Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 231655 AAB

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1055 AM CST Thu Nov 23 2017

Issued at 1053 AM CST Thu Nov 23 2017

No major changes to the forecast. Did up sky cover some as plenty
of cirrus is flowing over the mid level ridge south into the
forecast area. Temperatures look okay for now.


.SHORT TERM...(Today through Saturday Afternoon)
Issued at 357 AM CST Thu Nov 23 2017

Upper level ridge building into the region, along with westerly
winds will bring much above normal temperatures into the region
today. Highs temperatures will range from the upper 40s, in
western Minnesota, to the upper 60s and low 70s, along and west of
the Missouri Valley. Am a bit concerned with our highs in the
James Valley where our 0Z sounding shows a substantial inversion.
The NAM keeps the inversion in the valley until after peak
heating. A few CAMS support the idea of warm temps along the
western rim of the valley, and on the eastern side of the Sisseton
Hills. Thus have lowered highs slightly in the eastern CWA from
the previous forecast. A few locations will likely see record to
near record high temperatures today. Record highs for
Thanksgiving will be possible for a few locations as well.

Warm temperatures will remain over the region tonight with lows only
in the 30s and 40s. An upper level trough and surface front will
cross the region on Friday. This system will bring very strong
northwesterly winds, along with a chance for light rain. The
strongest winds will likely occur between 12-18Z, for our western
CWA, and 18-0Z for our east. Buffer soundings, along with half km
winds support advisory level winds for the region on Friday. Pcpn
looks best in the eastern CWA during the morning hours. While 925
and 850 mb temps cool off on Friday, highs will still reach the 50s.

A Canadian high pressure sliding southwest across the region on
Saturday will bring cooler temperatures with highs in the 40s and
low 50s.

.LONG TERM...(Saturday Evening through Wednesday)
Issued at 357 AM CST Thu Nov 23 2017

The larger-scale signal for flow pattern in the models remains
unchanged in the out periods, a positive PNA pattern (ridge/warm out
west and trof/cool out east) with this CWA situated in between in,
more often than not, some form of northwest flow aloft, which
promotes a prevailing dry forecast with fluctuations back and forth
between periods of warmer than normal and cooler than normal

The 00Z GSM output tonight continues to leave questions surrounding
precip potential Monday night through Tuesday night unanswered. In
this installment, the ECMWF has returned to looking more like
solutions from a couple of nights ago, leaving a much weaker more
progressive shortwave to move through the northern plains, while
taking a separate/larger chunk of longwave trof energy southeastward
into the southern plains early to mid week next week. The GFS looks
similar to the ECMWF tonight, while the Canadian model takes a turn
at being the strongest/slowest and farthest north solution in
handling the treatment of said energy eastward across the country.

Monday night through Tuesday night is now moving into the day 5/day
6 portion of the forecast, but there is just as much uncertainty now
regarding strength and track of this energy moving through the
western CONUS ridge and out into the middle section of the country
as there was back when it was in the day 7/day 8 timeframe. For now,
it`s safe to say "there is still a signal" lurking in the out
periods for some precipitation potential early next week. Will
continue to wait out the models and see if they start to come into
better agreement/timing/strength of low pressure energy early
next week.

As for temperatures, much above normal warmth (1.5 to 2.5 standard
deviations above normal under the NAEFS Ensemble SA standardized
anomaly table) appears to reside over this region until Monday night
when colder air is progged to move in from the north and stick
around for a couple of days. That being said, these cooler
temperatures will probably end up being right around climo-normal
for late November/early December.


.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 518 AM CST Thu Nov 23 2017

There is still a stripe of IFR stratus (was extending from
Devil`s Lake, North Dakota all the way down to near
Ellendale/Gwinner, North Dakota areas earlier) hanging out north
and east of KABR/KATY this morning. It`s more likely that these
two terminals remain VFR this morning, but will continue to
monitor for the need to introduce, perhaps, a couple hours-worth
of tempo IFR here during the morning hours. Guidance supports any
sub-vfr cloudiness either dissipating this morning or moving off
to the east into Minnesota.

Otherwise, good VFR is the expectation, once again, over the next
24 hours. Worth noting, Friday morning, winds will become
northwesterly at KMBG/KPIR and acquire a notable up-tick in winds
speeds. Similar conditions will move over into the KABR/KATY areas
by early Friday afternoon. Something to be aware of.




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