textproduct: Aberdeen

KEY MESSAGES

- The first of two upcoming winter systems moves into the forecast area late tonight into early Wednesday morning. Around 4"-7" is expected over north central and parts of northeastern South Dakota as well as western Minnesota. Between 2"-5" is expected for central and parts of northeastern South Dakota. A Winter Weather Advisory is in effect for all counties (except Jones, Lyman, and Buffalo) early Wednesday morning through Thursday.

- The Wednesday and Thursday system will also bring chances for freezing rain to parts of eastern South Dakota, particularly in the Watertown area. While confidence is low, some parts of Deuel and Hamlin counties may see upwards of a tenth of an inch of ice through Thursday.

- Strong easterly winds will gust up to 25 to 35 miles per hour Wednesday, decreasing Thursday to gust up to 20 to 30 miles per hour. The combination of falling snow and strong winds will cause decreased visibility, at times as low as half a mile on Wednesday in particular.

- A second system will move in from the west Thursday night through Saturday bringing potential for freezing rain and additional snow. Impacts to travel are expected. There is a 40 to 70% chance of more than 4 inches of snow northwest of a line from Murdo to Watertown to Ortonville. Freezing rain will be possible Thursday night into Friday morning from Pierre to Watertown.

UPDATE

Issued at 1231 AM CDT Wed Apr 1 2026

The aviation discussion has been updated for the 06Z TAFS.

UPDATE Issued at 610 PM CDT Tue Mar 31 2026

The forecast is still on track this evening as we enter monitor mode for the initial approaching winter system. No major changes are planned at this time.

SHORT TERM /THIS EVENING THROUGH THURSDAY AFTERNOON/

Issued at 243 PM CDT Tue Mar 31 2026

The first of two systems bringing winter precipitation arrives tonight, beginning over central South Dakota. Surface and low-level temperatures are going to play a key role in determining the precipitation type during this event, but expecting mainly snow out of this system overall. There are a couple possible exceptions to snow as the precipitation type during this event. The first comes on the front end, where temperatures at the lowest levels may stay above freezing for the first couple of hours and produce rain over parts of central South Dakota. However, the freezing level is expected to be quite low, and the melting layer may not be deep enough to fully melt the snow before it reaches the surface. This same concept also applies to Wednesday afternoon should high temperatures reach above freezing. This may be a challenge however given the cloud cover present through the day limiting insolation. The second exception comes over parts of northeastern South Dakota (the Watertown area in particular) on Thursday morning. Model soundings indicate a warm nose aloft, and the major question will be whether or not that warm nose will reach above freezing and melt the snow falling through the profile. European ensemble runs trend that warm nose a bit warmer, which is why we see some higher freezing rain accumulation out of it. The GEFS on the other hand trends it a bit colder, but is still hovering right around freezing. All this to say that a subtle warmup in the ~700-800mb layer could be enough for precip type to switch on a dime in future runs. The latest trends indicate the the European model is closer to the right track over parts of eastern South Dakota, and that Deuel and Hamlin counties in particular may see up to two tenths of accumulation in total through Thursday.

In terms of snowfall totals through this first event, the last few NBM runs have consistently shown an upward trend in the median snowfall amounts, as well as a slight shift north with the latest run. The track in particular will be something to watch as the event begins, as there is still some signal for a shift back to the south. Through Thursday, much of the area is expecting between 3"-7" in total, and the latest NBM probabilities of 6" have trended up to 50- 75% over parts of north central and northeastern South Dakota as well as western Minnesota. However, the thought is that these higher end values are less likely to materialize on the ground for a couple of reasons. First, given the past few days having above normal temperatures, most of the ground will be thawed, with current 4" soil temperatures reading above 40 degrees at nearly all locations. Therefore, for at least the onset of the event, there may be some help from the warm ground in preventing snow from sticking until it cools further. Secondly, given the duration of the event, the expectation is that there will be plenty of time for compaction to limit the accumulations. So while upwards of 6" may fall to the ground, confidence is low on actually seeing 6" of accumulation and the associated impacts.

A tightening pressure gradient will bring another element into the equation with this system. Winds out of the east at 20-25 miles per hour will gust up to 25-35 miles per hour, which when combined with the falling snow may reduce visibility at times. Snow ratios are generally expected to be around 10:1 through the event, so being a bit on the wetter side the snow will likely be more difficult to blow around from the surface. In addition, snowfall rates will rarely (if ever) exceed half an inch per hour over the duration of this event. Therefore, not anticipating blizzard conditions at this time, although a close eye will need to be kept on visibility observations through the event. The easterly wind direction will also create favorable conditions for some potential upsloping along the Prairie Coteau. This may lead to some localized higher snowfall amounts may be possible over that area.

