textproduct: Aberdeen

KEY MESSAGES

- A Slight (Level 2 of 5) to Marginal Risk (Level 1 of 5) for severe thunderstorms to develop this afternoon through evening for central South Dakota. Hail of 1 to 2 inches in diameter and wind gusts of 60 to 70 miles per hour will be the main threats.

- A Marginal Risk (Level 1 of 5) for severe thunderstorms to develop Friday afternoon into evening over far eastern SD and west central MN. Hail of 1 inch in diameter will be the main threat.

- A warming trend begins by the end of the week, and highs may 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.

DISCUSSION

Issued at 131 PM CDT Thu Jul 9 2026

A frontal boundary will be moving over western SD this afternoon and then pushing east into central SD during the evening and overnight hours. Instability over central SD will be increasing through the day, with CAPE values looking to get up onto the 1000-2000 J/kg and shear values between 30-35kts. This will make for a good environment for storms to continue to move into and/or develop over central SD during the later afternoon into the evening hours. There is a slight (level 2 of 5) to marginal (level 1 of 5) risk for these storms to become severe. With DCAPE values of 1200-1300 J/kg and lapse rates of 7.5 C/km, the primary hazards are large hail of 1 to 2 inches in diameter and wind gusts of 60-70 mph. Into the overnight hours, the storms will continue to move east into a weaker environment that will likely cause the storms to dissipate before they reach northeastern SD.

Friday morning, the frontal boundary will be moving into northeastern SD. As it moves in during the early morning, some isolated showers and storms could develop in that area as it will have a little bit of instability. Though there will not be a lot of shear for severe storm development. Additionally, weaker lapse rates will reduce the risk for large hail. There could be some gusty winds as well as some small hail that could occur in the storms that pop up. The boundary will not move too much through the day, and with a fair bit of instability building up over northeastern SD through the day, storms could develop during the afternoon into the evening over northeastern SD and west central MN. At the moment, the NAM shows up to 30 kts of shear and lapse rates around 6-7 C/km, which could help with hail development. This leads to the primary threat from the storms to be hail up to 1 inch in diameter, though some stronger wind gusts cannot be ruled out.

An upper-level ridge will be moving high pressure in over SD this weekend. This will help to keep precipitation chances from developing showers and storms over central and northeastern SD Saturday through Monday. The high pressure will also help move warm temperatures, about 10-20 degrees warmer than normal, in during the weekend and into the beginning of next week. Max temperatures and heat index values will be in the 90s on Saturday and in the mid 90s to triple digits Sunday and Monday. We are holding off on an extreme heat watch/warning at the moment because the days with the highest risk are still a few days out and things could still change a bit. Central and northeastern SD and west central MN are right on the edge of extreme heat warning criteria, and might fall more into a heat advisory. Because of the lower confidence in things at the moment, a heat headline will likely need to be issued a little later. The high temperatures and heat index values as well as the warmer low temperatures at night have caused the NWS Heat Risk to show high chances of getting into Major category as well as some lower chances of getting into Extreme category Saturday through Tuesday. During these times, those sensitive to heat or without adequate cooling or hydration could see heat related impacts and/or develop heat illnesses. Make sure to avoid strenuous outdoor work and exercise during the hottest parts of the day and to stay hydrated.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1227 PM CDT Thu Jul 9 2026

Terminals KABR,KATY,KPIR,KMBG

There are VFR conditions this afternoon and into the evening. KABR and KATY will see these conditions continue while some scattered afternoon cumulus clouds sit in the sky this afternoon. KPIR and KMBG could see conditons degrade a little during the evening as thunderstorms are forecast to move into central SD between 22/23z into the evening. There is a slight (level 2 of 5) to marginal (level 1 of 5) for storms to become severe, with hail up to 1 to 2 inches in diameter and wind gusts of 60 to 70 mph. The storms will dissipate overnight back into VFR conditions. KPIR and KMBG could also see wind gusts up to 20kts through the evening before the storms arrive.

ABR WATCHES/WARNINGS/ADVISORIES

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