401
FXUS63 KABR 021324 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
824 AM CDT Sun Aug 2 2026

.KEY MESSAGES...

- A Heat Advisory has been issued today for Corson, Dewey,
  Stanley, and Jones counties. Heat indices upwards of 100
  degrees will be possible over that area this afternoon.
  Temperatures are set to cool down to below normal for Tuesday
  and Wednesday.

- Storms may develop along a cold front moving over the area
  late Monday into early Tuesday. A Marginal Risk (Level 1 of
  5) is in place for parts of northeastern and central South
  Dakota, as well as western Minnesota. A Slight Risk (Level 2
  of 5) clips part of far northeastern South Dakota and western
  Minnesota. With these storms, the main severe threats will be
  hail of one to two inches in diameter and wind gusts of 60 to
  70 miles per hour.

- Above normal temperatures and strong southerly wind gusts
  will combine to create elevated fire weather concerns over
  central and north central South Dakota Sunday, when gusts
  reach as high as 30-40 miles per hour and relative humidity
  falls below 30 percent. Elevated fire weather concerns return
  over that area Monday, with gusts of 35-45 miles per hour west
  of the Missouri River and humidity again below 30 percent.

&&

.UPDATE...
Issued at 814 AM CDT Sun Aug 2 2026

Continuing with Heat Advisory (NPWABR) and elevated Grassland
Fire Danger concerns (SPSABR), west river, today. No changes
planned to the forecast; hot and windy this afternoon.

UPDATE Issued at 621 AM CDT Sun Aug 2 2026

Aviation discussion updated below for the 12Z TAFs.

&&

.DISCUSSION...
Issued at 231 AM CDT Sun Aug 2 2026

Above normal heat will push high temperatures and heat indices
upwards of 100 degrees this afternoon. Therefore, a Heat Advisory
has been issued for Corson, Dewey, Stanley, and Jones counties.
Southerly winds will strengthen today, gusting up to 30 to 40 miles
per hour by the afternoon. These strong gusts will mainly be along
and west of the James River Valley. When combined with the heat over
central and north central South Dakota, fire weather concerns become
elevated. The Grassland Fire Danger Index will reach Very High
levels west of the Missouri River as a result. Afternoon humidity is
expected to fall just shy of the 20 percent or lower criteria for a
Red Flag Warning, so opting for a Special Weather Statement to cover
the near-critical fire weather threat this afternoon. Only other
item of note today is that wildfire smoke from the Pacific Northwest
will continue to move over the region today and into at least
Monday. Smoke is expected to remain mostly aloft, creating hazy
skies. Still, near-surface concentrations could be enough to cause
minor visibility reductions as well as drop air quality to Moderate
levels, impacting those sensitive to smoke.

An upper-level trough will move over the Northern Plains beginning
Monday. As a result, a cold front will move over the region Monday
into early Tuesday. Storms may develop along this front, and storms
that do form have the potential to be severe. The main obstacle to
storm formation will be a mid-level cap in place. This cap is
strongest over central South Dakota and becomes weaker moving to the
northeast. Therefore, the area with the greatest chances for severe
weather will be over northeastern South Dakota and western Minnesota
Monday evening. There is still some disagreement amongst the model
soundings on just how much of a cap will be over the area, with some
showing little to none. Look for this to come into further focus
over the next couple of forecast cycles as the event draws nearer.
The main severe threats out of storms that form will be hail and
wind. On the hail side, CAPE/Shear combo of roughly 1000-2000 J/kg
and 40-50 knots at 0-6km respectively will be in place. Mid-level
lapse rates of up to 8 C/km will also be in place, so hail will be a
potential threat. Decent confidence in the potential wind threat as
well due to a fairly strong signal for DCAPE > 1000 J/kg and low-
level lapse rates approaching the dry adiabatic lapse rate where the
cap has been eroded. At this time, there is a Slight Risk over parts
of northeastern South Dakota and western Minnesota as well as

As the cold front passes over north central South Dakota Monday
afternoon, winds turn northerly and will increase once again. Gusts
as high 35 to 45 miles per hour will be in place Monday afternoon,
once again mainly over central and north central South Dakota. The
latest NBM guidance gives a roughly 30 to 50 percent chance for
gusts to reach above 45 miles per hour Monday afternoon over Corson
and Dewey counties, so the potential for a Wind Advisory will be
monitored with future forecasts. These strong winds and the
continuation of above normal temperatures Monday will once again
create elevated fire weather conditions over central and north
central South Dakota. The Grassland Fire Danger Index will be at
High to Very High levels.

Behind the cold front Tuesday and Wednesday, below normal
temperatures will take hold. Highs both of those days will be in the
70s to low 80s across most of the forecast area, which is about 5-10
degrees below early August normals. The upper-level trough will move
out of the area by the end of the week, with a broad, weak ridge
expected to take hold of the region. This will lead to the likely
return of above normal temperatures, particularly over central and
north central South Dakota.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 621 AM CDT Sun Aug 2 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period. Gusty
southerly surface winds will develop by late morning and persist
into the early evening hours, with gusts from 25 to 30+ kts.
Low-level wind shear (LLWS) looks to develop overnight across
the region and have inserted mention of this where/when
appropriate for KABR/KMBG/KPIR.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 9 PM CDT /8 PM MDT/ this evening for
     SDZ003-015-033-045.
MN...None.

&&

$$

UPDATE...10
DISCUSSION...BC
AVIATION...TMT