Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 180208 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
908 PM CDT Sun Mar 17 2024

.KEY MESSAGES...

- Warmer Monday with high temperatures in the 40-50s east river
  and 60s west river. Winds will increase out of the west in the
  afternoon. Gusty winds combined with afternoon humidity of 15
  to 25 percent will result in high to very high fire danger.

- Above normal temperatures (highs in the 40-50s) continue
  Tuesday. Temperatures then drop below normal for Wednesday
  though Saturday.

- A quick moving system will bring the chance for accumulating
  snowfall on Thursday. For most of the region, models are
  showing an inch or less of accumulation. However, for northeast
  South Dakota and west central Minnesota, there is currently a
  40-60% chance of exceeding 2 inches.

&&

.UPDATE...
Issued at 907 PM CDT Sun Mar 17 2024

Current forecast is on track, therefore no changes made at this
time.

&&

.SHORT TERM /THIS EVENING THROUGH MONDAY NIGHT/...
Issued at 232 PM CDT Sun Mar 17 2024

Surface high pressure will gradually settle into the region tonight,
allowing the gusty northerly winds to taper off this evening.
Satellite trends and HREF cloud cover progs also show the continued
erosion of the stratus deck through this evening. There may still be
flurries east of the James River Valley through 00Z, but should end
shortly thereafter.

High pressure will be short lived. A weak upper level shortwave will
traverse northwest flow aloft, with a resultant surface trough
developing Monday. Surface winds will return from the west southwest
and warm air advection will occur ahead of the trough. With the warm
dry air, high to very high fire danger will be in place. Variables
don`t quite come together perfectly to meet red flag criteria. HREF
probabilities of wind gusts greater than 25 mph are 70-100% across
north central and northeast South Dakota, but the probability of RH
dropping below 20% in this area is less than 15%. Meanwhile, south
central South Dakota has a 60-70% chance of RH dropping below 20%
but less than 15% chance of wind gusts over 25 mph. Of course, lack
of green up and dry fuels remain a concern. However, due to the
marginal criteria, will let the RFD highlight the message without a
formal headline right now. The other concern will be downslope winds
in the lee of the Sisseton Hills. WAA and a persistent inversion
combined with southwest to west winds will allow for a decent
downslope setup. Gusts in excess of 40 mph are expected.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 232 PM CDT Sun Mar 17 2024

Northwest flow continues for the start on the long term on Tuesday
as Clusters agree on a +PNA pattern setup. By Wednesday, this ridge
moves over the Rockies, becoming a little less amplified as a
positive tilted shortwave starts to dig into it, originating from
Alaska/western Canada coast, with the ensembles fairly in agreement
on the intensity and position of this ridge and shortwave. Through
Wednesday into Thursday, this northern shortwave merges with another
wave over the Pacific as a low continues to stay fairly stationary
over Canada and trough over the northeast. We start to see
differences between the ensembles on intensity/placement of this
trough out west, especially the further out in time you go, and how
amplified or flattened the ridge will be (from this low over
Canada). Overall, it looks like a -PNA setup for the weekend.

Dry conditons Tuesday and Wednesday before some mid level
energy/850mb low moves over the Northern Plains on Thursday,
downwind of the ridge. Clusters differ on where the QPF will end up.
For example, Cluster 1 (made up of 50% EC,23% GEFS,25% CMC) keeps
the QPF over ND/MN. Cluster 2 (mostly CMC/EC) has the QPF more south
over much of the CWA and Clusters 3/4 keeps the QPF clipping the
northern and northeastern CWA. EC meteograms has 40% chance of snow
at KABR/KATY, 30% KMBG, and less than 10% for KPIR with precip
continuing into Friday so seems to follow more Clusters 3/4 for now.
So confidence remains low at this time on exact setup. Next weekend
could bring the possibility of more QPF (snow) from this mid level
energy/sfc low as EC meteograms at all sites having a broad range of
30-50% chance of pops for now.

For Thursday, WPC has a 10-70% chance (highest over northeastern
SD/western MN) of 24hr snow>1" and 10-40% chance of 2 inches or
over,highest over northeastern SD, and 20% or less of 4" or more.
The individual ensembles have this similar outcome with the highest
chance of heavier snow along ND/SD border across into west central
MN. Glancing at WPC Plumes, ABR`s mean snow looks to be right around
an inch with equal spread above and below this. Latest NBM has 15-
20% pops moving in over northwestern CWA Wed night and overspreading
much of the CWA into Thursday (besides south central SD for now)
with up to 50-75% across ND/SD border into west central MN.

Tuesday will be our last mild day in the 40s/50s before temps cool
down into the 30s/40s by end of the week into the weekend as CPC 6-
10 day outlook runs 50-70% below average in temps with this -PNA
setup.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 623 PM CDT Sun Mar 17 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail across the area tonight and through
the day Monday. Northerly winds in the 15 to 30 knot range will
become light overnight, then will shift to a southwesterly
direction and increase back into the 15 to 30 knot range again on
Monday.


&&

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

$$

UPDATE...Parkin
SHORT TERM...Serr
LONG TERM...MMM
AVIATION...Parkin


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