textproduct: Aberdeen

KEY MESSAGES

- A Heat Advisory remains in effect into early this evening for Corson, Dewey, Stanley, and Jones counties. Heat indices upwards of 100 degrees will be possible over that area. Temperatures are set to cool down to below normal for Tuesday and Wednesday.

- A Red Flag Warning has been issued for Monday afternoon and evening over portions of central and north central South Dakota due to dry fuels and 20 to 30 mph north winds, including gusts up to 40 mph.

- 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.

- An area of near surface smoke is expected to sweep through the region on Monday behind the cold frontal passage. Concentrations of smoke may be high enough to be able to smell smoke in the air, and reduce visibility down to 3 miles or less. Air quality is expected to drop Monday and Monday night. Those with breathing sensitivities should plan accordingly.

UPDATE

Issued at 953 PM CDT Sun Aug 2 2026

The majority of the forecast for the rest of tonight remains on track, so don't expect the need for any noteworthy changes. Let the Heat Advisory for our West River counties expire on time at 02Z. Temperatures of recovered to cooler ranges and heat indices have fallen as a result.

UPDATE Issued at 629 PM CDT Sun Aug 2 2026

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

DISCUSSION

Issued at 120 PM CDT Sun Aug 2 2026

At 1 PM CDT, skies are mostly sunny (smoke aloft noted on satellite imagery and looking outside), and temperatures are warming into the 80s and 90s. Heat Index values are increasing into the 90s throughout and west of the Missouri River valley. Relative humidity values across that same region are beginning to drop below 30 percent. Winds are out of the south at 15 to 25 mph with gusts up to 35 mph.

Ensembles clusters analysis and deterministic GSM output still saying the positive tilt upper level ridge, bringing the heat today, will be displaced off to the east while Pac NW/western Canada upper level troffing moves east and knocks 500hpa heights down Monday through Wednesday. Rather flat upper level western CONUS ridge/central-eastern CONUS trof looks to set up for Thursday through Sunday, leaving quasi-zonal to muted northwest flow over this CWA. Not a very noteworthy signal for precipitation showing up in the forecast right now beyond any Monday/Monday night precipitation potential.

There is confirmation, upstream, of the HRRR's near-surface smoke progs, per the surface observations reporting reduced visibility out over the northwestern CONUS/southwestern Canada. The HRRR draws this near surface smoke down across the CWA on Monday into Monday night. Incorporating that information (for smoke mention) into the forecast. By Tuesday, air quality should be improving as the area of near surface smoke advects further south and east. Unfortunately, the flow pattern aloft will likely be continuing to steer wildfire smoke, aloft, over this CWA Tuesday and beyond.

Low confidence in getting the max temperatures right on Monday with a cold frontal passage happening, and potentially some morning and late afternoon through late evening thunderstorms. Certainly, warmer (upper 80s to mid 90s) temperatures expected on Monday out ahead of the boundary, and cooler temperatures behind it. Guidance is still showing some widespread windy north-component winds over, at least, the central/north central zones of the CWA, post frontal, on Monday. And, while afternoon RH values may even be a tish higher on Monday than this afternoon, collaboration has yielded a Red Flag Warning across the central/western portions of the Dakotas on Monday.

The cold front moving through on Monday would serve as a low level focusing mechanism for late afternoon/evening convection to develop on, provided mid-level cooling can happen enough to erode mid-level thermal capping. If convection can develop, there is more than adequate dynamic/thermodynamic support for supercellular storms, carrying a large hail/damaging wind threat.

Below normal (lows near 50F! Tuesday night) temperatures are presented in the various ensembles temperature guidance Tuesday and Wednesday before a warm up is set in motion for the rest of the 7- day.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 629 PM CDT Sun Aug 2 2026

Terminals KABR,KATY,KPIR,KMBG

Prevailing VFR conditions can be expected at all terminals through this forecast cycle. Southerly winds will remain gusty tonight into Monday. Low level wind shear (LLWS) will be possible by late this evening and early overnight for KABR/KPIR/KMBG terminals. Patchy wildfire smoke will linger across the area tonight into Monday across central South Dakota and portions of northeast South Dakota.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning from noon CDT /11 AM MDT/ to 9 PM CDT /8 PM MDT/ Monday for SDZ003-015-016-033-034-045. MN...None.