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 632 PM CDT Sat Apr 25 2026

The forecast remains on track this evening. No major changes are planned.

DISCUSSION

Issued at 254 PM CDT Sat Apr 25 2026

High pressure currently resides over the area sitting just north of a surface trough over southern SD into NE/IA with these features residing behind a vertical cold front extending from Canada through MN. We are still seeing an area of stronger 925-850mb fgen, oriented southwest to northeast, over east central through southeastern SD into MN/IA. This has been the focus for banded light elevated rain showers, which are currently ongoing. CAMs indicate this rain will continue through this evening before diminishing. Not much in the way of MUCAPE, therefore, thunderstorms are not anticipated.

Our attention then turns to Sunday as a stronger shortwave will move in and over the Southwest US in the morning where it will track northeast (and become negatively tilted) and over the central/southern Plains by late Sunday/early Monday with its surface Colorado low developing and strengthening. The center of the ~996mb elongated low, and its shortwave, will track over the Central Plains Monday where it will then track northeast and over MN/WI by Monday evening. ENS is a bit further south/southwest with the track of the low than GEFS as it tracks over the Central Plains with Canadian model being the most northerly track. As the low tracks northeastward through IA and into MN/WI by the evening, ENS/GEFS seem to come together better at least on location with still a spread on the strength and width of this low. GEFS continues to have a deeper/wider low (993mb) and stronger wave aloft with ENS more of a smaller and weaker low (995mb).

With this setup, the CWA will be on the northern side of the low (inverted surface trough) with WAA rain moving in over south central mid to late Sunday morning with the rain spreading north and northeastward over the CWA through the afternoon. As this low tracks closer to the region, rain will be widespread (pops of 90-100%) over the CWA and falling pretty steady Sunday evening through early/mid Monday morning as the CWA will then be on the northwest then western side of the low. Rain will end west to east across the CWA Monday afternoon with the last of the precip to exit eastern SD/western MN by late Monday evening.

ENS QPF amounts indicates upward of an inch over east central/southeastern SD into MN while GEFS extends these QPF amounts a bit further west into our CWA and a bit higher amounts. Latest NBM run has shifted a bit eastward with the higher rainfall potential then previous run. Upwards of one inch of rain is possible along and east of a line from Hecla to Miller through Monday night (40-75%), with the highest confidence east of the James River. There is a 15- 20% chance of 2" or more QPF along and east of a line from Sisseton to Huron. However, there is still quite a spread between the 25-75th percentile with a difference of about ~0.3" over central SD, and 0.6 up to an inch over portions of northeastern SD/western MN. This spread is quite high due to the exact track/strength of the low (as mentioned). Still a bit of lower confidence on exact amounts at this time. Super ensemble plume mean for KABR is right under an inch, 1.25" for Watertown, and 1.30" for Sisseton. NAEFS indicates mean specific humidity and PWAT values between 1-2 standard deviation above climo between 12Z Sunday and 00Z Tuesday. PWAT values are on the order of 0.75 to 1" east of the Mo River, highest over eastern SD, which is in the 80-95th percentile. NBM also highlights the potential for some light snow or rain/snow mix over the western portions of Corson/Dewey counties Monday morning as temps will be hovering at or near freezing. No hazardous weather expected.

On the backside of the low, 850mb winds will increase to 30-50kts out of the north. Colder air along with steep low level lapse rates and pressure rises will lead to winds increasing over central SD early Monday with winds increasing over northeastern SD/western MN through the midday/afternoon and continuing over the CWA through Monday evening. Probability of wind gusts>45 mph is 30-50% between the Mo and James River Monday afternoon. NBM max 24hr wind gusts indicate the potential for 50mph gusts. So a Wind Headline may be needed closer to time. Winds will diminish west to east across the CWA as the low continues to track away from the region and high pressure moves in.

By the midweek, the Northern Plains continues in a troughing pattern aloft as this 850mb low/open wave will continue to track over the eastern half of Canada. Split flow forms for the end of week over the western CONUS with a ridge to the north and trough over the south. Models indicate this ridge becomes more positively tilted as it track east but also become less amplified. This will help warm temps back up into the 50s and potentially 60s by the end of week. Precip wise there is possibility of light rain (20-40%) west of the Mo river Tuesday and 20-25% chance over north central Tuesday night per a low/frontal boundary lee of the Rockies.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 632 PM CDT Sat Apr 25 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will deteriorate on Sunday as moderate rain moves in during the afternoon. Cigs will fall to MVFR while vsby drops to MVFR/IFR in heavier showers.

ABR WATCHES/WARNINGS/ADVISORIES

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