341
FXUS63 KABR 140626
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
126 AM CDT Fri Aug 14 2026

.KEY MESSAGES...

- Showers and weak thunderstorms (50-80%) are expected over
  north central SD today with isolated threats (15-30%) over
  portions of northeastern SD this afternoon and evening. No
  severe weather is anticipated, however, heavy rainfall is
  possible at times.

- Additional spotty chances of rain and weak thunderstorms
  (20-40%) will be possible tonight through Saturday morning,
  mainly across central SD.

- Average to slightly below average temperatures expected through
  the weekend.

&&

.DISCUSSION...
Issued at 118 AM CDT Fri Aug 14 2026

As of 1am radar indicates spotty rain showers in association with
weak energy/moisture aloft over portions of south central SD. These
will continue to dissipate as they track east/northeast. Current
temps range in the 60s to around 70 and dewpoints in lower to mid
60s with winds between 5-10mph.

The Northern Plains remains in slight southwest flow aloft with a
ridge overhead that will amplify a bit through the day with weak
embedded shortwave pulses within it. At the surface winds will
continue out of east this morning, switching to more southeasterly
by the midday, as a weak low pressure system tracks over the MT/ND
border by the midday. In tandem, a lee low develops along the
boundary over western/southwestern SD. With this setup, central SD
will be the focus for WAA showers and thunderstorms this morning and
through the day, with the majority of the NBM pops (50-85%) over
north central SD. Another potential area of showers and
thunderstorms will be clipping east central SD (NBM pops of 20-30%)
per another embedded shortwave tracking northeast from NE through IA
this afternoon and evening. Looking at the CAMS, some of these show
some daytime heating induced shower or perhaps weak thunderstorms
across northeastern SD/MN, so went ahead and added in slight chances
to err on the side of caution. Late this evening through the
overnight hours, the center of the low will continue to track
eastward/northeast across ND (perhaps weakening into a trough) before
strengthening again over northeastern ND/Canada by 12Z Saturday and
its cold front extending southward through the James River per HREF.
The low that was over western SD will track eastward as well and
over south central SD by 12Z. Therefore, we will continue with a
chance of showers and thunderstorms mainly across central SD to
portions of northeastern SD/MN through early Saturday morning. So
kept with the NBM which does a good job broadbrushing the pop
chances due to the variability between CAMS as it keeps them more
spotty with differences in location, timing, and intensity of
suggested precip with really any lack of LLJ to sustain them for
very long.

HREF indicates marginal instability as CAPE values of 500-1000j/kg
over the CWA are forecast this afternoon and evening, highest over
south central SD, with values decreasing with sunset and bulk shear
of 30kts. Along with weak lapse rates, severe weather is not
anticipated at this time with just the threat of a weak thunderstorm
or two if can grow vertically enough into the cooler air aloft.
However PWAT values continue to range between 1.3-1.8" so any
stronger rain shower/storm or slow moving could produce heavy
rainfall.

The center of the low will track northeast through Saturday and into
Quebec by the evening with the cold front by then extending from MN,
through southeastern SD into NE by 00Z Sunday. As mentioned, pops
are possible over central SD Saturday morning, however, low confidence
as CAMS do not show much in the way of precip beyond this time,
with much of it south and southeast of the CWA, as we really
lose that moisture aloft as high pressure will filter into the
CWA behind it. This high will keep the region dry Sunday with
flow aloft turning zonal. A slight northwestern component aloft
over the CWA returns early next as a weak ridge develops over
the western CONUS (then flattens out as it tracks a bit east)
with the Northern Plains between this and another low/trough
moving in over the Hudson Bay. Weak embedded shortwaves aloft
interacting with weak surface boundaries along with daytime
heating/instability will bring chances of rain/storms each
evening into the nighttime hours Sunday and Monday. More
widespread pops are possible Tuesday/Tuesday night per stronger
cold front. Low confidence in details as this is several days
out.

With a cooler airmass aloft, high temps will continue to be near to
below average, ranging in the 70s to the lower 80s today through the
weekend. Other than a bit of a warmup Monday, mainly west river,
temps will continue to be on the cooler side at least through the
midweek. Lastly, HRRR indicates smoke aloft will continue today,
with the higher concentrations tracking north and east this
afternoon and evening with little to no concentrations of smoke over
the CWA late tonight through Saturday as winds aloft will be out of
the southwest, as mentioned.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1233 AM CDT Fri Aug 14 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will continue through the early morning hours at
all TAF sites, although KPIR could flirt with MVFR cigs at times
as some showers push across that terminal. Better chance for
more prevalent MVFR cigs will be possible after sunrise by mid
morning at KPIR/KMBG with showers possible at KMBG through
midday. KATY could also potentially see MVFR cigs during the
afternoon into the evening hours.

&&

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

&&

$$

DISCUSSION...MMM
AVIATION...Vipond