Brainard, South Dakota Weather Forecast Discussion

054
FXUS63 KABR 051721 AAC
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1221 PM CDT Sun Oct 5 2025
.KEY MESSAGES...
- Peak wind gusts of 30 to 40 mph are expected to be widespread
today with some gusts closer to 50 mph for the northeast tier of
South Dakota including the Sisseton Hills region. Winds will
diminish by this evening.
- Locally patchy frost is a possibility for Monday morning and
Tuesday morning mainly for north central South Dakota.
&&
.UPDATE...
Issued at 1013 AM CDT Sun Oct 5 2025
Cancelled most of the wind advisory early today as wind gusts have
been topping out below 45 mph and will continue to diminish as the
low pulls off to the north and east. Left the advisory in place
for the highest elevations of the Coteau in Marshall and Roberts
counties where there have been isolated gusts to 45 to 50 mph.
&&
.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 235 AM CDT Sun Oct 5 2025
As of 2am, light rain showers are moving northward over portions of
south central and east central SD with temps in the mid to upper 70s
ahead of the cold front and upper 50s to the lower 60s in central
SD, behind the front. The axis of the negative tilted shortwave is
over the western half of SD/NE into WY with the LLJ currently
positioned over the James River Valley and eastward into MN with
speeds of 40-65kts, highest over and east of the Coteau. This LLJ
has kept this area gusty with speeds ranging from 30 to 40 mph.
Adding in southerly flow at the surface has lead to downsloping
winds along the the eastern side of the Coteau with reports of 45mph
up to 55mph, with the highest reports in Peever and Sisseton.
Downsloping winds will continue through the early morning before
diminishing a bit as winds turn more westerly. Surface map indicates
the center of the low pressure extending from southeastern
ND/northwestern MN by 12Z with its cold front extending southward
through eastern SD. By this time, the LLJ will really only shift
slightly east. A secondary, more quicker cold front, will swing
northwest to southeast over the CWA behind the first cold front with
both fronts exiting the eastern CWA by this afternoon, merging to
our east/southeast. Behind the system, a high pressure system will
move in from the northwest, over central MT by 00Z Monday and
directly over the Northern Plains by 12Z Monday. This high will
shift slightly southeast, but still dominate the region by Monday
evening.
CAMs agree well and indicate isolated to scattered light rain
showers continuing to about ~17Z mainly along and west of the
Missouri River. Up to 0.10" of of additional rainfall is possible,
highest over western Corson County.
With the exiting low and and incoming high, pressure rises of 4 to
10mb/6hr is noted by the GFS, highest over north central SD, with
the highest rises shifting a bit eastward by the afternoon. Adding
in CAA right behind the front will help steepen low level lapse
rates. I did a blend of 2 parts NBM, 1 part NBM90 to show for the
potential of these higher wind gusts. So forecasted wind gusts range
from 30-40 mph with higher gusts of 40-50mph over the northeastern
tier of SD (including areas over and along the Coteau) through the
afternoon. A Wind Advisory has been issued for McPherson, Brown, and
Day Counties from 12-20Z. I extended the previous Wind Advisory, for
our eastern/southeastern counties for the downsloping winds, until
20Z as well. The stronger CAA/pressure rises (and steeper pressure
gradients) shift east with the low by late afternoon into the
evening which will diminish the winds west to east across the CWA at
this time and becoming light Monday as the high moves in overhead.
With northwesterly flow and a cooler air mass behind the departing
system, highs will only be in the upper 50s to the lower 60s over
central SD with highs in the upper 60s to the mid 70s over eastern
SD, which those temps will fall behind the fropa. Lows will dip down
into the upper 30s to the mid 40s tonight. Patchy frost is possible
over north central SD early Monday morning as well. Highs for Monday
will feel more Fall like, ranging in the upper 50s to the lower 60s.
&&
.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 235 AM CDT Sun Oct 5 2025
Frost remains the primary concern, and while deterministic NBM is
pretty frost free, there may be a warm bias, as we have endured a
fairly long duration warm period for the last several weeks. Monday
night still looks like an ideal setup, with high pressure directly
overhead during the day Monday, highs will only get to around 60F.
As the high moves east, winds shift around to southwesterly, but
remain light. No mid level moisture is noted. The only thing that
gives me pause is that the ground has quite a bit of residual heat,
as the SDSU meso-network has 4" soil temperatures well into the 60s
if not the low 70s. Even deterministic guidance isn`t really
supportive of frost. Despite all this, given the time of year, and
the meteorological setup, feel its best to go with the lower
percentile temperatures in the NBM and worked more spread frost
mention into the CWA. Overall NBM probabilities for a low
temperatures below 36 degrees Tuesday morning is about 50/50 along
the ND/SD state line in north central South Dakota and only about
20% down between Pierre and Redfield. Overall doesn`t look like a
season ending widespread frost... and the rest of the forecast is
back to featuring above normal temperatures (5-15 degrees) and
relatively little chance for moisture.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1220 PM CDT Sun Oct 5 2025
Terminals KABR,KATY,KPIR,KMBG
MVFR cigs are expected to improve to VFR by this evening. Gusty
northwest winds will also diminish this evening.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 3 PM CDT this afternoon for SDZ007-008.
MN...None.
&&
$$
UPDATE...20
SHORT TERM...MMM
LONG TERM...07
AVIATION...20

NWS ABR Office Area Forecast Discussion