textproduct: Aberdeen

KEY MESSAGES

- Showers move through the area today and tonight. The probability of 1" of moisture is about 30% across central South Dakota, with about a 30-40% chance for 1/4" for northeast South Dakota. The least amount of moisture is expected across north central South Dakota.

- There is a marginal (1 of 5) and slight risk (2 of 5) in place along and south of Highway 212 from Pierre east. The main threats are high winds (60 to 75 mph) and large hail (around golf-ball sized) in the highlighted area.

- Above normal temperatures (+5 to +10 degrees) continue through the week, peaking at 10 to 20 degrees above normal Friday/Saturday.

DISCUSSION

Issued at 156 AM CDT Tue Sep 1 2026

Negatively tilted trough coming up from the south brings in a plume of moisture from the Intermountain West. BUFKIT profiles are mainly moist adiabatic, with the GEFS/EC PWATS right at about or a little shy of 2 standard deviations above climo. Best forcing is centered around 600mb in an east-west axis that lifts north across the area during the day. After that, a north-south oriented wave embedded within southwest flow aloft provides additional forcing. CAMS highlight this area for stronger convection with this wave. There is an axis of instability but the GFS/NAM both have this axis south of the CWA with limited elevated instability over us (NAM peaks at about 500j/kg MUCAPE). It comes down to the very high shear within this environment. 0-6km shear is about 50kts with REFS paintballs for 2-5km helicity and 10m wind speeds highlighted in the latest SPC risk area. Thus, a high shear low CAPE setup.

In the wake of the system, with high pressure overhead and to the northeast, light northeasterly flow and recent moisture means the potential for fog. CAMS are highlighting the upslope areas of the Sisseton hills.

We remain in a southwest flow regime in the wake of this system. There is another southwest flow wave, albeit much weaker, for Wednesday night. With such a weak system, NBM is only carrying about a 20-40% chance for weather. NAM BUFKIT profiles show skinny CAPE but another favorable shear dynamic across the northeast.

An upper trough over the Pacific Northwest sits and deepens for the rest of the week and into the weekend, building/intensifying the ridge aloft. 700mb temperatures are running at about a standard deviation above climo for the latter half of week and through the weekend. The GFS/EC do bring a backdoor front/cooler low level airmass down into the region early next week.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 636 AM CDT Tue Sep 1 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions for all terminals. KPIR has the greatest chance for seeing storms, slightly less so for KATY and with the lowest probability being KMBG. Winds should be easterly, so once we get some moisture and clear out, there could be some fog for KATY at around 12Z/end of the TAF period.

ABR WATCHES/WARNINGS/ADVISORIES

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