Watertown South Dakota Weather Forecast Discussion

935
FXUS63 KABR 111126 AAA
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
626 AM CDT Sat Oct 11 2025
.KEY MESSAGES...
- Light rain this weekend, mainly for the James River Valley and
eastward on Sunday. Probability of rainfall of a half of an inch or
more ranges from 40 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 expected through Sunday before diminishing Sunday night.
Strongest gusts are expected along and west of the Missouri River
both days.
- Temperatures will fall into the low to mid 30s on Monday morning
east of the Jame River. This may lead to frost formation and north
central South Dakota has a 50% chance of experiencing freezing
temperatures.
&&
.UPDATE...
Issued at 625 AM CDT Sat Oct 11 2025
Updated for 12Z Aviation Discussion Below
&&
.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 242 AM CDT Sat Oct 11 2025
As of 2 AM CDT, temperatures are in the upper 40s to upper 50s with
some isolated areas a little cooler. Winds are out of the southeast
between 10 and 15 mph. Some showers are expected to move into south
central SD in the next few hours.
This morning the ridge has moved east and we are on the backside
with wind out of the southwest. We stay in southwesterly flow aloft
until an upper level trough moves in with its corresponding cold
front late Sunday and moves winds around the the west. Ahead of
that low and cold front we have some strong winds due to a LLJ.
While we will see some gusts of 30-40 mph, we will most likely not
reach our full potential due to a lack of mixing depth. Model
soundings for today show mixing up to somewhere between 900 and
875 mb but the strongest winds look to reside generally above 850
mb. The NBM is showing chances for gusts higher than 40 mph today
at around 40-60%. Sunday, winds look to be a little stronger
behind that cold front, mainly west river with chances for 40 mph
between 50 and 70%. Along with the winds we will continue to have
a chance for some light rain showers. NBM is showing the chance of
more than a quarter of an inch in 24 hours (ending Sunday
evening) to be around 45-70%, and the chance of more than a half
an inch in the same 24 hours to be around 40-50, highest chances
in far northeast SD and west central MN. Temperatures for this
weekend are expected to be above average, about 5-10 degrees above
average on Saturday, and closer to 10-15 degrees above average
across northeast SD and west central MN on Sunday. Highs are
expected to be slightly cooler for central SD on Sunday as the
cold front moves through. Did bump up highs just a little from NBM
as it seems to be running a little low. With the winds, fire
danger will be locally elevated but won`t reach warning criteria
as RH values will be too high with the showers moving through.
&&
.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 242 AM CDT Sat Oct 11 2025
Weather impacts will be pretty limited during the long term
forecast, with main impacts being tied to the first 6-18 hours of
the forecast (through Monday morning).
As the short term discussion highlighted, will have gusty west-
northwest winds ongoing at the start of the forecast behind the
cold front that moves through during the afternoon. With the
trajectory of the low and the incoming high pressure ridge, expect
gusts of 30- 45 mph over the entire CWA for the first few hours
of the evening under the continued cold air advection behind the
front. Have seen a slight uptick in the winds aloft over the north
central part of SD, so think it`s possible to have some gusts
over advisory criteria for a few hours in the evening. Then as the
high pressure ridge builds over the area through the night
(stretching in from eastern MT and into western SD), the winds
will steadily come down through the overnight hours.
That brings another potential weather impact for Monday morning,
frost/freeze potential. The cold air behind the front will lead to
temps falling into the 30s and potentially even below freezing over
central SD. How cold temps drop will largely depend on how quickly
winds die off, which also impacts actual frost potential too.
Current NBM probs have a 50% or greater probability of temps
reaching 35 degrees or lower along and northwest of a line from KABR-
KPIR, with values over 90% over the north central part of the state.
But when looking at the probs of 32 or colder, they fall to 40-60%
chance over the north central. Latest forecast does show winds
decreasing enough towards day break to include frost in the forecast
for Monday morning, so may need at least a frost advisory issued
during the Sunday shifts. Monday night into Tuesday morning is
another possibility (60-80% chance of temps below 37), but seems
like there are other factors pointing towards it not being a
favorable frost night. That includes the high pressure ridge
starting to depart the area, increasing mid-high clouds ahead of the
next upper trough, and even the potential for some rain (20% chance
over southern SD on Monday night, but over the area on Tuesday
morning).
The rest of the forecast will see temperatures rebounding towards
more normal values on Wednesday as an upper ridge axis crosses the
area. Then the area will under southwesterly flow aloft through the
rest of the work week, as a larger upper trough covers the western
CONUS. As that upper trough shifts east through the end of the week,
expect rain to occur at times, but accumulations are expected to be
on the lighter side (48hr probs of 0.25in for the end of the week
are 30-50%).
&&
.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 625 AM CDT Sat Oct 11 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions are forecast through the TAF valid period. Strong
southerly winds of 25 to 35 kts will develop over KPIR/KMBG and
spread east to KABR/KATY through the afternoon. As a result, low
level wind shear is expected this morning over north central SD
(KMBG) and then again tonight including KABR/KATY. Some light rain
expected over KATY this afternoon and then this evening over all
sites. Did also at a mention of thunder at KMBG with the showers
moving through around the start of the TAF. To low of confidence
on them holding together to KABR to include at this time.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...SRF
SHORT TERM...13
LONG TERM...SRF
AVIATION...13/SRF

NWS ABR Office Area Forecast Discussion