749
FXUS63 KABR 160250 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
950 PM CDT Wed Jul 15 2026

.KEY MESSAGES...

- A dangerous and prolonged heat wave will persist through the
  end of the week with temperatures and heat index values
  topping out in the 90s to low 100s each afternoon. A Heat
  Advisory remains in effect.

- Elevated fire weather conditions will be possible across West
  River zones Thursday as gusty winds of 20-30 mph develop and
  minimum relative humidity values fall to between 20-25
  percent.

&&

.UPDATE...
Issued at 929 PM CDT Wed Jul 15 2026

Watching the progression of smoke as it drifts west-southwest
across central MN. Latest HRRR-smoke product does bring some
near-surface low concentration smoke into eastern parts of Big
Stone and Traverse counties by Thursday morning. Not jumping on
this quite yet in regards to insertion into the grids/forecast,
but will continue to monitor obs across western MN into the
overnight hours as 1SM to 3SM VSBYs are noted near/east of
Alexandria, MN.

Otherwise, forecast is quiet for the overnight with light
south-southeast breezes and lows dropping into the mid 60s to
low 70s for most areas.

&&

.DISCUSSION...
Issued at 156 PM CDT Wed Jul 15 2026

Upper-level ridge over the region will persist over the next few
days, continuing the above normal temperatures across the forecast
area. The Heat Advisory remains in effect through Thursday for all
counties bar Clark, Codington, Hamlin, and Deuel. Despite many areas
not expected to strictly hit Heat Advisory criteria of 100 degree
apparent temperatures, the extended duration of 95-100 degree heat
indices covering much of the forecast area is enough to warrant the
Advisory. For this same reason however, it may become somewhat
tricky to determine the appropriate end time for the Advisory.
Criteria will remain somewhat borderline through the weekend, with
apparent temperatures likely just below that 100 degree mark over
the forecast area Friday through Sunday. Looking at Heat Risk, the
probability of reaching Major Heat Risk Friday and Sunday will be
generally between 40-70% across the forecast area, with a slight dip
to around 30-50% on Saturday. For now, keeping the Advisory through
just Thursday for now, but an extension will definitely be on the
table with future forecasts.

This heat will also cause the potential for fire weather impacts,
particularly for the next couple of days. Southerly to southeasterly
flow for the next couple of days will gust up to 20 to 30 miles per
hour this afternoon, and up to 25 miles per hour Thursday. The
strongest winds both days are expected over north central South
Dakota. This also happens to be the location of the expected lowest
afternoon humidities, around 20 to 25 percent. Therefore due to this
combination of low humidity and strong wind gusts, parts of central
and north central South Dakota may see Moderate to High Grassland
Fire Danger this afternoon and Thursday. Low humidity (20-30% at the
lowest in the afternoon) will stick around over central and north
central South Dakota through the weekend, which may create
additional chances for some elevated fire weather concerns once
again.

Signals point towards relief from the heat by next week as the upper-
level ridge in place begins to break down. Ensemble clusters show a
fair degree of consistency in seeing this breakdown begin Monday.
Naturally this will lead to a cooling trend, and midweek
temperatures look to return to near normal to perhaps even slightly
below normal.

The most substantial chances for rain during the forecast period
appears to be on Sunday night into Monday. As the ridge breaks down,
strong flow aloft has the potential to sink down into the region.
The bulk of the jet streak riding down the front of the ridge will
remain to the north, but the question will be if the southern edge
will progress far enough southward to support divergence aloft over
part of the Aberdeen forecast area (likely northeastern South Dakota
to western Minnesota). Looking at the tracks of the jet streak in
mid-range ensembles, the GEFS and Canadian tend to show a more
southerly track, bringing some of the stronger winds overhead.
Conversely, the Euro supports a slightly slower breakdown to the
ridge, and keeps the jet streak just to the north. At the moment,
the environment does not appear overly favorable for severe weather
should storms develop Sunday evening, but can`t rule anything out at
this point, especially with a cold front expected to track through.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 628 PM CDT Wed Jul 15 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period, with south
to southeast breezes persisting.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 10 PM CDT /9 PM MDT/ Thursday for
     SDZ003>011-015>018-021-033>037-045-048-051.
MN...Heat Advisory until 10 PM CDT Thursday for MNZ039-046.

&&

$$

UPDATE...TMT
DISCUSSION...BC
AVIATION...TMT