949
FXUS63 KABR 101706 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1206 PM CDT Fri Oct 10 2025

.KEY MESSAGES...

- Light rain this weekend, mainly for the James River Valley and
eastward. Probability of rainfall of a half of an inch or more
ranges from 30 to 50 percent for this area, highest along and east
of the Sisseton Hills.

- Winds will increase out of the southeast Saturday with gusts of 30
to 40 mph through Sunday before diminishing Sunday night.

&&

.UPDATE...
Issued at 1203 PM CDT Fri Oct 10 2025

Aviation discussion below has been updated in accordance with the
18Z TAF issuance.

UPDATE Issued at 1012 AM CDT Fri Oct 10 2025

Forecast on track this morning as high pressure center continues
to build over the forecast area. As a result, clear skies and
winds below 10 miles per hour are still the expectation today. Low
pressure will begin to develop today, and as the pressure gradient
begins to tighten, stronger southerly winds will begin to move in
overnight tonight, fully taking hold of the forecast area by
Saturday afternoon.

UPDATE Issued at 546 AM CDT Fri Oct 10 2025

Updated for 12Z Aviation Discussion below.

&&

.SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...
Issued at 253 AM CDT Fri Oct 10 2025

As of 3 AM CDT, winds are out of the north at around 10 mph.
Temperatures are in the upper 40s to low 50s across the area with
clear skies.

Friday morning, we have an upper level ridge in place with the axis
just to our west over eastern MT. This will move east through the
day and by Saturday evening we are on the upwind side with south
to southwesterly flow all the way down to the surface bringing
some WAA to the region. This WAA will bring a chance of showers
late Friday into early Saturday morning and will continue into the
day Saturday ahead of a cold front. The NBM is showing the chance
of more than a quarter inch as around 10% for the 24 hour period
ending Saturday evening. Temperatures through the short term will
be just slightly above average with highs in the mid to upper 60s.
Model soundings are showing some potential for wind gusts of
30-40 mph Saturday late morning into the evening hours. How high
we will gust will depend on cloud cover and mixing height.

&&

.LONG TERM /SATURDAY EVENING THROUGH THURSDAY/...
Issued at 253 AM CDT Fri Oct 10 2025

Primary focus of the long term will be the upper trough and
associated surface low lifting northeast through western ND on
Sunday. This will bring both the opportunity for rain over eastern
SD (associated with a shortwave and persistent warm air advection
ahead of the low) and then gusty west-northwest winds behind the
cold front that moves through during the daytime hours on Sunday.

First for the precip, expect continued opportunities for rain
Saturday night into Sunday ahead of the cold front and driven both
by the previously mentioned shortwave and warm air advection. These
northeast moving showers don`t look to be overly strong, but could
see some areas accumulate over a quarter of an inch due to the
multiple rounds. 24hr probs of 0.25/0.5in of rain ending Sunday at
7pm continue to be the highest over northeast SD and into west
central MN (50-70% and 30-50% respectively). Some thunder is
possible with the showers, as lifting around 850mb does lead to a
few hundred of J/kg of skinny CAPE. There is 30-40kts of effective
shear in that layer too, which may be part of why some of the ML
severe probs are highlighting very low end chances of severe for the
Sunday period.

Well above normal temps are expected on Sunday ahead of the cold
front as southerly flow pushes 925mb temps up into the lower 20s C
(or around or just above the 90th percentile). Expect the warmest
temps over eastern SD and into west central MN, but the strong
inversion in place will likely keep temps from getting too high, but
also keep the winds in check with gusts in the 25-35mph range.

Once the cold front moves through, will see a lot better mixing due
to the strong cold air advection and the question is how strong the
winds will get. EC-Ens EFI data has been highlighting the stronger
winds on Sunday for a few days now (values of 0.5-0.7), but the
better area still looks to be in northwest SD and western ND, where
they are closer to the low and have the better isallobaric
component. Will need to watch for the potential for a period of
advisory level winds for Sunday afternoon into evening, especially
over central SD.

Behind the system, temps cool to slightly below normal values for
Monday, as a Canadian high pressure ridge slides over the area. This
colder air will bring the potential for frost/freeze conditions on
Sunday/Monday nights. The two questions will be if the winds
decouple enough on Sunday night to allow for temps to fall enough
and lead to frost (doesn`t seem too likely, but temps may still get
around freezing) and then the timing of mid-high clouds to move over
on Monday night (as the surface high departs and southeasterly flow
increases). Otherwise, no significant impacts for next week as
temperatures moderate back toward normal or slightly above normal
values and there are occasional chances for rain.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1203 PM CDT Fri Oct 10 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected today and through the overnight hours as
a high pressure center builds into the area. The main aviation
concern comes at the end of the period, in which a low-level jet of
40-50 knots moves overhead. Gusty winds near the surface will begin
to increase tonight, before peaking Saturday morning and afternoon.
Gusts near the surface may reach up to 35 knots by the end of the
TAF period. This low-level jet will also produce some low-level wind
shear over central South Dakota overnight, and has been indicated in
the KPIR and KMBG TAFs at this time. The jet may also support some
light rain showers, but rainfall rates are expected to be low.
Still, the heaviest showers could drop ceilings to MVFR status, and
both the chance for showers and the drop in ceilings has been put
into a PROB30 group where appropriate. Thunder is not out of the
question, but confidence is very low, and any rumbles of thunder
that do emerge will be isolated.

&&

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

$$

UPDATE...BC
SHORT TERM...13
LONG TERM...SRF
AVIATION...BC