356
FXUS63 KABR 211122
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
522 AM CST Sat Dec 21 2024

.KEY MESSAGES...

- There is a 20% chance of a light wintry mix of precipitation,
including rain, freezing rain, or snow over north central SD Sunday
afternoon and across northeastern SD into west central MN Sunday
night.

- Temperatures will run around 5 to 15 degrees above normal Sunday
through Saturday.

&&

.UPDATE...
Issued at 518 AM CST Sat Dec 21 2024

Aviation discussion has been updated in accordance with the 12Z
TAF issuance.

&&

.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 249 AM CST Sat Dec 21 2024

High pressure center to the northeast brings low-level warm air
advection to the area and helps keep temperatures today normal to
even above normal today. Partly to mostly cloudy skies will hang
around over northeastern South Dakota/western Minnesota today, but
more clearing is expected over the central part of the state,
helping boost high temperatures another couple of degrees. 20s to
30s are expected over the northeastern part of the forecast area,
while we may see up to the low 40s over central South Dakota this
afternoon. Predominantly mid to high cloud cover Saturday night into
Sunday will allow for partial radiational cooling pushing overnight
lows into the teens to low 20s.

Attention then turns to the next low pressure center impacting the
area on Sunday evening. Some spotty precipitation is expected to
fall over the northernmost parts of the forecast area, but it
remains unclear how that will play out over the course of the day.
While the system is still on the edge of hi-res range, there is
little consensus as of yet. Precipitation is expected to be spotty
with little QPF to speak of. Still, recent systems have tended to
overachieve, so there is potential for a few hundredths of liquid
equivalent to fall. Current probability of measurable precipitation
from the HREF maxes out over north central South Dakota at roughly
40% through 0Z Monday. Soundings show a layer of dry air aloft,
meaning that precipitation will form below the DGZ as liquid and
that freezing rain will be the primary precipitation type. Have
opted to go with slight chance Pops for the time being, but as the
hi-res models come into focus through today that could easily be
increased.

&&

.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 249 AM CST Sat Dec 21 2024

Other than the initial light wintry mix of precipitation over mainly
northeastern SD and west central MN Sunday night, the remainder of
the forecast period looks dry. Our above normal temperature trend
will continue too, well into the 6-10 and 8-14 day period as noted
by the CPC outlooks with a 60-90% chance of above normal
temperatures. Normal highs this time of year range are in the 20s,
with some values near 30 early in the period over central SD. Other
than temperatures Sunday night through Monday night, where the NBM
25th and 75th percentiles are 8-10 degrees apart, there is pretty
solid consistency in the temperature forecast. This is leading us to
higher confidence in the temperatures and their general steady to
upward trend through at least Saturday.

Starting at 00Z Monday the quickly moving 500mb low will be over
western to central ND into north central SD. There is some
variability in the track, with the operational GFS and ECMWF tracking
the low farther south and across northeastern SD by 06Z Monday while
the Canadian staying in ND. The NAM is in between these solutions.
The low will shift over MN by 12Z Monday. So, there is still some
variability in the light precipitation that will result. With
temperatures hovering near freezing, precipitation types remain a
concern. Have brought the potential for a 20% chance of precipitation
farther south once again. As with the system Friday, forecast models
tend to be less robust than needed with these quick moving features.
We will continue to fine tune the temperatures/precipitation type.
At this time we do have light icing (freezing rain) near the
ND/SD/MN borders. The potential exists that this may also sink
farther south, so stay tuned to further forecasts.

Ridging will return at 500mb Monday afternoon with another wave
moving through Monday night, suppressing the ridge. Overall though,
despite small waves moving through our area, no significant weather
is expected. The main trail of storms will stay well to our south as
a series of lows move across the Southern Plains.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 518 AM CST Sat Dec 21 2024

Terminals KABR,KATY,KPIR,KMBG

|Cloud deck currently over North Dakota is moving south east down
into northeastern South Dakota this morning. VFR conditions are
expected to continue, at KABR and KATY but observations on are
limited upstream of KABR due to the direction of flow. MVFR ceilings
therefore cannot be ruled out, but have elected to leave them out of
the TAFs for now. High clouds from the west move in this morning as
well, and are expected to persist through the rest of the TAF
period, supporting VFR conditions. Winds out of the south will range
from 10 to 15 knots, with gusts to 20 at most this afternoon over
eastern South Dakota. Winds back slightly to the southeast near the
end of the TAF period as the next low pressure center tracks south
overtop western South Dakota.

&&

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

$$

UPDATE...BC
SHORT TERM...BC
LONG TERM...KF
AVIATION...BC