textproduct: Aberdeen

KEY MESSAGES

- Slightly warmer than normal temperatures stick around through midweek with the potential for temperatures to be 15 to 20 degrees above normal by the end of the work week. - Dry conditions continue through Thursday with rain chances (30- 50%) potentially returning Friday night into Saturday. Low confidence in exact track and of the system along with estimated rainfall amounts at this time.

DISCUSSION

Issued at 1257 PM CDT Mon Oct 19 2026

Quiet conditions continue across the region with current temps in the lower to mid 60s and winds out of the east/southeast. The high pressure system that was over the region earlier this morning has tracked east/northeast with the center of the high over the Great Lakes Region and southern Ontario. Through tonight the region sits between this high to our east and an area of low pressure to our west as winds at the surface become more southeasterly late tonight with locations east of the Rockies under a broad upper level ridge per cutoff closed low over the northern Pacific which will track south/southeast and near the southern CA coast by Wednesday morning.

A weak shortwave will traverse eastward across Canada Tuesday and Wednesday with a secondary low developing along the front over western SD Tuesday and tracking across SD on the front before weakening. With this ongoing dry air mass, no precipitation is expected with this fropa passage as it tracks west to east across the CWA with the only indicator is winds will switch from the south/southeast to the north/northeast Wednesday morning and turning more easterly by Wednesday evening as a high continues to track along the northern CONUS/Canada border. A ridge then amplifies aloft over the central CONUS Wednesday evening and Thursday with surface/850mb winds switching out of the south really bringing in the WAA and a bit of low level moisture as dewpoints are forecast to rise back into the 50s through Friday ahead of the low within the warm sector. With diurnal heating and mixing, highs are forecast to range in the 70s to potentially the lower 80s, warmest over south central SD both Thursday and Friday. We may be flirting with record warm highs Friday morning per stronger WAA winds at 850mb to sfc. Probability of temps>80 per NBM is 30-50% Thursday afternoon and 40- 65% Friday over south central SD which leads to higher confidence on the warmer day being Friday as much of the region will be south of the warm front by peak heating. However, NBM 25-75th spread is about 3-5 degrees Thursday and 5-7 degrees on Friday so there could still be some wiggle room on temps as we are still a few days away.

Clusters agree on this cutoff low moving onshore over the southern CA coast ~late Wednesday night/early Thursday morning and becoming a negative tilted open wave with a shortwave moving in over western Canada. The northern wave will track east and the southern wave northeast and somewhat phasing together over the western CONUS Friday with the entire trough continuing its track northeast. Otherwise as mentioned, its low will develop and deepen (~1000mb)over the northern Rockies Friday and track northeast into Canada as the fropa tracks across the region with the CWA behind the system by Saturday evening. This will bring the return of precipitation, in the form of rain, starting with spotty chances (15- 25%) Friday (mainly over northeastern SD/MN associated with the warm front, with the bulk of the precip (NBM 30-50%) ahead and along the front as it tracks east/northeast across the CWA through Saturday morning. Not too much in the form of QPF with a probability of 24hr QPF>0.10" ending 00Z Sunday per NBM is 20-45% along and east of a line from Pierre to Aberdeen highest across east SD into MN. This is fairly close to what the grand ensemble (GEFS/ENS/GEPS) is forecasting. Low confidence in exact track and of the system along with estimated rainfall amounts at this time.

Thursday and Friday will also be windy too as pressure gradients steepen across the region combining with gustier winds aloft behind the exiting high and low pressure to our west with gusts between 30- 40 mph across central SD Thursday afternoon and 30-45 mph Friday afternoon. Probability of wind gusts>45 mph is up to 45-55% over portions of the southern CWA and along the James Valley. With gusty winds and warm temps the end of the week will lead to elevated fire weather concerns across central SD Thursday and the entire CWA Friday even as forecast min RH will stay above 40%.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1212 PM CDT Mon Oct 19 2026

Terminals KABR,KATY,KPIR,KMBG

Dry conditions and VFR cigs are forecast at all terminals through the TAF forecast. Winds continue out of the east/southeast across central SD and easterly James Valley and eastward. Winds will then switch to more of a southeasterly flow then southerly through Tuesday afternoon.

ABR WATCHES/WARNINGS/ADVISORIES

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