textproduct: Aberdeen

KEY MESSAGES

- Some isolated to scattered showers and thunderstorms could develop or move over portions of east central South Dakota and west central Minnesota by early this evening, with rain chances persisting over those areas into the early overnight. There is a marginal risk for severe thunderstorms, mainly in the form of 1 to 2 inch hail potential, this evening into the early overnight hours.

- Warming trend in place through mid-week, with temperatures persistently above average through the end of the 7-day forecast. Highs range in the upper 70s to upper 80s throughout the period. Monday and Tuesday could see highs reaching or exceeding the 90F degree mark (15 to 20 degrees above normal) in some places.

- Isolated to scattered evening and overnight thunderstorm chances (20-40 percent chances) exist off and on by Thursday evening, continuing into Sunday evening.

DISCUSSION

Issued at 204 PM CDT Sun May 24 2026

At 1 PM CDT, skies are sunny and temperatures are warming through the 70s and low 80s. Winds are generally light from the south around 10 mph with some occasional gusts up to 20 mph. MLCAPE has increased across the southeastern forecast zones to around 500-750J/kg, and that is forecast to increase a bit more through 00Z. Deep layer shear is currently around 35 knots, and may hold around that value or perhaps drop off to closer to 30 knots by 00Z this evening.

More potential isolated to scattered showers/storms on the low level jet later this evening and into the early overnight hours, as a decent low level moisture advection feed continues across portions of northeast South Dakota and west central Minnesota. There is also a clearly discernible mid-level shortwave working through eastern Montana that could serve as some extra-added UVV's for storm development on tonight's low level jet over the region. Between the available low level moisture/instability and the anticipated 25-35 knots of deep layer shear around tonight, convection that develops on the low level jet could produce some large hail (1-2in in diameter). Most of the llj focus/forcing is to the south/east of this CWA, but SPC's current SWODY1 does have a small portion of this CWA's southeast forecast zones in a marginal risk for severe (mainly hail threat) weather.

The low level jet eventually points northeast into Minnesota, taking the low level moisture with it. Conditions on Monday will be much drier across the Missouri River valley and James River valley regions, as the next iteration of low level moisture advection that southerly winds will bring to the CWA do not really appear to ramp up, in earnest, until after 4-5pm CDT Monday afternoon, with the best available moisture to generate convection on the nose of Monday night's low level jet not arriving until at or after midnight CDT. Still there could be a storm or two around later Monday night east of the Missouri River valley, mainly along/north of the U.S. Highway 212 corridor.

By the time Tuesday rolls around, the much talked about upper level ridge will be squarely overhead, while a west coast upper level trough is digging in. The potential for mid to late week heat of the day storms still exists, but hinges on just where the western CONUS upper low and central CONUS upper ridge sets up in this potential split flow scenario, as further west positioning makes precipitation chances better for the central/northern high plains and front-range areas versus a further east positioning, which would continue the higher chances for precipitation moreso across the central and northern plains regions (including a portion of this CWA). And split flow scenarios several days out in the forecast typically make forecast confidence in flow pattern details sketchy, at best. Suffice it to say, there are still couple of 24 hour periods out in the extended where the QPF ensemble clusters analysis indicates measurable precipitation possible over the CWA.

There will certainly be a tug-of-war thing going on between the much warmer air this upper ridge will draw into the region and the green- up that is occurring. When it's green and getting greener, the low level moisture in the boundary layer doesn't get mixed out quite so fastly versus when vegetation/trees, etc are brown/dead/dormant and drying out/heating up the boundary layer is an easier thing to do. Will watch and see how warm it gets today, and leverage that information to inform Monday and Tuesday's forecast high temperatures.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1212 PM CDT Sun May 24 2026

Terminals KABR,KATY,KPIR,KMBG

Other than a shower or thunderstorm potentially getting within 40 miles of the KATY terminal this evening, good VFR conditions are forecast through the TAF period.

ABR WATCHES/WARNINGS/ADVISORIES

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