923
FXUS63 KABR 240000 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
600 PM CST Sat Nov 23 2024

.KEY MESSAGES...

- Fog is possible overnight across portions of the region, with
  visibility potentially dropping to less than 1 mile.

- There is a 10 to 20% chance of light snow over portions of
  south central and northeastern SD into west central MN Sunday
  through Sunday night. Little to no accumulation is expected.

- Much below normal temperatures becoming more likely by the end
  of the upcoming week, with highs in the teens and 20s and lows
  in the single digits to near zero.

&&

.UPDATE...
Issued at 540 PM CST Sat Nov 23 2024

See the updated aviation discussion below for the 00Z TAFS.

&&

.SHORT TERM /THIS EVENING THROUGH SUNDAY NIGHT/...
Issued at 329 PM CST Sat Nov 23 2024

Plenty of mid and high clouds passing overhead, along with areas of
lower stratus across portions of the CWA. Will continue to see
clouds affecting the region through the overnight hours, but the
bigger challenge lies in determining just how expansive the stratus
becomes tonight. Models have had somewhat of a difficult time
handling the lower clouds, so overall confidence isn`t the greatest,
but still anticipate expanding low clouds to some extent,
nonetheless. Models are also indicating fog potential over a good
portion of the CWA, so have inserted mention of this. Maybe a better
bet in the Glacial Lakes region where persistent upslope flow may
aid in fog development. The expected cloud cover also makes low
temperatures a bit tricky tonight. Generally went with NBM for lows,
but could see some locations not getting as cold as its values, due
to the cloud cover.

Next item of interest will be the passing weak wave on Sunday into
Sunday evening. Did end up expanding the slight chance (20%) PoPs
that were across the far eastern CWA. Stretched these chances a bit
further southwest into the southern CWA, given the latest trends in
some of the hi-res output. Looks like a light precip event if any
areas of snow can materialize, with HREF Grand Ensemble probability
of measurable snow generally around 40% or less (mostly less) across
the far southeast CWA, stretching southwest along the FSD CWA
border.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 329 PM CST Sat Nov 23 2024

Main concern for the long term will be our first blast of
cold temperatures as confidence is increasing on arctic air surging
southward over the area for the end of the week into next weekend.
Starting out Monday, the low skirting the Northern Conus/Canada, and
its associated shortwave over the Northern Plains, will continue
eastward through the day with winds turning northwesterly on the
backside of the system. An elongated high pressure system will move
in from the northwest, behind the low, and remain over the area
through Tuesday. Winds aloft will turn more zonal/slight northwest
flow as split flow continues, creating a messy pattern overall. The
high pushes more eastward Wednesday as the pattern aloft will bring
several weak shortwaves/pulses from the northwest with a surface
trough setting up over the Northern Plains. NBM has 15-20% pops for
this time frame with Ptype being snow. No accumulation expected. At
the same time from this northwest flow, a shortwave and its surface
low/front tracks southeast over the Canadian Territories. By 12Z
Thursday, this low is forecasted to be over Manitoba/Ontario border
with a mainly dry cold front having pass through the area. A
stronger high (1036mb!) will move in behind it and remain the
dominant feature through the holiday weekend with overall dry
weather forecasted.

With this high moving in, temps will be about 5 to 15 degrees below
average early next week with the coldest 850mb temps over the
northern and northeastern CWA ranging from -8 to -10C Monday
afternoon and -3 to -7C Tuesday afternoon with 925mb temps -8 to -
10C over this area during this time. Overall highs are forecasted in
the upper teens to upper 20s/30 and lows in the single digits to
lower teens. Jump ahead to the end of the week and next weekend this
next high will bring in even colder temps with a blast of our first
arctic air. Mean GEFS/EC/GEPS indicate 850mb temps Thursday
afternoon/Friday morning range from -10 to -14C with values as low
as -16C over the northeastern CWA by Saturday. Highs for Friday and
Saturday are forecasted to range from around 10 degrees (over the
Coteau) to the low/mid 20s across central SD. Lows are forecasted to
drop well into the single digits to possibility below zero Sunday
morning. This is about 10-20 degrees below average. NBM probability
of lows below zero range from 20-70%, highest over northeastern SD
for the holiday weekend. There is still several degrees difference
between NBM 25-75th percentile range this far out. For fun Sunday
morning (looking to be the coldest morning) ABR could be -6 for the
25th percentile or in the low single digits (75th percentile), so
either way its cold!

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 540 PM CST Sat Nov 23 2024

Terminals KABR,KATY,KPIR,KMBG

There`s been a mixture of cigs late this afternoon across all 4
terminals. KPIR and to a certain extent KMBG have seen MVFR cigs
while KABR/KATY have seen VFR conditions. That will begin to
change a bit later this evening into the overnight for those
eastern 2 terminals as low stratus is expected to build in and
lead to MVFR/IFR cigs. KPIR/KMBG will also see a period of IFR
cigs overnight. Foggy conditions will develop after midnight and
will affect KATY`s terminal with MVFR/IFR vsbys early Sunday
morning through mid morning.

&&

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

$$

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