textproduct: Aberdeen

KEY MESSAGES

- Rainfall moves in later this morning, persists through most of the day, moving out late this afternoon. On average moisture expected ranges between 1/2 and 1 inch with locally higher amounts.

- Warmer next week, with temperatures persistently above average. Highs range in the 80s to around 90 (10 to 20 degrees above normal).

DISCUSSION

Issued at 1256 AM CDT Fri May 22 2026

Precipitation out west river to the Missouri valley this morning consists of rain showers with another axis of shower activity coming up from southeast South Dakota/northeast Nebraska. The two areas zip up across south central South Dakota late this morning, associated with the main shortwave, then lift northeast through the day. The coma head precipitation stalls in north central South Dakota through about 22-00Z with the northeast seeing a bit of a dry slot between 18-22Z. This exposes the warm sector/southeast quadrant of the low to daytime heating... but first moisture potential:

Again, moisture with this system will do a number on the spring rainfall deficit. REFS 24 mean and max is upwards of an 1" to 1 and 3/4" respectively. HREF 25th/75th is about 2/3" to +1". NBM 25th- 75th range remains 1/2" to +1". Thus, a good soaker for most of the forecast area.

If 'ifs' and 'buts' were candy and nuts then we could see low topped supercells and tornadoes. There is some skinny low level CAPE and favorable low level shear in the southeast quadrant of the system late in the day. The NAM probably highlights the worst case scenario best, showing a narrow ribbon of 0-1/0-3km CAPE and 0-3km shear of 30kts resulting in a localized sig-tor parameter 1/2 to 1, in an environment with LCLs of only 1500ft coming up through southeast South Dakota terminating up around the Huron area. The RAP is less impressive with these values, while the HRRR/REFS are also hinting at some ingredients coming together. Then again the best ingredients are across southeastern/eastern South Dakota and any concern for our area is stronger cells glancing the CWA.

Still looking at a warm up to above normal temperatures Sunday through most of next week. The upper trough/low that plows into the Pacific Northwest causes a buckle in the jet with initially zonal flow with temperatures jumping into the 5-10 degrees above normal range Sunday. The ridge strengthening Monday/Tuesday and then we get into southerly flow aloft. Low level flow thus becomes southerly, and persistently so for most of next week. 700mb temperatures increase to a standard deviation above climo, which allows for highs to run 10 to 20 degrees above normal. Low level humidity will also be on the increase. NBM increases POPs but not real confident on the upper pattern and progression for the latter half of next week onwards.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1222 AM CDT Fri May 22 2026

Terminals KABR,KATY,KPIR,KMBG

A storm system will bring widespread rainfall, reduction in vsby and cigs later this morning and through most of the valid taf period. The system should push northward late this afternoon, with pcpn ending as well. The terminal of KATY could see thunderstorms between 21-01Z.

ABR WATCHES/WARNINGS/ADVISORIES

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