textproduct: Aberdeen

KEY MESSAGES

- Patchy to areas of fog will continue through the mid/late morning mainly James Valley and eastward.

- Scattered showers and weak thunderstorms will be possible through the afternoon mainly over portions of south central through northeastern SD and west central MN ahead and along a cold front. No severe weather is anticipated, however, heavy rainfall is possible.

- Average to slightly below average temperatures expected through the weekend.

DISCUSSION

Issued at 148 AM CDT Sat Aug 15 2026

As of 1am, a storm cluster consisting of moderate rain and a few lightning strikes are tracking eastward along/ahead of the frontal boundary over north central SD and into ND where forcing is better, however, CAPE and lapse rates are pretty weak with decent bulk shear between 30-40kts. None of the CAMs really have a good handle, either not showing this storm at all or should be dissipating by now. So if it holds together it will continue to skirt along the ND/SD border bringing the potential for lighting and brief heavy downpours. Areas of light rain/drizzle per WAA flow continues over far northeastern SD into western MN as well. 00Z ABR sounding indicated a nearly saturated sounding, especially at the lower levels, per southeasterly flow near the surface and southwesterly flow between 700-500mb. This is causing fog/low stratus over portions of northeastern SD/western MN per latest obs and webcams showing a reduction in visibility and MVFR/IFR cigs. So have fog mention in the grids through the mid morning.

Within this southwest flow, weak embedded shortwave energy continues to track across the Northern Plains with a more notable shortwave to the south of the CWA in Nebraska tracking east/northeast. An inverted trough/weak low is currently over central ND with its frontal boundary extending into central SD and its weak low lying along the boundary. By 12Z, the low is forecast to over northeastern ND/MN with the cold front extending through northeastern SD into NE, with only a slight movement northeast of the low and east with the cold front. Models indicate scattered chances of showers and thunderstorms here and there ahead and along this boundary, mainly over south central through northeastern SD/MN where better forcing resides, however, differences in timing and location do vary between the CAMs so stuck mostly to the NBM which keeps it more broadbrushed. CAPE values this afternoon will be around 1000 j/kg or less and shear under 30kts, therefore, any storms that occur will be short lived and below severe limits as lapse rates remain weak. However, monsoonal moisture being pulled in per southwest flow is causing PWAT values of 1.7 to almost 2", west to east across the CWA, so any rain shower and/or weak thunderstorms (especially slow moving) could produce heavy rainfall.

By this evening, the region will be behind the cold front, in northwest flow at the surface and winds switching to zonal aloft. A high pressure system will track into the region from the northwest and center itself over the Dakotas Sunday keeping the area dry. This high will shift a bit east Sunday night with pops returning over central SD (40-65%) Sunday night into Monday morning. As the high exits the region, a stronger shortwave and its west to east oriented cold front will drop out of Canada and over the region bringing our best chance for moisture with widespread pops of 50-70%. Still a few days out to nail down specifics or whether severe weather will be a threat.

Temperatures remain around average to slightly below average through the weekend, ranging in the 70s to around 80. Little bit warmer on Monday with highs in the upper 70s to the upper 80s before cooling back into the 70s behind the cold front and incoming high Tuesday and Wednesday.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1233 AM CDT Sat Aug 15 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected to prevail at KPIR/KMBG terminals through most of this forecast cycle. Rain shower activity will be possible through the early morning across central SD. Farther east, KABR/KATY terminals will be dealing with low clouds, patchy/areas of fog and rain showers. MVFR/IFR CIGs and VSBYs will be possible through the morning hours at these terminals before improving conditions expected by mid-late morning at KABR and during the afternoon at KATY.

ABR WATCHES/WARNINGS/ADVISORIES

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