396
FXUS63 KABR 162336 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
636 PM CDT Thu Jul 16 2026

.KEY MESSAGES...

- Hot and humid again Friday, even with a frontal boundary
  shifting south winds to northerly. Heat index values Friday
  in the mid to upper 90s, possibly 100F.

- Storm chances (20-40%) for Sunday with a wave that signals a
  change in the pattern to closer to average temperatures.

&&

.UPDATE...
Issued at 631 PM CDT Thu Jul 16 2026

Aviation discussion updated below for the 00Z TAFs.

&&

.DISCUSSION...
Issued at 102 PM CDT Thu Jul 16 2026

Temperatures/dewpoints are well aligned with NBM though dewpoints
started out a little higher in comparison. Like yesterday, still
expecting they will effectively mixed out with the ample
sunshine/warm temps and a lack of recent soil moisture. Low level
flow has become more southerly through the morning, increasing to
around 15-25mph.  A weak boundary crosses the region overnight into
Friday and while there is a change in winds, little change in actual
airmass with temperatures/dewpoints maintaining the current status
quo.

The upper level pattern shows the continued trend for the upper
ridge across the CONUS to gradually amplify out west, with a trough
intensifying over the eastern CONUS, giving us increasing flow out
of the northwest. This regime will set us up with a northwest flow
wave that crosses through the Western Lakes region Friday night. The
ridge re-amplifies in the wake of this wave, however is appears a
pair of ridge-riders follow for Saturday and Sunday. Those two
systems give us our precipitation chances, though the first appears
mainly as a upper/mid level deck above 14kft with a deep dry
subcloud layer.

The initial wave`s main impact for our area appears to be the high
pressure that follows, nosing down into the Dakotas it provides for
slightly more average temperatures and a slight downward trend
in humidity. Easterly mixed winds only top out around 5 to
15kts, so while afternoon humidity tanks to around 20 to 30%
west of the James valley, winds fall short of Red Flag.

Regarding smoke, an extension of the plume to the east had backed
into western Minnesota this morning, with Morris down to 1/2 mile
and the webcam west of Herman on the Traverse MN county line
indicating low visibility as well. HRRR shows this will be at its
worst through late morning, but as surface winds better organize to
southerly out ahead of a surface trough, near surface plume both
mixes out and shifts northwards. This is probably not the last we
will see in regards to surface smoke, as surface high pressure out
of Canada crosses from the Dakotas to the Western Lakes region over
the weekend. Flow around the high could eventually pivot smoke back
into the region, though at this point its uncertain as the fires in
southwest Ontario/NE Minnesota is a source region that is kind of
unusual to have a direct fetch from.

For fire weather concerns, again its pretty marginal through the
next few days as we continue to see this hot and dry weather stress
vegetation. Uncertain how widespread the moisture will be Sunday and
as such not factoring it into any sort of relief. Thus, looking at
potential days in which we`ll have lower humidity and higher wind
speeds - attention is drawn to Monday where another front moves
through. A tighter gradient and slightly stronger cold
advection for Monday means more winds. GFS mixed winds are only
about 20kts, however NBM afternoon humidity is widespread down
around 20% along and west of the James Valley. Fire Danger is
getting into the High category across much of north central
South Dakota Monday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 631 PM CDT Thu Jul 16 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period. A slim
chance (~10% or less) for a -TSRA across north central SD this
evening. There are a couple of these developing near KBIS south
towards the ND/SD state line. Will leave out of KMBG TAF for now
and continue to watch radar trends. Surface winds will gradually
shift to the north on Friday as a frontal boundary moves across
the region.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 10 PM CDT /9 PM MDT/ this evening for
     SDZ003>006-009-010-015>018-033>037-045-048-051.
MN...None.

&&

$$

UPDATE...TMT
DISCUSSION...07
AVIATION...TMT