Lacy, South Dakota Weather Forecast Discussion

487
FXUS63 KABR 271742 AAC
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1242 PM CDT Sat Sep 27 2025
.KEY MESSAGES...
- Above normal temperatures (10-15 degrees above normal) plus dry
and windy conditions will return for the end of the weekend into the
first half of next week.
&&
.UPDATE...
Issued at 1238 PM CDT Sat Sep 27 2025
The aviation discussion has been updated for the 18Z TAFS.
UPDATE Issued at 1017 AM CDT Sat Sep 27 2025
The forecast for the remainder of today remains on track with no
changes expected at this time.
&&
.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 300 AM CDT Sat Sep 27 2025
A dry cold front is passing through the area early this morning, but
gusty northwesterly winds behind have been reaching 20-30 miles per
hour. These stronger winds remain fairly transient, sticking around
only for an hour or two as a surface high pressure center continues
to slide east into the CWA. Cold air advection aloft will help keep
highs closer to normal today, reaching the low to mid 70s across the
forecast area.
An upper-level ridge will build in tonight and Sunday, allowing for
an abnormally warm air mass to return to the forecast area. Of note
are 500mb heights and 850mb temperatures, both of which are modeled
to be well above the 90th percentile for late September, at ~5280m
and 20 degrees Celsius respectively. This setup will support highs
north of 80 degrees across the forecast area, 10-15 degrees above
normal for late September. As the ridge-supported surface high
pressure center moves further east Sunday, a tightening pressure
gradient on the backside will support the return of southerly winds
of 15 to 20 knots, gusting up to 30 knots. The main impact areas are
over central into parts of north central South Dakota, but nearly
all of the CWA is forecast to have a few hours of 25 knot gusts or
greater Sunday afternoon. At this time, the NBM does not give any
significant probabilities for a Wind Advisory (sustained winds of 30
miles per hour or gusts to 45 miles per hour) to be issued on
Sunday.
Smoke is also a minor concern in the short-term forecast. Current
air quality remains at Moderate levels, meaning impacts are likely
only to those sensitive to smoke. Still, additional smoke will move
into the area today, mainly expected over central South Dakota. Most
of the smoke will remain aloft, but enough could still make it to
the surface to impact those sensitive to smoke. At this point, not
anticipating any visibility reductions due to haze, and air quality
is expected to remain within the Moderate threshold.
&&
.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 300 AM CDT Sat Sep 27 2025
No major changes for the forecast next week. Mild temperatures
and the winds are the main `concern`. A broad ridge overhead to
start the week is going to be very slowly supplanted by an upper
trough developing over the Pacific Northwest, but that may take till
next weekend before transiting far enough east that we start to get
into the better chances for moisture. Thus...until then its a mainly
dry pattern with a series of southwest flow shortwaves. The first
plume of elevated moisture from the southwest monsoon comes in late
Monday/Tuesday with the current upper low lifting northeast and
becoming an open wave. BUFKIT profiles feature moist adiabatic
lapse rates above 700mb/10kft. The next few waves after that are
weaker and related to plumes of moisture coming in from the Pacific.
As for temperatures, 850mb temperatures are expected to stay above
normal at approximately a standard deviation above climo if not
higher. Thus, all next week temperatures will be running about 15 to
20 degrees above normal for highs and 15 to 25 degrees above normal
for lows thanks to persistent winds. In fact, we are very close to
record warm low temperatures for the week.
Winds will also be rather persistent. 1/2km winds are up around 30-
40kts Sunday night, Monday night and Tuesday night as the boundary
layer decouples.  There will also be a 10mb gradient from northwest
to southeast across the state. The only thing about the winds is the
mixing efficiency with south/southeast low level flow and warm
advection. As such, see no reason to deviate from NBM. Winds will
subside Wednesday with a surface trough passage.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1238 PM CDT Sat Sep 27 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions will prevail all terminals for this TAF cycle.
Winds will remain light the rest of today into this evening. Any
northerly wind component left over through late this afternoon and
evening will become southerly tonight into Sunday. A tightening
gradient Sunday morning will lead to gusty southerly winds of
20-25 kts by late in this forecast period.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Vipond
SHORT TERM...BC
LONG TERM...07
AVIATION...Vipond

NWS ABR Office Area Forecast Discussion