textproduct: Aberdeen

KEY MESSAGES

- A Heat Advisory has been issued today for Corson, Dewey, Stanley, and Jones counties. Heat indices upwards of 100 degrees will be possible over that area this afternoon. Temperatures are set to cool down to below normal for Tuesday and Wednesday.

- Storms may develop along a cold front moving over the area late Monday into early Tuesday. A Marginal Risk (Level 1 of 5) is in place for parts of northeastern and central South Dakota, as well as western Minnesota. A Slight Risk (Level 2 of 5) clips part of far northeastern South Dakota and western Minnesota. With these storms, the main severe threats will be hail of one to two inches in diameter and wind gusts of 60 to 70 miles per hour.

- Above normal temperatures and strong southerly wind gusts will combine to create elevated fire weather concerns over central and north central South Dakota Sunday, when gusts reach as high as 30-40 miles per hour and relative humidity falls below 30 percent. Elevated fire weather concerns return over that area Monday, with gusts of 35-45 miles per hour west of the Missouri River and humidity again below 30 percent.

UPDATE

Issued at 814 AM CDT Sun Aug 2 2026

Continuing with Heat Advisory (NPWABR) and elevated Grassland Fire Danger concerns (SPSABR), west river, today. No changes planned to the forecast; hot and windy this afternoon.

UPDATE Issued at 621 AM CDT Sun Aug 2 2026

Aviation discussion updated below for the 12Z TAFs.

DISCUSSION

Issued at 231 AM CDT Sun Aug 2 2026

Above normal heat will push high temperatures and heat indices upwards of 100 degrees this afternoon. Therefore, a Heat Advisory has been issued for Corson, Dewey, Stanley, and Jones counties. Southerly winds will strengthen today, gusting up to 30 to 40 miles per hour by the afternoon. These strong gusts will mainly be along and west of the James River Valley. When combined with the heat over central and north central South Dakota, fire weather concerns become elevated. The Grassland Fire Danger Index will reach Very High levels west of the Missouri River as a result. Afternoon humidity is expected to fall just shy of the 20 percent or lower criteria for a Red Flag Warning, so opting for a Special Weather Statement to cover the near-critical fire weather threat this afternoon. Only other item of note today is that wildfire smoke from the Pacific Northwest will continue to move over the region today and into at least Monday. Smoke is expected to remain mostly aloft, creating hazy skies. Still, near-surface concentrations could be enough to cause minor visibility reductions as well as drop air quality to Moderate levels, impacting those sensitive to smoke.

An upper-level trough will move over the Northern Plains beginning Monday. As a result, a cold front will move over the region Monday into early Tuesday. Storms may develop along this front, and storms that do form have the potential to be severe. The main obstacle to storm formation will be a mid-level cap in place. This cap is strongest over central South Dakota and becomes weaker moving to the northeast. Therefore, the area with the greatest chances for severe weather will be over northeastern South Dakota and western Minnesota Monday evening. There is still some disagreement amongst the model soundings on just how much of a cap will be over the area, with some showing little to none. Look for this to come into further focus over the next couple of forecast cycles as the event draws nearer. The main severe threats out of storms that form will be hail and wind. On the hail side, CAPE/Shear combo of roughly 1000-2000 J/kg and 40-50 knots at 0-6km respectively will be in place. Mid-level lapse rates of up to 8 C/km will also be in place, so hail will be a potential threat. Decent confidence in the potential wind threat as well due to a fairly strong signal for DCAPE > 1000 J/kg and low- level lapse rates approaching the dry adiabatic lapse rate where the cap has been eroded. At this time, there is a Slight Risk over parts of northeastern South Dakota and western Minnesota as well as

As the cold front passes over north central South Dakota Monday afternoon, winds turn northerly and will increase once again. Gusts as high 35 to 45 miles per hour will be in place Monday afternoon, once again mainly over central and north central South Dakota. The latest NBM guidance gives a roughly 30 to 50 percent chance for gusts to reach above 45 miles per hour Monday afternoon over Corson and Dewey counties, so the potential for a Wind Advisory will be monitored with future forecasts. These strong winds and the continuation of above normal temperatures Monday will once again create elevated fire weather conditions over central and north central South Dakota. The Grassland Fire Danger Index will be at High to Very High levels.

Behind the cold front Tuesday and Wednesday, below normal temperatures will take hold. Highs both of those days will be in the 70s to low 80s across most of the forecast area, which is about 5-10 degrees below early August normals. The upper-level trough will move out of the area by the end of the week, with a broad, weak ridge expected to take hold of the region. This will lead to the likely return of above normal temperatures, particularly over central and north central South Dakota.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 621 AM CDT Sun Aug 2 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period. Gusty southerly surface winds will develop by late morning and persist into the early evening hours, with gusts from 25 to 30+ kts. Low-level wind shear (LLWS) looks to develop overnight across the region and have inserted mention of this where/when appropriate for KABR/KMBG/KPIR.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Heat Advisory until 9 PM CDT /8 PM MDT/ this evening for SDZ003-015-033-045. MN...None.