Watertown, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

915
FXUS63 KABR 290118 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
818 PM CDT Sun Jun 28 2026

.KEY MESSAGES...

- There is a Slight (2 of 5) to Marginal Risk (1 of 5) for
  severe weather mainly tonight across the central/north
  central SD portion of the forecast area. Severe storms will be
  possible tonight into Monday morning. Main hazards are large
  hail up to 2 inches in diameter and wind gusts of 60 mph.

- Western U.S. wildfire smoke (aloft) will be over the region
  through Tuesday; potentially longer depending on how steering
  flow winds evolve this week. Some minor concentrations of near
  surface smoke could happen from Monday afternoon through
  Monday night.

- There is a Slight (2 of 5) for severe weather on Monday mainly
  across north central SD. There is a Marginal Risk (1 of 5) for
  severe weather Monday evening across the far eastern edge of
  the forecast area. Main hazards are large hail up to 2 inch in
  diameter and wind gusts of 60 mph.

- Temperatures are expected to warm into the 90s, with dewpoints
  in the 70s, across far northeast South Dakota and west
  central Minnesota on Monday. The net result is heat index
  temperatures running up into the 100F to 105F degree range for
  several hours Monday afternoon. A Heat Advisory has been
  issued to address this concern.

- Above normal temperatures are expected to persist for most of
  this week. With highs in the upper 80s to mid 90s and
  dewpoints well into the 60s, and even 70s for some locations,
  especially from Wednesday onward, heat-related illnesses
  become a concern.

&&

.UPDATE...
Issued at 801 PM CDT Sun Jun 28 2026

Quiet conditions across the CWA for now as any spotty rain
showers over far NESD is continuing to diminish as we get
closer to sunset. A pair of splitting supercells lies to our
north near Bismark and south over northern NE. Storms are still
expected to fire up over south central/central SD later on this
evening and track northeast per another jet streak/shortwave
energy rounding the closed low over MT/Canada and to the north
and northwest of a low that will track northward into SD out of
Colorado during the overnight hours. With the help of MUCAPE of
1000-2000 j/k, bulk shear of 50-70kts, and overall elongated
hodographs. Elevated supercells (splitting supercells) will be
the main threat with perhaps a few clusters as well. With the
elevated nature and steep mid level lapse rates, large hail of
2+" is possible along with wind gusts in excess of 60 mph.
Especially if we get gravity wave associated convection, then
wind gusts could exceed 80+mph. For example, the latest HRRR
has a cluster of cells moving in or developing over Jones County
after midnight and quickly tracking northeast, potentially over
Pierre during the overnight hours. Other then minor grid
updates, the forecast remains on track.

UPDATE Issued at 619 PM CDT Sun Jun 28 2026

Updated discussion for the 00Z TAFs below.

&&

.DISCUSSION...
Issued at 127 PM CDT Sun Jun 28 2026

At 1 PM CDT, skies are mostly sunny, with some smoke aloft noted on
geo-color GOES satellite imagery. Temperatures were warming through
the 70s into the low 80s on a south-southeast wind around 5 to 15
mph with occasional gusts to 25 mph.

The table is set for late night convection, initially, across
portions of western/central South Dakota where a synoptic scale
frontal boundary resides. Upper level energy lifting northeastward
into the region will be bringing some higher end mid-level WAA into
the CWA between 06Z and 15Z, about the same time it`s surface low
reflection is working up along the frontal boundary/lee-of-the-
Rockies surface trof. All this is expected to be occurring basically
near/under a 90-110kt upper level jet streak extending from
northwest North Dakota back to western Nevada, so plenty of upper
jet dynamics support for a convective event tonight too. Not ruling
out potentially damaging thunderstorm wind gusts. But mainly
concerned about hail and heavy rain tonight into Monday morning.
RAP/NAM low level moisture progs of +13C to +16C (or higher) line up
along/ahead of this boundary/within this surface low overnight into
Monday morning. SPC continues Slight Risk/Marginal Risk coverage
over this CWA in their Day 1/Day2 Convective Outlooks for later
tonight into the first half of Monday.

As the boundary/surface low continue to progress east and north, the
boundary layer should dry out as winds switch around to a west-
northwest wind direction. Surface pressure rises kick in late in the
day Monday and persist into Tuesday as surface high pressure gets
sandwiched in between lower pressure to the north (across southern
Canada) and the aforementioned surface front/trof that will be
stalling out across northwest Kansas and Nebraska heading into
Tuesday morning.

Without getting lost in the weeds, looking ahead to Tuesday
night/Wednesday morning, will be monitoring trends in the models for
late night WAA-forced/mid-level short-wave-lifted convection
along/north of that stalled-out synoptic-scale boundary to the south
that may be trying to work slowly back to the north Tuesday
night/Wednesday as a warm front. Beyond that, qpf clusters analysis,
complimented by the deterministic GSM`s, still showcase at least 2
or 3 more decent chances at precipitation between Thursday and the
Monday after the 4th of July holiday weekend. The pattern aloft
still tries to push the persistent downstream upper ridging over the
Great Lakes region back to the west late in the period. And that
continues to support the above to, potentially, much above normal
temperatures and humidity in the forecast. HeatRisk output and
Apparent T values will continue to be monitored. The latest wrinkle
is apparent T values running up into the low 100s tomorrow (Monday)
along and east of the SD/MN border in the afternoon. Heat Advisory
is in effect to handle this.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 619 PM CDT Sun Jun 28 2026

Terminals KABR,KATY,KPIR,KMBG

Conditions continue to be VFR, but guidance depicts sub VFR
stratus/strato-cu working its way northward into the TAF sites
later this evening and overnight along with the possibility of
patchy fog east of the Missouri River. After 06Z tonight, there
could be strong to severe thunderstorms working northeast toward
the KPIR/KMBG terminals. By the late morning/midday (~15-18),
the last of the convective potential should be shifted up
across North Dakota. Of note, periods of smoke aloft will
filter in from the southwest and track east/northeast through
the TAF period.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory from noon to 8 PM CDT Monday for SDZ008-021.
MN...Heat Advisory from noon to 8 PM CDT Monday for MNZ039-046.

&&

$$

UPDATE...MMM
DISCUSSION...10
AVIATION...MMM