textproduct: Aberdeen

KEY MESSAGES

- A dangerous and prolonged heat wave will continue today through much of next week with near record to record temperatures expected and heat index values warming into the triple digits each afternoon.

- An Extreme Heat Warning for north central SD and a Heat Advisory for parts of central and northeast SD and west central MN remain in effect through Tuesday.

- The combination of humidity dropping below 20%, wind gusts of 20- 35 mph, and drying fuels may lead to elevated fire danger concerns over the western portions of Corson and Dewey Counties this afternoon. Elevated fire danger concerns are possible again Monday afternoon along and west of the Missouri River.

UPDATE

Issued at 626 AM CDT Sun Jul 12 2026

The aviation discussion has been updated for the 12Z TAFS.

DISCUSSION

Issued at 100 AM CDT Sun Jul 12 2026

A dangerous and prolonged heat wave is the main concern in the forecast as high temps will range in the 90s to the lower 100s today through next Friday, hottest across central SD. The entire central CONUS is under an impressive highly amplitude ridge that stretches well into northern Canada. Just to give an idea on how anomalous this is, heights run between 596-599 dam over the Northern Plains through Tuesday night which runs in the 99-100th percentile per climo for 500mb heights for this time of year. NAEFs indicates this is about 2 to almost 3 standard deviation above climo. Under this ridge the 500mb high that has been over the Southwest will stretch northeastward and expand over the entire central CONUS (and even eastward) through the middle of next week. By the end of next week, not much change in the ridge aloft (heights a tad lower) with the ridge actually retrograding westward by the weekend. With the region under the heat dome aka subsidence occurring, no precip is expected at least through the end of next week, worsening drought conditions for some locations that have not received rain in the past week or so, especially over portions of north central SD. As what the previous shift mentioned, high pressure at the surface will not be directly overhead and more off to our southeast Sunday through Tuesday and another one forming to our north/northwest over central Canada midweek.

With southerly flow under the ridge, 700-850mb temps also will run 2 to 3 standard deviation above climo per NAEFS today through all of next week. Our hottest days will be today-Wednesday where 700mb temps are forecast to range from +13 to +16C and 850mb temps +25 to +30C during these days with the warmest temps over north central SD. This runs in the 95-100th percentile range per climo at these heights (GEFS/GEPS/ENS). This results in maxTs widespread in the mid 90s to the lower 100s this afternoon through Friday with potential highs reaching up to 106 over north central SD today-Wednesday. However, NBM 5.0 vs 5.2 do vary a bit in MaxT due to the ongoing warm bias of the Canadian model in the 5.0 version with a spread of 1 to 3 degree across the CWA. For example, NBM 5.0 has a high of 98 today at KABR and 5.2 has a high of 96. This seems to be the case as well through much of next week where a 1-3 degree spread remains. So a bit lower confidence on how warm our maxTs will get each afternoon across the CWA. The 25-75th spread becomes quite high for the end of next week, on the order of 8 to 10+ degrees due to lower confidence on the exact intensity and position of the ridge aloft. For example, 25th percentile is 92 degrees and 75th is 106 degrees for KABR. Not much relief overnight as lows will range in the 70s with our warmest nights being tonight/Monday morning and Monday night/Tuesday morning. As for record temps Mobridge will be within 1 degree of record high today through Tuesday. Also Mobridge and Sisseton are forecast to be above for record high mins for Monday morning and MBG again Tuesday morning. Dewpoints will range in the mid to upper 50s to the upper 60s/70s, muggiest over eastern SD/western MN. Luckily where the highest dewpoints are, are offset from where the hottest temps will be, therefore, heat indices will be near actual temps so still quite hot, between 100-105. The Excessive Heat Warning for north central SD and the Head Advisory for central and portions of northeastern SD/western MN continue through Tuesday evening due to heat indices above 100 each afternoon. This will most likely be extended further out in time. As of now, Clark, Codington, Hamlin, Deuel do not reach the 100 degree apparent temp threshold for a headline as of now.

Winds will also remain breezy under the heat dome with overall gusts between 20-35 mph this afternoon and again Monday afternoon. Again as mentioned NBM 5.0 is several knots higher than 5.2 so a bit lower confidence again on max winds. This combining with relative humidity dropping to 25% or less along and west of the Mo River this afternoon (under 20% over north central SD) and west of the James River Monday afternoon may lead to elevated fire danger concerns. Looking at Geocolor from earlier today, Corson, Dewey, and northern portions of Stanley County are dry as areas east of the Mo are quite green due to the previous rains, so lower humidity and gustier winds in this area are ok for now. With the criteria borderline and collab with other offices, went ahead and issued an SPS for Corson/Dewey Counties for this afternoon and will wait and monitor the trends for a potential headline for Monday.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 626 AM CDT Sun Jul 12 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will continue at all TAF sites through this forecast period. Southerly winds will become gusty between 20-30 kts by late morning and persist through tonight.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Heat Advisory until 7 PM CDT /6 PM MDT/ Tuesday for SDZ005>008- 010-011-017-018-021-033>037-045-048-051. Extreme Heat Warning until 7 PM CDT /6 PM MDT/ Tuesday for SDZ003-004-009-015-016. MN...Heat Advisory until 7 PM CDT Tuesday for MNZ039-046.