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895
FXUS63 KABR 190902
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
402 AM CDT Thu Sep 19 2024

.KEY MESSAGES...

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- Dry and windy conditions are expected today. Peak gusts of around
  45 mph will be possible across north central South Dakota.

- Forecast is trending towards dry through the weekend and into next
  week with temperatures near normal.
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&&

.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
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Issued at 402 AM CDT Thu Sep 19 2024

Dry and windy conditions along with a return to seasonal
temperatures will be the main themes in the forecast during this
period. As we start off this morning, skies remain clear to partly
cloudy across the forecast area. An upper level low and it`s sfc
reflection, essentially stacked, is tracking north-northeastward
into southern Saskatchewan this morning. A cold front is draped
north to south across portions of the eastern Dakotas. This boundary
marks the delineation between a warmer, more humid air mass to the
east versus a cooler, drier air mass to its west.

This front will continue to track east into western Minnesota this
morning. Drier low level southwest to westerly flow will set up
across our CWA today. Strong winds will turn problematic with gusts
between 35 to 45 mph by midday and afternoon as the gradient
tightens. Strongest gusts look to be confined to portions of north
central South Dakota. BUFKIT sounding in that part of the state
indicate low end or marginal wind advisory type wind speeds from mid
morning through mid afternoon. Peak mean winds within the mixed
layer indicate a range from 35-40kts. HREF probabilities of reaching
or exceeding wind gusts of 45mph are mainly confined to northwest
South Dakota or just to the west of our CWA. However, NBM
probabilities for those same conditions paint a bullseye across
parts of Corson and Dewey Counties; more probable for western and
central portions of those counties. Decided to be cautious and issue
a Wind Advisory for Corson and Dewey from 12-21Z today. Fire weather
concerns are tempered today due to the cooler temperature readings
in place. Worse case scenario should see minimum relative humidity
values fall to between 25-30 percent this afternoon across our West
River zones.

The remainder of the period should stay relatively quiet. Sfc high
pressure will begin building into the area tonight into Friday after
the upper trough axis exits east of our region. Cooler temperatures
infiltrate the area tonight as readings fall into the 50s overnight.
A fairly warm Friday is anticipated with daytime highs back into the
80s to perhaps some low 90s. NBM probabilities of reaching or
exceeding 90 degrees remain confined to our southwest zones, south
and west of the Pierre area where values range from 30-50 percent.
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.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
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Issued at 402 AM CDT Thu Sep 19 2024

Trends in the long term include a continued southwards track of the
weekend Colorado low, resulting in diminishing POP chances with
expected dry conditions for most of the CWA this weekend. The main
reason is a stronger high pressure system that tracks closer to
North Dakota and then into the western lakes region.  Models
thereafter diverge on handling upper level features though the
longwave trough axis passes overhead early Tuesday. That either
results in a progressive pattern with an upper ridge overhead (GFS),
or a cut-off low over the Southern Plains (EC/Canadian). Regardless
of the upper level pattern outcome, for the most part this would
translate into dry conditions for the region, with the NBM POPs only
around 10-15%. As for temperatures, there is a brief surge of warm
advection Friday night with 850mb temperatures up to a standard
deviation above climo, followed by a cold frontal passage that
brings readings closer to a mid-september climatology. There are no
surges of anomalous airmasses thereafter, though again, confidence
in the temperatures for next week diminishes as models diverge.
Still looking at an NBM range in the 25th/75th percentiles of about
5 to 8 degrees for both highs and lows, though the NBM is trending
upwards the highs/lows 50th percentiles over the last few runs.
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&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1241 AM CDT Thu Sep 19 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail at all 4 terminals for this 24 hour
forecast period. Wind direction will become southwest to west
across the area this morning. Gusty conditions will develop with
speeds up to or just in excess of 30 knots from around mid
morning through late this afternoon.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
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SD...Wind Advisory until 3 PM MDT this afternoon for SDZ003-015.

MN...None.
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&&

$$

SHORT TERM...Vipond
LONG TERM...Connelly
AVIATION...Vipond