textproduct: Aberdeen

KEY MESSAGES

- High temperatures 5 to 15 degrees below normal expected through the middle of next week. Highs are expected to be in the upper 40s to 50s through that period.

- Widespread rain expected Sunday and Monday. Upwards of 1" of rain is expected east of a line from Eureka to Presho through Monday night. Highest totals, perhaps as much as 1.5"-2", will occur east of the James River Valley.

UPDATE

Issued at 628 AM CDT Sat Apr 25 2026

See below for an aviation forecast discussion for the 12Z TAFs.

DISCUSSION

Issued at 153 AM CDT Sat Apr 25 2026

Rain is ongoing this morning over parts of central and eastern South Dakota. Rain rates have been fairly light this morning, just a few hundredths per hour in the heaviest rainfall. Chances for rain will stick around through this afternoon over central and northeastern South Dakota as well as western Minnesota, before transitioning to just areas east of the James River Valley this evening. Through the overnight period tonight, up to a quarter of an inch will be possible over eastern South Dakota (around and southeast of the Watertown area), with locally higher amounts up to half an inch possible. Rainfall totals decrease moving northeast, with little to no accumulation expected northwest of a line extending from Aberdeen to Gettysburg. A handful of flashes of lightning has been observed via satellite in some of the rain further south in Nebraska early this morning in an area of very marginal (<250 J/kg) MUCAPE. This MUCAPE is generally expected to remain to the south through the day today, but may briefly sneak into the forecast area over eastern South Dakota, producing an embedded rumble of thunder or two. Either way, severe weather is not anticipated today.

The main focus of the forecast remains the precipitation chances Sunday through Monday. An upper-level shortwave will develop a Colorado low, bringing precipitation to the northern plains (on the north side of the low). Northeastern South Dakota into western Minnesota is still expected to see the highest precipitation totals from this system. The GEFS does place the track of the storm a bit further east, with some of the highest precipitation bleeding out of the Aberdeen CWA. However, other ensembles keep the axis of heaviest rainfall totals solidly within the CWA, and have retained a bit more run to run consistency (thereby somewhat increasing confidence in those solutions). As for how much rain will fall, latest ensemble median totals generally continue to show upwards of 1" through Monday night for areas east of the Missouri River (with the latest NBM giving a 50-80% chance to reach 1" over this same area). However, a slight uptick in totals have has been observed over northeastern South Dakota and western Minnesota over the past 24 hours, now with a greater area with medians over 1.5". Still a fair degree of spread, as NBM 25th/75th percentiles continue to show between 0.75"and 1" of difference between the two. The highest uncertainty is located in the north between Aberdeen and Mobridge, and likely has a lot to do with uncertainty in the system track as well as uncertainty in the rainfall totals themselves. A final note on this system is that there will be some chances for winter precipitation during the overnight periods when the near-surface layer drops near to just below freezing. However, impacts from winter precipitation are not expected.

Monday afternoon, as the low pressure center passes to the east, a northerly-low-level jet on the back side is expected to move overhead. That same uncertainty in the low track mentioned in the above paragraph is unsurprisingly also present for where this low- level jet will set up. Generally expecting it to set up over central and north central South Dakota, although if the GEFS is to be believed the main threat area may in fact be along the James River Valley. Regardless of location, expectations are that the low-level jet will reach 40-50 knots at 850mb, and soundings show some chances to mix to the surface. Still, things look marginal at this point to reach Wind Advisory levels, with the latest NBM probabilities under the jet reaching just 20-40%.

Mid-week, ensemble clusters still show confidence in an upper-level trough with the base over the Midwest/Great Lakes region. The cold air aloft allowed into the region by the trough will help to regulate temperatures, keeping the northern plains 5-15 degrees below normal through at least mid-week. This setup is not expected to be very conducive to precipitation, and little is expected at this time beyond Monday night.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 628 AM CDT Sat Apr 25 2026

Terminals KABR,KATY,KPIR,KMBG

Guidance depicts the current VFR conditions at KPIR, KMBG and KABR will persist throughout the TAF valid period. Any lingering rain chances at KPIR/KABR this morning should be ending prior to 18Z today. KATY is in MVFR (cigs) conditions and is expected to remain so for the rest of today. Off and on showers/light rain are expected to continue over KATY during the next 12 hours or so, along with occasional visibility drops down to MVFR (4-5SM). By 03-06Z, the precipitation chances at KATY should be ending, and so should any lingering sub-VFR conditions.

ABR WATCHES/WARNINGS/ADVISORIES

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