textproduct: Aberdeen

KEY MESSAGES

- There is an Enhanced Risk (Level 3/5) for severe storms for all of central and northeastern SD into west central MN this afternoon through tonight. Main threats include wind gusts of 75+ mph, large hail (2+ inches in diameter) and tornadoes (EF2+ possible).

- There is a Marginal Risk (Level 1/5) for isolated severe storms Wednesday afternoon and evening along and east of a line from Britton to Brookings. Hail, one inch in diameter, and 60 mph gusts are the main threats, although the strongest convection is most likely to occur east of the Aberdeen forecast area.

- Cooler temperatures arrive for the rest of the week and into the weekend. Highs beginning Thursday will be in the mid 70s, near- normal to just below normal for this time of year.

UPDATE

Issued at 614 PM CDT Tue Jun 9 2026

See below for an aviation forecast discussion for the 00Z TAFs.

DISCUSSION

Issued at 212 PM CDT Tue Jun 9 2026

The main forecast highlight today continues to be the potential for strong to severe thunderstorms developing this afternoon and continuing through this evening and overnight. A negatively tilted trough over the western CONUS develops a low pressure center over North Dakota/southern Canada, leading to a cold front moving across the region this evening, ahead of which storms are expected to develop today. As for storm mode and timing, current expectations are that individual cells will form over western/central South Dakota before coalescing into a line as the storms pass the Missouri River and continue east.

With the initial development and assuming storms remain discrete as they enter the Aberdeen CWA, hail will be a favorable threat. Strong CAPE of 2000-3000 J/kg will be in place with the initial development, and LCL-EL shear of 45+ knots and mid-level lapse rates between 7-8 C/km will also support hail development, potentially upwards of 2" at times. As storms progress east and morph into a QLCS, the primary threat will shift to wind. DCAPE values well over 1000 J/kg will be in place, low-level lapse rates near the dry adiabatic lapse rate will also offer easy access for gusts to mix to the surface. 0-6km mean wind and EBWD both around 30-35 knots further support the wind threat as well. With such a strong environment for severe winds, we may see widespread significant wind gusts (75+ mph) through the evening and into the early overnight period.

As for the tornado threat, there appear to be a couple of things working against the potential at this point, but can't quite rule things out. Currently, the best chances appear to be as the storms coalesce into a line just east of the Missouri River. Hi-res model guidance is pointing towards the idea that achieving 0-3km shear will be somewhat difficult. LCLs out ahead of the front will also be fairly high (>1000m) until around sunset, although there is a bit more of a disagreement withing the models on this specific point. All this to say that generally speaking, variables don't seem to quite line up well for the tornado threat, with the exception of the Campbell/Walworth/McPherson/Edmunds County area. In that spot, shear increases along the front, LCLs come down below 1000m, and low-level helicity of 200-300 m2/s2 will be present. Therefore, wouldn't be surprised to see a spinup in that area in particular. The other possible tornado scenario (albeit one that seems fairly unlikely) is for a discrete supercell to develop out ahead of the front and main line of convection this evening over northeastern South Dakota, where if timed correctly (around 01-02Z) may be able to tap in to some low-level shear. However, guidance gives very low confidence in storms developing out ahead of the front, so there is limited concern for this scenario at this time.

The Storm Prediction Center also has a Marginal Risk for severe weather in place for far northeastern South Dakota and western Minnesota for possible development Wednesday afternoon. At this point there is still quite a degree of variability in location and timing within the CAMs for Wednesday afternoon, but the one consistent point seems to be that the strongest storms will develop to the east of the Aberdeen forecast area, so limited concern for severe development tomorrow.

Upper-level trough is expected to progress eastward through the end of the week this week. The most prominent impact here will be height falls across the region, leading to near-normal to slightly below normal temperatures beginning Thursday. The replacement of the mT airmass with a cP airmass will also push dew points in the 60s today to the upper 40s by Thursday (roughly between the 25th and 50th percentiles for this time of year). By next week model guidance begins to diverge a bit on how the upper-level pattern will evolve, but in general expect cold air advection aloft with some potential for shortwaves to move through and develop some additional rainfall chances.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 614 PM CDT Tue Jun 9 2026

Terminals KABR,KATY,KPIR,KMBG

Not sure if/when storms are going to develop over central South Dakota, but guidance continues to indicate thunderstorm potential at the KMBG and KPIR terminals generally between 01Z and 03Z. Storm mode would be supercellular, with large hail and damaging winds being the primary severe weather threats. An isolated tornado concern is a lower probability secondary severe weather threat. Beyond that, a cold front should be pushing into the Missouri River valley signaling a wind shift and stabilizing conditions and the end of any precipitation potential. Outside of convection, VFR conditions are forecast to prevail through the TAF valid period.

Guidance still indicates convection should develop over western/central South Dakota over the next 2-3 hours and increase in coverage as it moves off to the east-northeast. Once it reaches northeast South Dakota (KABR/KATY), it could be forming into a line of storms capable of rather strong/damaging straight line winds. Presently still leaning on a window between 04Z and 07Z for this convective activity to role through the KABR/KATY terminals. Beyond that, a cold front should be pushing into the James and Big Sioux River valleys later tonight after 06Z, signaling a wind shift and stabilizing conditions and the end of any precipitation potential. Outside of convection, VFR conditions are forecast to prevail through the TAF valid period.

ABR WATCHES/WARNINGS/ADVISORIES

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