textproduct: Aberdeen

KEY MESSAGES

- There is a Marginal risk (level 1 out of 5) for severe storms over central and northeastern SD and west central MN tonight. The primary hazards will be 1 inch in diameter hail and 60 mph wind gusts.

- There is a Marginal risk (level 1 out of 5) for severe storms over portions of north central SD and northeast SD into west central MN Sunday afternoon into the evening hours. Main hazards will be 1 inch diameter hail and 60 mph wind gusts.

- Hot temperatures for September persist into Monday. Highs in the low 80s over northeastern SD to upper 90s over central SD are expected for the next couple of days. Higher humidity values over central SD this afternoon will lead to heat index values in some places getting to the century mark.

- Northwest wind 15 to 30 mph, low relative humidity, and dry cured fuels may result in fire weather headlines on Tuesday.

UPDATE

Issued at 818 PM CDT Sat Sep 5 2026

Severe convection that had developed during the latter half of the afternoon across parts of central and north central SD has diminished significantly in intensity and areal coverage this evening. A couple of lingering showers and a few rumbles of thunder will be possible across parts of central SD during the next couple of hours. Made adjustments to PoPs earlier this afternoon and this evening to account for all this. Refreshed Sky grids to account for current satellite trends as well. We still anticipate some early morning convection to develop across our eastern forecast zones that could persist through the daytime hours Sunday morning.

UPDATE Issued at 641 PM CDT Sat Sep 5 2026

The aviation discussion has been updated for the 00Z TAFS.

DISCUSSION

Issued at 132 PM CDT Sat Sep 5 2026

At 1 PM CDT, skies are sunny and temperatures range from around 80 degrees along the Minnesota/South Dakota border to the low 90s out across and west of the Missouri River valley. Winds have a southeast component to them, 10 to 25 mph with occasional gusts up to 30-35 mph. Heat index values are in the low to mid 90s across central and north central South Dakota.

An omega-block pattern (trough/ridge/trof) is in place over Canada and the United States. This pattern will persist through the weekend before the pattern flattens out for the middle of the week. It's not real clear how the pattern will look by the end of next week, as ensembles clusters analysis appears to imply a rex-block may be setting up along/just off of the west coast, with this CWA possibly in west or northwest flow coming off that block pattern.

For the next couple of days, short-range ensembles/hi-res CAMS, supplemented by GSM output, suggest a potentially active weather pattern of thunderstorms over or moving into this CWA at times. SPC has the CWA in a marginal risk for severe thunderstorms today, Sunday and Monday.

There could be a couple of storms to monitor later this afternoon/early this evening (mainly west river), as preliminary storms are expected to develop on/near the Black Hills and start heading west/northwest toward Stanley/Dewey/Corson counties. Daytime heating is beginning to destabilize the BL and the shortwave energy over Wyoming is making its way over toward this region. Meso- analysis shows instability working toward ~2000-3500J/kg CAPE and deep layer shear of ~20-35 knots. Still thinking mainly multi- cellular storms with wind/hail the main threats with any late afternoon/early evening convection. At this point, any convection reaching the far western/northwestern zones is not expected to last long or develop into an organized system. Additional convection may develop later tonight on a low level jet, currently progged to set up across northeast South Dakota, eastern North Dakota and the northern half of Minnesota. Wherever the best low to mid-level WAA and moisture advection happens whenever the low level jet sets up is where/when convection is expected to ramp up (sometime generally between 07Z and 13Z and somewhere inside a box formed between Jamestown ND, Wadena MN, Willmar MN and Redfield SD). So, lots of uncertainty surrounding tonight's/Sunday morning's convective potential. Mid-level shortwave energy moving up through the intermountain west should add some synoptic-scale lift for storm development overnight as well.

Monday's weather potential could be occurring at a non-traditional timeframe, if the shortwave energy being advertised to lift out onto the northern plains does so in the morning. Could be facing a line of storms, supported by a much stronger (forced) dynamic set-up, entering the western forecast zones sometime between 7 AM CDT and 11 AM CDT Monday morning. Timing is the biggest question right now.

Underneath this upper level ridge, the above normal warmth continues. When the pattern changes next week, the first of a series of cold fronts will pass through the region Monday/Monday night. That will signal an airmass change. Slightly cooler but notably drier air will be over the region on Tuesday. Breezy to windy northwest winds of 15 to 30 mph are expected on Tuesday. Combined with already dry/dormant fine fuels and low relative humidity, a portion of the CWA could end up in a fire weather headline on Tuesday.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 641 PM CDT Sat Sep 5 2026

Terminals KABR,KATY,KPIR,KMBG

Anticipate generally VFR conditions to prevail at all terminals through this TAF cycle. There will be exceptions to this with shower and thunderstorm activity expected, especially at the KABR/KATY/KMBG aerodromes. Prob30 groups have been maintained for these terminals that indicate the best timing windows for the showers and storms. KATY will have the best opportunity to see MVFR cigs during the morning hours around or after 12Z.

ABR WATCHES/WARNINGS/ADVISORIES

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