Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 260547 AAC

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1147 PM CST Wed Nov 25 2020

Issued at 1142 PM CST Wed Nov 25 2020

See below for an aviation forecast discussion for the 06Z TAFs.

UPDATE Issued at 711 PM CST Wed Nov 25 2020

Out ahead of this approaching surface trof/frontal boundary, with
the setting of the sun and the decoupling of the boundary layer,
low stratus and some areas of fog are making a surge north-
northwestward along and east of the Prairie Coteau in northeast
South Dakota into west central MN this evening. Fully expecting
these two phenomena (low clouds and fog) to persist overnight
until the surface trof overtakes them and scours them out when
winds switch from the south to the northwest. Updates are out to
re-introduce low clouds and to add some fog to the far eastern
forecast area (I-29 corridor over into west central MN).

UPDATE Issued at 549 PM CST Wed Nov 25 2020

See below for an aviation forecast discussion for the 00Z TAFs.


.SHORT TERM...(This Evening through Thursday Night)
Issued at 317 PM CST Wed Nov 25 2020

High pressure will exit the area to the east by this evening ahead
of an approaching frontal boundary. This front looks to track across
the CWA during the overnight hours, resulting only in a wind shift
to northwest winds. High pressure will begin to nose its way back
over the area Thursday morning before another weak front drops in
from the northwest. This front tracks across the CWA Thursday
evening, with high pressure then building in more solidly over the
area during the overnight hours. All in all, dry and mild conditions
will continue. Low temperatures tonight will be in the lower to mid
20s, with highs on Thursday in the upper 30s to the mid 40s. Lows
Thursday night will be in the upper teens to lower 20s.

.LONG TERM...(Friday through Wednesday)
Issued at 317 PM CST Wed Nov 25 2020

The mild temperatures will continue through Saturday. 850mb
temperatures on lighter westerly flow will rise into the 7 to 11C
range by 00Z Sunday. We continue to forecast on the higher end of
available guidance, with temperatures expected to rise into the 50s,
with upper 40s over the Sisseton Hills. These values are still 5 to
10 degrees below records that are mainly in the low to mid 60s
across the region.

We are expecting dry weather through the entire extended. There are
a couple of periods when precipitation may be possible to our north,
like Sunday when a cold front crosses the area. Much of the energy
and moisture will remain well to our north. We will still have
plenty of clouds, stronger northwest winds, and colder temperatures.
850mb temperatures will drop nearly 20C between 06Z Sunday and 00Z
Monday. Highs on Sunday will be in the 30s. Continue to highlight
breezy northwest winds Sunday as the surface high sinks across
western SD through the day. Stronger winds will return Monday
evening as the pressure gradient increases across our area as the
surface ridge exits across MN Monday evening, and the next trough
moves into western South Dakota. Uncertainty increases significantly
beyond Monday evening as we get 500mb a northern/southern stream
merger to our southeast, which looks to produce a significant storm
system for much of the northeastern U.S.


.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1142 PM CST Wed Nov 25 2020


Interruptions in VFR flying weather are likely to continue during
the TAF valid period. The KATY terminal continues to experience
fog and low clouds. But, per satellite imagery, it`s possible VFR
weather could be returning to KATY by as early as 07Z or 08Z, as
stronger westerly component winds clear everything out.

Meanwhile, KMBG/KPIR/KABR may see a couple brief bouts with sub-
VFR post cold-frontal stratus by 12Z, for a few hours before
conditions clear off, and then again after 00Z Friday.




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