149
FXUS63 KABR 090524 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1224 AM CDT Sat May 9 2026

.KEY MESSAGES...

- Slight cooldown expected for the weekend, with highs in the
  upper 50s to 60s both days (roughly 5 to 10 degrees below
  normal). Frost development and freezing temperatures will be
  possible overnight both Saturday night and Sunday night.
  Temperatures will warm back up next week, with highs in the
  70s to low 80s, roughly 10 to 15 degrees above normal.

&&

.UPDATE...
Issued at 845 PM CDT Fri May 8 2026

Expired the Red Flag Warning back at the top of the hour. Going
forecast is doing fine. PoPs for precipitation over North
Dakota, heading this way, appear to be timed well enough. Most
of the southern/western fringe radar returns are mostly
virga/sprinkles. It`s the stuff north of I-94 that has been
showing up as light rain in surface obs, thus far. Seeing that
pronounced wind shift/cold frontal boundary positioned,
basically, right along I-94 and continuing to head south toward
this CWA. Winds should stay up overnight, along with plenty of
cloud cover to help keep temperatures from dropping off much
past 40F degrees across the northern tier zones of the CWA.

UPDATE Issued at 616 PM CDT Fri May 8 2026

See below for an aviation forecast discussion for the 00Z TAFs.

&&

.DISCUSSION...
Issued at 217 PM CDT Fri May 8 2026

Dry and windy conditions are occurring this afternoon, with
widespread observations of humidity below 25 percent. When combined
with the winds of 30+ miles per hour this afternoon, areas from
Brown and Spink counties and east are seeing Red Flag Warning
conditions. This is expected to continue for the remainder of this
afternoon before winds die down and humidity begins to recover in
the evening. The Red Flag Warning for that area will continue
through 8 PM CDT. As of ~19Z, humidity observations west of Brown
and Spink counties has remained above 20 percent, the Red Flag
Warning criteria for that area. Keeping a close eye on observations
for the remainder of the afternoon, but at the moment not
anticipating issuing an additional warning this afternoon.

Hi-res model guidance shows a fair degree of agreement on chances
for some rain over northeastern South Dakota and western Minnesota
tonight developing along a weak cold front dropping south into the
area. Generally expecting accumulation to remain below a tenth of an
inch, although some CAMs show a swath of up to two tenths of an inch
that may impact part of the forecast area. Rain is expected to be
done before sunrise Saturday morning.

While not strong, the aforementioned cold front will drop
temperatures slightly for the weekend. Highs in the upper 50s to 60s
expected both Saturday and Sunday, roughly 5 to 10 degrees below
normal. This cooldown will be enough to support frost and freeze
potential overnight both Saturday night and Sunday night (and
corresponding headlines may now be sent out, as the frost/freeze
program for the year has just begun). At the moment, overnight lows
are forecast to be in the 33 to 36 degree range (widespread Saturday
night, mainly the James River Valley and east Sunday night), so not
quite freezing, but cold enough to support a few hours of frost
development. Some localized areas may get down to freezing for a few
hours as well both nights.

An upper-level ridge will move over the northern plains early next
week. This will allow warmer air to move overhead, and 850mb
temperatures increase to the low double digits Celsius (roughly the
75th percentile for this time of year). As a result, expecting highs
in the 70s to low 80s next week, roughly 10 to 15 degrees above mid-
May normals.

A shortwave embedded into the upper-level ridge will move overhead,
bringing a jet streak along with it. The latest model runs have
become much more consistent with the location of the jet streak, so
confidence has increased on at least part of the Aberdeen forecast
area seeing some shower development due to the divergence aloft.
Thunderstorm development does appear possible given model soundings
and a plume of MUCAPE extending up into the region. Latest guidance
has trended timing of the jet streak to be after midnight, meaning
that with the diurnal surface inversion in place any thunderstorms
will likely be elevated. Therefore, while a severe storm can`t quite
be ruled out, wind will have a difficult time reaching the surface,
and confidence is low on enough instability aloft to create the
necessary updraft for severe hail (although severe hail is a better
bet than severe wind if you had to pick between the two). All this
to say that thunderstorms that develop will likely be sub-severe
with this system.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1224 AM CDT Sat May 9 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through Saturday.

&&

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

&&

$$

UPDATE...10
DISCUSSION...BC
AVIATION...20