textproduct: Aberdeen

KEY MESSAGES

- Showers and thunderstorms returning starting late tonight, continuing through Sunday, with rain persisting into Monday.

- Slight Risk (2 of 5) mostly focused across northeast South Dakota and west central Minnesota Sunday afternoon/evening. Marginal Risk for severe weather (1 of 5) includes parts of the northeast and central South Dakota. Main threats are large hail and a tornado or two.

- Colder air returns Monday through Wednesday, with high temperatures around 15 to 20 degrees below normal. Temperatures Wednesday morning may drop to near or below freezing.

DISCUSSION

Issued at 253 PM CDT Sat May 16 2026

After today's relatively quiet conditions, an active pattern will begin to set up across the Northern Plains and Upper Midwest late tonight into early next week. Sfc ridging nudging southward from the center of the high in southern Canada has led to another dry day across the forecast area. Winds have been more tolerable today compared to the previous couple days, but they aren't exactly non- existent. Still seeing gusts between 15-25 mph with some locally highest gusts in places like our southwest zones(south central SD) and northeast zones(northeast SD/west central MN). The combination of these winds and low RH values are leading to near critical fire weather conditions on both ends of the CWA. And, if they haven't quite yet, it's expected they will the as the afternoon hours progress. Improvements on both ends are expected by early to mid evening as winds/RH improve across west central MN and RH's recover across central SD.

Attention will then turn to a well organized storm system that's currently taking shape southwest of our region today. As an upper trough axis continues to dig into the Rockies, lee side low formation will take place across the Front Range/Northern High Plains later today into tonight. This system is progged to shift out into NE on Sunday with an inverted trough extending north into western/central SD. This is all expected to gradually track into eastern SD and western MN Sunday afternoon and Sunday night. Guidance still progs a series of shortwave energy rotating northeast into our region over the course of Sunday into Monday. CAM solutions keep us mostly dry in our forecast area until around 06Z. The first wave and associated precip is expected to arrive into central SD early Sunday morning and then track northeastward through the pre- dawn and post sunrise hours. Some of the CAMs are suggesting that this activity may/may not be a solid coverage of showers and thunderstorms as it comes into our western/southwestern zones. At any rate this should track northeast of the CWA by mid-late morning with a possible break in the precip from late morning through early afternoon.

By Sunday afternoon, the air mass become more unstable with time, especially across southeast SD and our far south/east zones. BUFKIT soundings suggest that a good portion of our forecast area may status over during the morning hours leading to more stability while our far south/east zones become more unstable. KATY's forecast sounding shows a period of elevated CAPE during the mid afternoon to early evening hours. This would coincide with SPC's Slight Risk (2 of 5) across east central SD and west central MN. Primary threats still remain large hail with damaging winds, locally heavy rain and and an isolated tornado as secondary threats in those areas. Guidance progs a line of convection forming by late afternoon across those zones before shifting it off into southeast SD/western MN by the early evening hours. There should be another break in the precip from Sunday night into Monday morning before the next upper wave and secondary low pressure system track southeast of our region. This will provide another good opportunity for rainfall Monday afternoon through Monday night. Expect all of this activity will remain general showers and thunderstorms as the main threats for severe weather will be shifted farther east and south of us by that time.

Temperatures do take a decent plunge beginning Monday as that system rain system rotates through the region. Below normal temperatures for both daytime highs and overnight lows are expected through the middle of next week. High temperatures in the 40s and 50s both Monday and Tuesday and overnight lows in the low to mid 30s Monday night into early Tuesday and again Tuesday night into early Wednesday will be possible. If we see those chilly temperatures at night, given the right conditions, there will be areas of frost to contend with across most of the forecast area.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1245 PM CDT Sat May 16 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected to prevail the remainder of today into this evening. North to northeast winds this afternoon will become east to southeast during the latter half of the afternoon at KPIR/KMBG and at KABR/KATY late this evening into the overnight. KPIR/KMBG terminals will see wind gusts this afternoon up to 25 kts and then essentially remain steady or increase further overnight into Sunday morning. The stronger winds will spread east overnight into KABR/KATY and persist through the end of this forecast cycle. Showers and thunderstorm chances will increase from southwest to northeast overnight and persist through the morning hours. MVFR cigs move into KPIR/KMBG around sunrise Sunday morning and spread east into KABR/KATY by mid-late morning. IFR cigs will also be possible late in this TAF valid period.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning until 10 PM CDT /9 PM MDT/ this evening for SDZ033>036-045-048-051. MN...None.