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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KABR 201726 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1226 PM CDT Sat Apr 20 2024

.KEY MESSAGES...

- Near to below average temperatures hang on today and tonight.
  Near to above average temperatures Sunday through Friday.

- The precipitation potential for Monday keeps diminishing, but
  an active pattern may develop for the second half of the
  upcoming week.

&&

.UPDATE...
-- Changed Discussion --
Issued at 1223 PM CDT Sat Apr 20 2024

Aviation discussion updated below for the 18Z TAFs.

UPDATE Issued at 1011 AM CDT Sat Apr 20 2024

Continue to watch stratus trends on satellite as an area of lower
end VFR cloudiness moves southeast across the region. Adjusted
sky grids to better align with current trends, which features
clearing skies from north to south as the day progresses.
Otherwise, no big changes to the forecast as we will see highs in
the upper 40s to low 50s, with northwest breezes lower than what
we`ve seen the past couple days.
-- End Changed Discussion --

&&

.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 303 AM CDT Sat Apr 20 2024

Short term models agree on an elongated trough over the Northern
Plains today, which will keep winds out of the northwest aloft. An
elongated surface high moves in from the northwest and will be
positioned from MT southeastward into the Central Plains by 12Z
Saturday. By Sunday morning, this high will sink south/southeast and
will be centered over the Central Plains, leaving the Northern
Plains in a surface ridging pattern. A positive tilted ridge moves
in aloft through the day, ahead of our next trough. This overall
pattern will give us dry conditions through the short term.

Surface winds remain out of the northwest today and with a much more
relaxed pressure gradient, will not be as windy as what we saw the
past couple of days. However, it won`t be totally calm. Soundings
still show a dry inverted v look to them this afternoon as the
colder air steepens the low level lapse rates along with daytime
heating. The only difference is winds at 850mb are 20kts or less to
mix into. RAP soundings along with HRRR show sustained winds 10-
15kts at most across the area this afternoon with gusts up to 20kts.
NBM shows a tad higher so added these to the mix to bring them down.
Winds remain on the low side tonight through Sunday morning before
increasing around and west of the Mo River Sunday afternoon, due to
the incoming trough.

Temps will be warmer than what we saw yesterday as there will be
more sun to work as RAP indicates temps in the upper 40s to around
50, which matches pretty well with NBM. Clear skies and light winds
tonight will promote radiational cooling and this should help temps
drop into the 20s. I did drop them a few degrees from the NBM given
this scenario but will need to be monitored as there is a chance
they could dip even lower. With the ridge moving in for Sunday at
both the surface and aloft, winds will switch out of the southwest,
bringing in warmer air, with highs rebounding back in the upper 50s
to the mid 60s.

&&

.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 303 AM CDT Sat Apr 20 2024

This morning, the extended is being influenced by a decidedly cold
(outlier) model and its ensembles; the GFS/GEFS. Its cold rendition
of temperatures throughout the extended is influencing the (grand)
ensemble guidance, causing it to run a touch cool, compared to the
EC and Canadian models and their respective ensemble systems.

Heading into the start of the work week, there is still an area of
low pressure being progged to work across the northern tier states
(and far southern Canada), influencing the northern plains Monday
into Tuesday. The trend over the past three mornings has been for
PoPs to decrease. This morning, PoPs for Monday/Monday night are now
down to ~15-30%, where WAA-forced precipitation would be the primary
cause of precipitation. Surface pressure fields suggest the warm
front is pushing through the CWA from west to east during the day
Monday, with the potential for some blustery west/northwest winds to
materialize, at least throughout the Missouri River valley, before
the end of mixing/heating. Still looks like the cold front then
sweeps south through the CWA sometime Monday night into Tuesday
morning, before high pressure both at the surface and aloft sets up
shop over the northern plains. There is still quite a bit of
dissonance amongst model camps for just how to handle the western
CONUS longwave troughiness and associated shortwaves that shoot out
of it and move across the nation`s mid-section (ranging from the
southern plains all the way up into the northern plains) from
Wednesday night onward. It does still have the markings for being an
active period of precipitation potential.

Minus the aforementioned GFS/GEFS outlying cold solution this
morning, the extended becomes a multi-day period of warm
temperatures (at least) in the 60s and 70s for much of the CWA. Will
have to see if this morning`s GFS/GEFS cold solution is just a one
hit wonder, or if it will stay the course and other model camps
eventually join it. Usually, when systems track from the Pacific
Ocean across the CONUS (no connection to Canada-sourced polar cold
air), they bring with them a warmer air solution, like the
EC/Canadian models/camps. So, right now, warmer conditions from
Tuesday through Saturday seems like a "good bet".

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
-- Changed Discussion --
Issued at 1223 PM CDT Sat Apr 20 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period.
-- End Changed Discussion --

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...TMT
SHORT TERM...MMM
LONG TERM...Dorn
AVIATION...TMT