As a result of all of these factors, a Winter Weather Advisory has been issued for all counties, with the exceptions of Jones, Lyman, and Buffalo. Timing on this Advisory essentially lines up with the onset and departure of the snowfall. Areas west of Brown and Spink counties have the Advisory run from 1 AM CDT Wednesday through 1 PM CDT Thursday. Areas from Brown and Spink counties and eastward are six hours delayed, beginning at 7 AM CDT Wednesday and continuing through 7 PM CDT Thursday. An upgrade to a Winter Storm Warning is not out of the question alongside later forecast packages, but there are currently no plans to do so at this time.

LONG TERM /THURSDAY EVENING THROUGH TUESDAY/

Issued at 243 PM CDT Tue Mar 31 2026

Primary focus for the long term part of the forecast is the second wave of wintry precipitation for Thursday night into Saturday.

This second wave of precipitation is tied to another upper trough dropping through the western CONUS, phasing with the southern stream jet and developing a low in the lee of the Colorado Rockies on Thursday evening. That low will then track through the KS/MO/NE/IA intersection region Friday afternoon before lifting northeast towards WI by Saturday morning. Will note that the AIFS-Ens MSLP lows does have the track a little farther south and slower than the EC-EPS/GEFS membership, so will be something to monitor with future shifts. While the forecasted track is a little south from where we usually like it for heavy snowfall across our CWA, that appears to be offset somewhat by the track of the 500mb shortwave/low across SD, and the similarly with the 700mb low (while model locations vary, still appears to be in SD). Thus, we should have solid upper level support for widespread precipitation late Thursday night and into Saturday. The primary questions come down to how much QPF and the P-Type. First for QPF, EC-EPS EFI data continues to highlight this second wave with EFI values in the 0.6-0.7 range for Friday into Saturday (slightly lower on Saturday). While the EC-EPS had been a little lower on QPF 24hrs ago, definitely seen a trend up by around 0.1-0.25" for the 24hr period ending 06Z Saturday. So the going forecast has followed that trend with QPF trending upward, which has consistency across all of the ensembles (traditional and AI ones like AIFS-Ens/AIGEFS). Final position will depend on the track of the upper low and moisture/lift on the north/west side of it. This currently looks to be focused across northern and especially north central SD at this point, with 48hr probabilities of 0.5" of QPF over 75% across much of the CWA (decreases to 20-40% chance of 1").

The focus then turns to P-Type for this event. Seeing an increased FZRA potential for Thursday night (starting in central SD) and then shifting east through Friday morning into east-central and northeast SD and into west-central MN. This is tied to a warm air nose between 850-750mb that pivots through while surface temps are expected to be below freezing. EC-EPS is the most aggressive on the freezing rain potential from Pierre to Watertown area, while the GEFS is less impressed on any RA/FZRA potential and only on the leading edge of the precip. NBM P-Type probs have FZRA as the dominate p-type through Fri morning in that Pierre to Watertown area, before the warm nose erodes and snow becomes the focus. Once the p-type switches to snow, should see it remain that way for the rest of the event. SLRs will likely be in the 9-11:1 range for the event, and with the current QPF amounts, our 48hr totals stretch from 4-8", greatest over the northwest half of the CWA. Factoring in 25th-75th percentile values from NBM v5.0, we're looking at 2-4" range for 48hrs over the southeast part of our CWA, while the northwest is 5- 10" range. One item of note for our snowfall amounts is that they do not factor in compaction or any melting from the ground, so they may end up running a little high compared to final numbers. Of course, we also still have a couple days for things to adjust/change too. Finally, would expect us to need at least an advisory at this point, but will hold off on any headlines at this point so we don't have 4 day long product.

Beyond the system, a ridge over the western CONUS will become established again and lead to northwesterly flow aloft over the region. At this point, other than a weak shortwave brushing the northeast part of the area on Sunday night, looks to be dry through the rest of the extended forecast. With the expected snow on the ground, should see temps slowly warming for the middle/end of next week towards more normal values, but that timing will all depend on how quickly the snow we receive melts.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1231 AM CDT Wed Apr 1 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail through the early morning hours at all TAF sites. Chances for light snow will begin to increase at KPIR/KMBG closer to a 10Z-12Z time frame later this morning and then continue in an on/off fashion through the remainder of the morning hours. Some blowing snow will be possible as east winds gust to around 25 kts. Light snow may become more steady during this afternoon into tonight and become mixed with rain at times at KPIR. MVFR/IFR CIGs and VSBYs are expected closer to midday and prevail through the remainder of this forecast period.

Light snow chances spread east into the KABR/KATY areas later in the day, moreso during the afternoon hours and then into tonight through the end of this forecast cycle. Light snow will become mixed with rain by late this afternoon into tonight with MVFR/IFR CIGs and VSBYs becoming more prevalent with time. Easterly winds will also gust to around 25 kts late this morning through the end of this forecast cycle.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Winter Weather Advisory from 7 AM this morning to 7 PM CDT Thursday for SDZ006>008-011-018>023.

Winter Weather Advisory until 1 PM CDT /noon MDT/ Thursday for SDZ003>005-009-010-015>017-033>037.

MN...Winter Weather Advisory from 7 AM this morning to 7 PM CDT Thursday for MNZ039-046.