textproduct: Aberdeen

KEY MESSAGES

- Fast moving storms this evening/overnight (20-40%). Initially a large hail (up to 2" diameter) threat for north central South Dakota, transitioning to a wind threat (60 to 80 mph gusts) as storms shift east-southeast through the overnight.

- Heightened Fire Weather threat for Monday. Lightning starts from storms tonight are possible. Northwest winds of 25 to 40 mph during the day, with afternoon humidity down to around 20% across central/north central South Dakota, 25-35% across the northeast/western Minnesota.

- Smoke from western wildfires could move into central/north central South Dakota behind the front. Minor impacts to visibility.

UPDATE

Issued at 902 PM CDT Sun Jul 19 2026

Adjusted sky cover grids slightly to better align with current satellite trends. Also let the Heat Advisory expire at 02Z. Watching storms across north central SD this evening, with more activity upstream in ND perhaps set to make their way into northeast SD later tonight. PoPs OK for the time being but may have to make some adjustments to increase in the next couple hours depending on radar trends.

DISCUSSION

Issued at 146 PM CDT Sun Jul 19 2026

Cloud cover has helped suppress temperatures thus far, though humidity has likewise responded higher. Comparing current readings to NBM by 18Z, were about 6-10 degrees too cool from Mobridge to Miller and points east, while central South Dakota is on track. More sun moving into north central South Dakota and eventually the James valley, so will leave headline in place but trended Highway 281 and points east temperatures a few degrees cooler as mid clouds head that direction.

Focus is on severe weather potential later this evening. We are at the southern periphery of a rather stretched, weak wave thats over North Dakota. Flow in the mid levels associated with this feature is increases to 40kts between 00-03Z out of the west northwest. At the surface, we have decent southerly flow, which has picked up the humidity from recent rainfall. Dewpoints across central/north central South Dakota are running about 3-5F higher than what was predicted from the previous run of the NBM so a little richer environment for convection, with the NAM/HRRR at around 2500- 3000j/kg. That said, BUFKIT profiles suggest deep mixing is still required for surface based convection (up to 8kft). There is also a fetch of dry air above 500mb. Aside from the southerlies in the boundary layer, straight line hodographs and about a 40kt storm motion means still looking at a wind threat once storms get organized. CAMS are mostly pointing to development 01-03Z across north central South Dakota, though a few cells may briefly develop in central South Dakota. The north central activity will then rapidly move towards northeastern South Dakota through about midnight, but it should be noted that CAMS are pointing towards more isolated to scattered coverage.

The RAP/HRRR are bringing in smoke behind the frontal system as well, with the Air Quality Forecast Guidance Viewer likewise pointing to smoke migrating northwest to southeast across the Dakotas. Concentrations are significantly lower in comparison to what the east coast has been dealing with. Elevated smoke is also predicted and have adjusted sky cover to match. Unsure of thickness and what impact it will have on mixing which will thus effect temperatures/humidity and winds.

Regardless, NBM temperatures/winds/humidity currently point to Red Flag for north central South Dakota, which mostly missed out on morning precipitation. While Mobridge did get 2" of moisture about 10 days ago, Gettysburg fell shy of an inch and Lowery SDSU mesonet has only picked up 0.17" for the month. Grasses on webcams are getting dry and we've had some fires already across north central South Dakota, and despite rainfall potential (which is really very limited in coverage and amounts) issued a Red Flag for Monday.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 632 PM CDT Sun Jul 19 2026

Terminals KABR,KATY,KPIR,KMBG

Overall, VFR conditions are forecast through much of the TAF period. Will be watching potential for TSRA across the region this evening and have included PROB30 for northern TAF sites to cover this. MVFR/IFR VSBY possible in heavier downpours. Severe storms possible as well, with hail (GR) and surface gusts over 60 knots. Areas of wildfire smoke aloft and potentially at the surface is forecast to overspread the region from the north on Monday.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning from 3 PM CDT /2 PM MDT/ to 9 PM CDT /8 PM MDT/ Monday for SDZ003-004-009-015-016. MN...None.