10 AM CST Sunday for SDZ006>008-011-018>023.

MN...Cold Weather Advisory from 6 PM this evening to 10 AM CST Sunday for MNZ039-046.