569
FXUS63 KABR 221120 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
620 AM CDT Fri May 22 2026

.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).

&&

.UPDATE...
Issued at 614 AM CDT Fri May 22 2026

Updated aviation discussion below.

&&

.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 /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 614 AM CDT Fri May 22 2026

Terminals KABR,KATY,KPIR,KMBG

A storm system crossing the region will bring widespread
rainfall, MVFR and perhaps IFR conditions. Flying conditions may
improve late this evening and through the overnight hours.
However, patchy to areas of fog may develop toward the end of
the valid taf period.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.

&&

$$

UPDATE...SD
DISCUSSION...07
AVIATION...SD