textproduct: Aberdeen

KEY MESSAGES

- A Marginal Risk (Level 1 of 5) for severe thunderstorms has been posted for parts of northeast SD and west central MN this afternoon into this evening. Hail of 1 inch in diameter will be the main threat.

- A warming trend begins this weekend. High temperatures could potentially hit triple digits Sunday through Tuesday. This level of heat may cause widespread heat related impacts particularly for those without adequate cooling and those sensitive to heat.

UPDATE

Issued at 607 AM CDT Fri Jul 10 2026

Updated discussion for the 12Z TAFs below.

DISCUSSION

Issued at 316 AM CDT Fri Jul 10 2026

Late evening and early morning convection that rolled out of ND into northeast SD and west central MN has mostly diminished below a severe threat concern with only light to moderate rain showers with some embedded thunder left. This activity is expected to continue tracking southeast and continue to diminish in areal coverage through the early-mid morning hours.

Water vapor imagery and upper air analysis early this morning depict broad quasi-zonal flow across the CONUS with two distinct differences from west to east. Across the Great Lakes and Eastern CONUS, some troughiness does exist where a nearly stalled out frontal boundary is leading to showers and thunderstorms through the Ohio Valley into the Mid-Atlantic. Across the western CONUS and Intermountain West, upper flow is beginning to show some shortwave ridging with shortwave troughing working on the downstream side of this ridging across the Northern and Central Plains and part of the forcing for our early morning convection. Through the course of today and into the upcoming weekend, the western CONUS ridging will become more pronounced as it centers itself over the Four Corners region. 500mb heights are progged to increase across our region which should lead to a drier trend as the storm track shifts out of our area. The building upper ridge will also bring is some of the warmest temperatures of the season so far to our forecast area.

For today, a sfc frontal boundary will remain draped in a west to east fashion across our northern zones or in the vicinity of the ND/SD border. This will be tied in with a lee side low located across eastern MT/WY and the Black Hills region. Southerly low level flow on the warm side of this front will maintain a moisture rich air mass with dew point temperatures warming into the mid 60s to near 70 degrees the James Valley and points east into western MN. Daytime heating will push afternoon highs into the upper 80s to mid 90s across the CWA. This will lead to moderate instability of 2500- 3500 J/kg of CAPE across parts of northeast SD and west central MN this afternoon into this evening. However, deep layer shear isn't all the impressive with magnitudes only up to about 25 kts across our eastern zones. Mid-level lapse rates will range between 6-7 C/km in those zones. So, despite increasing mid level heights, CAMs are indicating convective signatures developing late this afternoon into this evening. The early morning convection the moved through northeast SD/west central MN may play into when/where the afternoon activity initiates. Based on the guidance, the most probable areas would be across our east, mainly along and east of the I-29 corridor. The primary threat will be large hail from the strongest cells that develop. SPC has continued to highlight parts of northeast SD and west central MN with a Marginal Risk (Level 1 of 5) for severe thunderstorms this afternoon into this evening.

Storms are expected to be on the downward trend and exiting the forecast area by late tonight. That aforementioned frontal boundary is progged to lift north and through the forecast area on Saturday. Increasing low level southerly flow will keep humid conditions in place through the weekend and the upper ridge asserts itself even more across the Northern Plains. This building heat dome is expected to deliver daytime temperatures that will range between 10-20 degrees above normal for mid July. 850mb temperatures are progged to range from +21C to +25C across our eastern zones to +26C to +31C across our west by the end of the weekend into early next week. Daytime highs on Saturday look to be solidly in the 90s across the CWA with parts of central SD approaching 100 degrees. Sunday through Tuesday will feature even warmer conditions with widespread mid to upper 90s east to the low 100s from the James Valley and points west through central SD. Overnight lows won't provide much relief with readings in the upper 60s to mid 70s. This will mean that daytime dew point temperatures will range from the upper 50s to low 60s west to the mid 60s to near 70 degrees in the east starting Saturday through at least Monday. Heat indices start to creep up on Saturday with mid to upper 90s with a couple of isolated spots approaching 100. This does help to push the HeatRisk probabilities of reaching Level 3 or Major category around 50 percent or higher basically along and north of US Highway 12. So, this will be something we will have to watch the trends closely on for a possible heat headline on Saturday. After Saturday, confidence increases for more widespread heat building across the forecast area. Heat indices are projected to reach 100-105 degrees on Sunday and Monday with HeatRisk values reaching the Major to Extreme category both those days and possibly on Tuesday as well. Future forecast packages will definitely have to consider posting headlines for this extreme heat in the next day or so. Temperatures do look like they will take a step back down by the middle to latter half of next week, but there remains a 10-15 degree spread in the NBM 25th to 75th percentile Max and Min T values which still results in at or above normal temperatures for this time of year.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 607 AM CDT Fri Jul 10 2026

Terminals KABR,KATY,KPIR,KMBG

VFR cigs are forecast through the end of the TAF period. An isolated shower or thunderstorm is possible late this afternoon and evening that could affect the KATY terminal, however, due to low confidence in areal coverage did not put it in the TAF for now. Amendments will be made if needed.

ABR WATCHES/WARNINGS/ADVISORIES

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