244
FXUS63 KABR 141707 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1207 PM CDT Tue Apr 14 2026

.KEY MESSAGES...

- Mostly dry through late Thursday.

- Temperatures 15 to 25 degrees above normal Thursday (Highs: low
70s to low 80s) and low humidity. This and south winds 25 to 30 mph
results in High/Very High Grassland Fire Danger.

- Colder Friday/Saturday. Saturday high temperatures 10 to 20
degrees below normal (Highs in the 40s).

&&

.UPDATE...
Issued at 1206 PM CDT Tue Apr 14 2026

Aviation discussion below has been updated in accordance with
the 18Z TAF issuance.

UPDATE Issued at 806 AM CDT Tue Apr 14 2026

Dense fog has once again stuck around early this morning, and
surface observations show lingering areas of visibility below a
quarter of a mile, particularly in the James River Valley and
the Prairie Coteau areas. Expecting conditions to improve more
quickly than they did yesterday with westerly winds gradually
increasing to about 10 miles per hour gusting to 15 over the
next couple of hours and helping to dispell the fog. Part of the
Dense Fog Advisory has been extended to 15Z to match the new
expectations. Other than visibility adjustments to better line
up with surface observations, no significant changes have been
made to the forecast at this point.

&&

.DISCUSSION...
Issued at 1217 AM CDT Tue Apr 14 2026

Surface high to the north continues to feed cool stable air
into the region around midnight. As such, upslope favored areas
with this wind trajectory will again see fog/stratus expand over
the next few hours. Towards morning, the pressure gradient is
much weaker, winds gradually organizing around to westerly as a
surface low lifts northeast across North Dakota. 850mb
temperatures are coolest today, ranging between +3 to +9C from
northeast to southwest respectively. Will give temperatures a
slight bump above deterministic NBM which falls about 3-4
degrees below the NBM mean given the favorable mixing direction,
with the expectation that shallow low clouds/fog also mix out
with these light west winds. We fall under the influence of a
very weak surface high tonight, and on the backside, winds shift
back to southerly for Wednesday. We start to see milder air
moving in late Wednesday, with the core of the warmest air
overhead for Thursday, though with a front positioned just to
our northwest.

Its another interesting temperature forecast for Thursday with the
deterministic NBM again falling close to the 10th percentile
for high temperatures, about a difference of 8 degrees between
that and the mean. Deterministic model 850mb temperatures run
from +16 to +19C with the Canadian being a distinct cool
anomaly. The surface flow is around a low that develops over
Wyoming with an inverted trough/warm front extending up
northeast across South Dakota. This provides for a favorable
mixing environment with southwest winds south of the boundary.
The big question here is where does this surface feature set up
with the main deterministic models having a pretty tight
thermal gradient across northwest South Dakota to south central
North Dakota and any wobble in the next several runs could
translate this gradient elsewhere, and as such could result in a
forecast or forecast adjustment bust. Will leave NBM
temperatures alone Thursday for now.

A side note in regards to these conditions, it is interesting how
deep mixing is depicted in NAM BUFKIT profiles, up to
approximately 12kft out by Pierre, 10kft for KMBG and 8kft for
KABR! Shallow high/surface based altocumulus may result but
there is limited CAPE above the deep surface boundary layer, and
a substantial dry layer. All this above the 0C layer as well.
So maybe add the option for some additional gustiness with
dry/snow microburst.

That surface low translates southwards, bringing much colder air
back into the region for Thursday night/Friday. We go from 850mb
temperatures a standard deviation above climo, to a standard
deviation below climo for Saturday. Forecast temperatures reflect
this with about a 35F drop between Thursday and Friday/Saturday.

Precipitation will be pretty meager for the next few days. A
mid level deck is depicted in the NAM across south central and
far eastern South Dakota today with a deep dry layer.

We also see precipitation chances in the NBM increase Friday,
as a trough deepens to our west. Most of the model QPF appears
to come on the backside of the system as the surface low has
moved off well to the east. GFS BUFKIT profiles hint that a deep
stratus layer accompanies the change in airmasses, though if
this is the case then we`d be looking at more drizzle/sprinkles
type precipitation. And while NBM POPs are quite high, overall
the QPF is from a few hundreds to maybe 2/10ths. GEFS is in line
with this thinking with just a few members showing moisture
greater than a tenth of an inch. NBM probability of 0.25 inches
or greater is only about 40% across the northern tier of the
state, to around 20% from Pierre to Watertown.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1206 PM CDT Tue Apr 14 2026

Terminals KABR,KATY,KPIR,KMBG

Lingering morning fog has dissipated, although a few minor
visibility reductions may linger for another hour or so in the
early afternoon. Otherwise, VFR conditions are expected through
the rest of the period. Some scattered low clouds will stick
around this afternoon, but bases are expected to be above MVFR
levels. Light and variable winds are expected late tonight
before solidifying in a southerly direction Wednesday morning.
There is some signal in model guidance for some minor visibility
reductions from fog, but confidence is low on anything
widespread or any visibility reductions to MVFR status or lower.
Therefore, no mention has been put into the TAFs at this time.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.

&&

$$

UPDATE...BC
DISCUSSION...07
AVIATION...BC