textproduct: Aberdeen

KEY MESSAGES

- A gradual warming trend is expected over the next three days. Highs increase from the 50s to low 60s this afternoon to the 60s to mid-70s by Wednesday.

- Strong southerly winds gusting to 30-40 mph combined with afternoon humidity of 25-35 percent will create High to Very High grassland fire danger this afternoon across central SD. Fires that start may spread quickly.

- Strong northerly winds return Thursday behind a cold front. Gusts are expected to peak over central South Dakota at 30 to 40 miles per hour. The strong winds will also cause elevated fire weather concerns Thursday afternoon.

DISCUSSION

Issued at 205 AM CDT Mon Mar 23 2026

The broad pattern to start this week comes in the form of an upper- level ridge over the western CONUS, allowing warm air to occupy the Northern Plains. A gradual warming trend is expected through Wednesday as heights gradually rise, going from highs in the 50s and 60s this afternoon to the 60s and 70s on Wednesday.

Pressure gradient will tighten today as the high pressure center exerting influence over the region moves off to the southeast. This tightening leads to a roughly 30-35 knot low-level jet moving overhead, which with a well-mixed boundary layer expected this afternoon, those winds speeds will be seen as gusts at the surface. Combined with central and north central South Dakota seeing minimum afternoon humidity between 25 and 35 percent, there will be elevated fire weather concerns this afternoon, and the Grassland Fire Danger Index reaches the High to Very High category across the forecast area.

There are also some chances for the development of some rain showers this afternoon and evening along that low-level jet. Moisture advection from the southerly jet will provide ample humidity aloft, but a dry layer near the surface may limit the ability of any showers that do develop to reach the surface. Therefore, only a couple of hundredths of accumulation at the most is expected with showers that develop. The latest ensemble guidance giving only a roughly 20% chance of a hundredth of an inch, mainly over northeastern South Dakota and western Minnesota.

As the upper-level ridge flattens out late Wednesday into Thursday, a jet streak aloft will move over the forecast area, developing a low pressure center and leading to the potential for some precipitation development. Model soundings indicate a dry layer near the surface that any rain showers would need to overcome, so it may be difficult to see any accumulation at the surface. Still, the latest ensemble runs place a 0-40% gradient (increasing from south to north) over the Aberdeen CWA for the probability to see a hundredth of an inch of accumulation.

As the low pressure center progresses eastward and drags a cold front across the area Wednesday night, winds behind the front will turn northerly and increase. Current expectations are gusts around 30-40 miles per hour in the afternoon, with the NBM showing pockets of 10-20% chances to hit Wind Advisory criteria of 45 miles per hour. However given the NBM's tendency to under-do post-frontal, northerly wind speeds, those values could easily be an underestimate. These winds will likely cause elevated fire weather concerns Thursday afternoon, although at the moment it appears that humidity will remain high enough (30 to 45 percent at minimum) to keep the area out of Red Flag Warning territory.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1229 AM CDT Mon Mar 23 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through Monday evening. Light winds become south-southeast today with gusts to 25-30 kts.

ABR WATCHES/WARNINGS/ADVISORIES

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