Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 071812 AAC

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
112 PM CDT Fri Oct 7 2022

Issued at 1235 PM CDT Fri Oct 7 2022

Aviation discussion updated below for the 18Z TAFs.

UPDATE Issued at 1027 AM CDT Fri Oct 7 2022

Let the Freeze Warning expire at 15Z this morning as temperatures
continue to climb at and above the freezing mark. Most areas
experienced a hard, killing freeze overnight into this morning,
thus ending the growing season. The forecast for today is on track
and few changes are needed. Will see mostly sunny skies and light
winds as the surface high remains in place. There were a few
patches of low clouds/fog around some of the warmer lakes this
morning, but that continues to burn off in those locations.
Temperatures will remain on the cool side, with highs in the upper
40s to low 50s for most areas.


.SHORT TERM...(Today through Saturday Afternoon)
Issued at 256 AM CDT Fri Oct 7 2022

Main concern in the very short term is the continuing drop in temps
below freezing for much of the CWA this morning. However, we have
been watching lower cloud cover over Big Stone and Traverse counties
from some shortwave energy aloft, keeping the temps above freezing
at this point in time. HREF keeps these clouds hanging around over
our eastern CWA through 12Z before pushing east. We will keep the
freeze warning for these counties as of now with the overall freeze
warning continuing through 10AM. Otherwise, most of the CWA is
mostly clear allowing for radiational cooling to continue with clear
skies and light winds.

Otherwise, a pretty quiet short term forecast with a 1038mb high
moving down from Canada (center now over ND as of 6Z) through the
day before shifting east/southeast tonight into Saturday. The
MSLP/height of this high is 99.5% higher than CFSR climo at 850mb,
according to NAEFS! With this high overhead, skies will be clear
across much of the CWA through Saturday, except for those lingering
clouds early in western MN today as mentioned. We will see some high
clouds move in from the north with our next system but not until
Saturday late afternoon and evening. With quite the amplified ridge
out west and trough to our east/northeast, we will continue with
northwest flow aloft. Highs for today will remain cool ranging in
the upper 40s to the mid 50s with light and variable winds. Surface
winds will shift out of the west/southwest overnight, allowing for
very weak WAA to move in as temps at 850mb will be ~3-6C above zero
and 925 temps ~7-9C above zero at 12Z Saturday per deterministic
models. With clear skies expected, radiational cooling will occur
but temperatures should not be as cold as this morning. Lows will be
chilly in the mid-upper 20s/lower 30s across the area. This warmer
air will allow our temperatures to reach back up to around average
for Saturday with highs in the 60s. An increase in winds expected
Saturday afternoon and evening from the exiting high and incoming
low as pressure gradients steepen lightly, with gusts up to 25 mph,
mainly around the Coteau.

.LONG TERM...(Saturday Evening through Thursday)
Issued at 256 AM CDT Fri Oct 7 2022

Ensemble output plus deterministic runs of the GSM`s support the
extended being dominated by northwest flow over this CWA while an
anomalously strong upper level ridge is over the west coast. The
pattern looks to go nearly meridional a couple of times in this
highly amplified/blocky pattern.

About the only time when there might be some precipitation chances,
right now, seems to be anchored on Tuesday/Tuesday night. There is a
signal in the ensemble/deterministic solutions showing up for a low
pressure system to slide down the back-side of the upper ridge and
sweep through the northern plains region while
deepening/strengthening. Models do vary some on placement/strength
of this feature, and so far, the blend of models has not generated
much for precipitation chances over this CWA with this feature.
Otherwise, Saturday night through Thursday is a dry forecast period.
There is one system progged to work southeastward out of Canada and
into the Great Lakes region late in the weekend. Models dragging a
back door cold front south and west through the CWA Sunday/Sunday
evening, which will briefly set up a period of weak low level CAA
mainly across the eastern forecast zones Sunday night into Monday.
Other than that, low level thermal progs are set to a slow and
steady WAA pattern in the out periods until that potential
Tuesday/Tuesday night (timing subject to change?) system moves
through, bringing another push of cooler air for mid-week.


.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1235 PM CDT Fri Oct 7 2022


VFR conditions are forecast through the TAF period.




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