123
FXUS63 KABR 191854
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
154 PM CDT Sun Jul 19 2026

.KEY MESSAGES...

- Heat advisory remains in place however cloud cover has been
  helping hold temperatures down for much of the morning.

- Fast moving storms this evening/overnight (20-40%). Initially
  a large hail (up to 2" diameter) threat for north central
  South Dakota, transitioning to a wind threat (60 to 80 mph
  gusts) as storms shift east-southeast through the overnight.

- Heightened Fire Weather threat for Monday. Lightning starts
  from storms tonight are possible. Northwest winds of 25 to 40
  mph during the day, with afternoon humidity down to around
  20% across central/north central South Dakota, 25-35% across
  the northeast/western Minnesota.

- Smoke from western wildfires could move into central/north
  central South Dakota behind the front. Minor impacts to
  visibility.

&&

.DISCUSSION...
Issued at 146 PM CDT Sun Jul 19 2026

Cloud cover has helped suppress temperatures thus far, though
humidity has likewise responded higher. Comparing current readings
to NBM by 18Z, were about 6-10 degrees too cool from Mobridge to
Miller and points east, while central South Dakota is on track. More
sun moving into north central South Dakota and eventually the James
valley, so will leave headline in place but trended Highway 281 and
points east temperatures a few degrees cooler as mid clouds head
that direction.

Focus is on severe weather potential later this evening. We are at
the southern periphery of a rather stretched, weak wave thats over
North Dakota. Flow in the mid levels associated with this feature is
increases to 40kts between 00-03Z out of the west northwest. At the
surface, we have decent southerly flow, which has picked up the
humidity from recent rainfall. Dewpoints across central/north
central South Dakota are running about 3-5F higher than what was
predicted from the previous run of the NBM so a little richer
environment for convection, with the NAM/HRRR at around 2500-
3000j/kg. That said, BUFKIT profiles suggest deep mixing is still
required for surface based convection (up to 8kft). There is also a
fetch of dry air above 500mb. Aside from the southerlies in the
boundary layer, straight line hodographs and about a 40kt storm
motion means still looking at a wind threat once storms get
organized.  CAMS are mostly pointing to development 01-03Z across
north central South Dakota, though a few cells may briefly develop
in central South Dakota. The north central activity will then
rapidly move towards northeastern South Dakota through about
midnight, but it should be noted that CAMS are pointing
towards more isolated to scattered coverage.

The RAP/HRRR are bringing in smoke behind the frontal system as
well, with the Air Quality Forecast Guidance Viewer likewise pointing
to smoke migrating northwest to southeast across the Dakotas.
Concentrations are significantly lower in comparison to what the east
coast has been dealing with. Elevated smoke is also predicted and
have adjusted sky cover to match. Unsure of thickness and what
impact it will have on mixing which will thus effect
temperatures/humidity and winds.

Regardless, NBM temperatures/winds/humidity currently point to Red
Flag for north central South Dakota, which mostly missed out on
morning precipitation. While Mobridge did get 2" of moisture about 10
days ago, Gettysburg fell shy of an inch and Lowery SDSU mesonet has
only picked up 0.17" for the month. Grasses on webcams are getting
dry and we`ve had some fires already across north central South
Dakota, and despite rainfall potential (which is really very
limited in coverage and amounts) issued a Red Flag for Monday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 146 PM CDT Sun Jul 19 2026

Terminals KABR,KATY,KPIR,KMBG

Just some mid and high level clouds today with a south wind. Late
afternoon/evening look for storms up around the KMBG area, with the
focus shifting rapidly south and east. A frontal passage follows,
though for a bit there will also be some LLWS ahead of the front for
KATY. Winds shift to the northwest in the morning and pick up
through the day. There may be some smoke behind the front, currently
estimated to be VFR for KPIR/KMBG.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 9 PM CDT /8 PM MDT/ this evening for
     SDZ003>006-009-010-015>018-033>037-045-048-051.
     Red Flag Warning from 3 PM CDT /2 PM MDT/ to 9 PM CDT /8 PM
     MDT/ Monday for SDZ003-004-009-015-016.
MN...None.

&&

$$

DISCUSSION...07
AVIATION...07