textproduct: Aberdeen

KEY MESSAGES

- Moderate to heavy rains will persist through the morning hours before tapering off west to east by midday through the afternoon. Heaviest swath of rainfall still expected from parts of south central SD into east central and southeast SD.

- An active pattern will persist this weekend into early next week with a 40-70 percent chance of rain Sunday into Monday.

- Temperatures will remain below seasonal normals the next several days before returning to near normal readings the latter half of next week.

UPDATE

Issued at 1234 PM CDT Fri Sep 18 2026

Updated the Aviation Discussion below for the issuance of the 18z TAFs.

UPDATE Issued at 1017 AM CDT Fri Sep 18 2026

Rain showers from the system continue to move east this morning into the afternoon, where areas east of the James river could see additional rainfall amounts between 0.4 inch to 0.75 inch by the time these showers leave this afternoon. Though, there could be some lingering scattered showers exiting eastern SD this evening.

Low clouds and misty conditions are occurring over central and northeastern SD in areas where the rain has move out of. These misty conditions will cause some patchy areas of lower visibilities at times through the afternoon and into the evening. These visibilities should stay above a mile.

UPDATE Issued at 609 AM CDT Fri Sep 18 2026

Updated discussion for the 12Z TAFs below

DISCUSSION

Issued at 340 AM CDT Fri Sep 18 2026

Moderate to heavy rains have been spreading northeast across parts of central and northeast SD early this morning as a sfc low pressure system shifts out of the Colorado Front Range into Nebraska. Southwest flow aloft remains present across the region with an embedded shortwave trough tracking northeast across SD/NE per water vapor imagery. The sfc low is expected to shift east across the SD/NE border area through the morning into the afternoon and then on into western IA late this afternoon and evening.

The main focus in the next 12 hours or so will be the ongoing precipitation falling across our forecast area. Model guidance continues to remain in fair agreement in keeping the heaviest bands of rain across parts of south central SD north and east into sections of east central and southeast SD today. Still anticipate a 1-2 inch type rainfall to occur along and east-southeast of a line from the Pierre area toward the Redfield area and then east toward the Watertown area. Lesser amounts, generally around an inch or less, will be found north and west of this line across the ND/SD border area back into the north central portion of SD. Ensemble mean PWAT values of 1.75 inches remain concentrated across those aforementioned areas and points south and east. These higher values remain near the maximum climatological percentiles for this time of year. As the sfc low tracks south of our area today, a tighter pressure gradient develops between it and high pressure across Ontario leading to an east to southeast breeze gusting up over 30 mph at times from north central into northeast SD. With the rain and thick cloud cover in place today, temperatures will remain steady in the upper 50s to mid 60s east. With the rain ending by midday across central SD, afternoon readings will make the mid 60s to low 70s.

The rainfall will come to an end from west to east today. Central SD will see the rain taper off by mid morning. The James Valley region will hold onto the showers longer through about late morning and midday. Any lingering showers this afternoon will likely be confined to our far eastern zones. Drier conditions will take hold tonight and persist through most of Saturday. Cloudy skies will persist however so temperatures are expected to fall short of climatological normals with daytime reading likely remaining in the 60s. The break from the rain will be brief as guidance wants to bring in the next upper level disturbance on southwest flow aloft by the end of the weekend into Monday. Rain chances with this event currently sit at a 40-70 percent chance with the highest probabilities of precip across central and parts of northeast SD. After another weak disturbance brings some showers to to parts of the area around the middle of the week, shortwave ridging is progged to build in the latter half of next week. This should bring our temperature trends back closer in line with late September normals.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1234 PM CDT Fri Sep 18 2026

Terminals KABR,KATY,KPIR,KMBG

There is currently a low cloud stratus deck lingering behind the rain showers from the low pressure system that went through earlier, with some occasional light rain showers at times at KATY and KABR. The lingering stratus deck will also cause misty conditions at times through Saturday morning at all terminals. Ceilings will be fairly low from the lower cloud bases and lower visibilities from the stratus deck. Ceilings will be varying between IFR to LIFR at times over the next few hours. Easterly winds behind the low will start to turn and become more north northeasterly through the night. Wind gusts between 20 to 30 mph this afternoon will be decreasing through the afternoon and evening to be fairly light overnight.

ABR WATCHES/WARNINGS/ADVISORIES

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