textproduct: Aberdeen

KEY MESSAGES

- Snowfall coming to an end this evening, with any additional accumulations generally around 2 inches or less, mainly in grassy areas. Wet roadways may re-freeze overnight and become slick by morning.

- There is a 50 to 70 percent chance of light rain and snow Friday into early Saturday. Probability of liquid amounts at or over 0.10" is 45-65%, highest over south central through portions of northeastern South Dakota.

UPDATE

Issued at 1223 AM CDT Thu Apr 3 2025

See updated aviation discussion below.

UPDATE Issued at 949 PM CDT Wed Apr 2 2025

Visibilities in falling snow remain under 2 miles from the James Valley east. Snow is also beginning to stick to some road surfaces again according to webcam images. Therefore, since conditions are not improving, decided to extend winter weather headlines again, ending at 6z.

UPDATE Issued at 648 PM CDT Wed Apr 2 2025

Given the ongoing snow and increasing northwest winds, decided to extend winter weather headlines through 03Z from the James Valley east. To the west, snow should continue to taper off with no significant impacts. Across the east, visibilities down to 1 mile are expected with additional accumulations of around an inch that may start sticking on roads again after sunset. Wet roads may also refreeze after dark.

SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/

Issued at 307 PM CDT Wed Apr 2 2025

Surface analysis shows the surface low pressure located over southwest MN, with light to occasional moderate snow continuing to wrap around across the CWA. Additional accums will be minor (~2" or less) for most areas, but higher elevations in the Glacial Lakes region could see those amounts closer to 2 inches. Also, any additional accumulations will likely be confined to grassy areas where temps are around 32-34 degrees. Any areas below freezing could see minor road accumulations. Made several adjustments to headlines earlier today, and will let current headlines run until the current expiration time of 00Z for the time being. Evening shift may be able to start chopping off counties a bit early. Concerning temps overnight, with a lack of any strong cold air advection, plus expected cloud cover, do not foresee temperatures dropping off much more past the mid/upper 20s for most areas even with the fresh snow cover on the ground.

Broad surface high pressure builds over the region on Thursday. Looking at light winds for the day, with cool temps remaining in place, thanks in large part to the snow cover. The Glacial Lakes region will likely be stuck in the mid/upper 30s, while areas across central SD with less snow cover will see highs in the 40s and maybe even close to 50 degrees over areas with little to no snow cover.

Focus will then shift to the next approaching storm system late Thursday night. Inherited NBM PoPs seemed a bit slow in bringing in precip after comparing to the latest 12Z deterministic model runs. Generally did more of an ECAM approach to PoPs from 06Z to 12Z Friday.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 307 PM CDT Wed Apr 2 2025

Split flow aloft starts out the long term on Friday with a deep trough that extends southward into Mexico and a weaker trough extending south/southwestward over the northern CONUS/Canadian border Friday through Saturday. With the northern wave, its weak surface low/cold front will pass northwest to southeast over the CWA. With southwesterly flow aloft to 850mb, models indicate the convergence of moisture from both of these systems over the area Friday. There is still a bit of a difference in timing of this merger as ENS/GEPS has it happening early Friday morning and GEFS more towards the afternoon. Latest NBM has pops of 40-70% over the CWA with the highest percent over central SD. Pops will shift east and southeast with the front through Friday evening with the system moving out of the area by early Saturday morning. Ptype looks to be rain on the warm side of the system and snow or a rain/snow mix over north central SD. However, parts of this area through portions of northeastern SD may see a bit of freezing rain/drizzle early on, as ENS soundings do show a slight warm nose with ENS meteograms hinting at 10% or less of freezing precip. As temps cool towards the evening, ptype will switch over to snow over the area. NBM 24hr probability of QPF>0.10", ending Saturday 12Z, is 45-65%, highest over south central SD. Probability of 1" of snow is 30-40% over north central SD for same time period. High pressure moves in behind the system Saturday with a dry cold front sweeping down from the north late Saturday through early Sunday, associated with a shortwave plunging southward behind the low over eastern Canada. Behind this front, another high sinks southward and becomes dominant for early next week.

Highs for Friday and Saturday will range in the upper 30s and 40s. A ridge to our west will start to bring in warmer air over central SD with highs in this area reaching the 50s for Sunday. As this ridge shifts east, by midweek we could be looking at highs back in the 60s!

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1223 AM CDT Thu Apr 3 2025

Terminals KABR,KATY,KPIR,KMBG

MVFR/IFR conditions will persist through Thursday at KABR and KATY with some occasional breaks to low VFR. MVFR cigs at KMBG and KPIR could improve as early as morning or as late as 20Z. Leaned toward a consensus of hi-res models in the TAFs showing an earlier solution.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Winter Storm Warning until 1 AM CDT early this morning for SDZ006>008-011-019>023.

Winter Weather Advisory until 1 AM CDT early this morning for SDZ018.

MN...Winter Storm Warning until 1 AM CDT early this morning for MNZ039-046.