Watertown, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

631
FXUS63 KABR 060509 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1209 AM CDT Sat Sep 6 2025

.KEY MESSAGES...

- Temperatures remain around 10 to 15 degrees below normal tonight
  through Sunday.

- Patchy frost will be possible Saturday morning over portions of
  central and northeast South Dakota, and Sunday morning over a
  larger portion of the forecast area as low temperatures fall
  into the mid to upper 30s.

&&

.UPDATE...
Issued at 744 PM CDT Fri Sep 5 2025

Expanded the Frost Advisory across central SD with mostly clear
skies later tonight and light winds allowing temps to fall into
the mid/upper 30s. Otherwise, chilly night all-around and cannot
rule out patchy frost further east across portions of northeast
SD, but there are some questions to cloud cover and wind speeds
staying up just enough to where temps may stay more in the upper
30s. Although, the James River valley could see patchy frost where
winds will be lighter than surrounding areas.

&&

.DISCUSSION...
Issued at 205 PM CDT Fri Sep 5 2025

Much of the morning to early afternoon hours have been showery over
portions of eastern South Dakota, mainly east of the James River.
Additional showers moved in from ND across portions of north central
SD by late morning. The loss of daytime heating will diminish the
coverage and strength of these showers. The stacked surface-500mb
low near James Bay Canada will continue to rotate shortwave energy
through our area early this afternoon, tonight, and again over our
far eastern areas Saturday afternoon. Clouds will be the main result.

At 19Z the surface weather map showed high pressure over much of
KS, but a ridge extending across western SD, eastern MT, and
Saskatchewan. A large exiting low was set up near James Bay
Canada. This was keeping gusty northwest to northerly winds over
our forecast area, with gusts 30-35mph.

Winds out of the northwest to west will slowly diminish to around 10
mph or less by 06Z Saturday. The below normal temperatures continue.
Expect lows near 40 degrees tonight, with a few locations getting
into the mid to upper 30s (mainly over north central SD - closer to
the surface ridge and lighter winds). Patchy frost remains possible
over portions of central SD, with the main focus being western
Corson County - away from the Missouri River. A Frost Advisory has
been issued for Corson County.

The surface ridge slowly shifts over central and eastern SD/west
central MN by Saturday afternoon. A ridge of high pressure over
western South Dakota will slowly edge across central and eastern
South Dakota Saturday afternoon. Any shower development will be less
than today, and farther east. Winds Saturday will be out of the
north to northwest 10 to 15 mph. Fire weather wise, central SD
continues we`ll be monitoring to slowly dry out fuel wise. Relative
humidity values Saturday afternoon will be in the 30% range over
Jones County. 40-50% minimum relative humidity values will be common
over much of the rest of the area, especially east of the Missouri
River. Lighter winds and the potential for 1-4F degrees lower Sunday
morning may result in frost/freeze headlines being needed.

The ridge of high pressure will exit across Iowa on Sunday, with
winds increasing out of the south. The strongest winds of 15 to 20
mph, with gusts of 25 to 30 mph, will be across central South Dakota
Sunday afternoon.

Dry weather looks to remain in place tonight through at least
Tuesday night. The 500mb ridge over eastern WA/OR and ID looks to
finally move over the Northern Plains by 12Z Wednesday. There is
plenty of uncertainty, with about 1/2 of the model guidance
indicating more high amplitude ridging with the other half showing
more flattening of the ridge. We`ll keep the 10-25% chances of
precipitation that are currently in the forecast late Wednesday
through Friday, knowing that this forecast will change.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1208 AM CDT Sat Sep 6 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Frost Advisory until 9 AM CDT /8 AM MDT/ this morning for SDZ003-
     004-009-015-016-033>035-045-048.

MN...None.
&&

$$

UPDATE...TMT
DISCUSSION...06
AVIATION...20