Watertown, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

716
FXUS63 KABR 040526 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1126 PM CST Tue Dec 3 2024

.KEY MESSAGES...

- Potent cold front moves through Wednesday morning, bringing
  strong northwest winds with gusts 40 to 55 mph, potential snow
  showers, and falling temperatures through the day. Drifting
  snow may cause icy roads. Patchy blowing snow could cause some
  reductions in visibility.

- Milder temperatures for late in the week and into the weekend with
  highs/lows forecast to be some 10 to 20 degrees above normal.

&&

.UPDATE...
Issued at 1122 PM CST Tue Dec 3 2024

See below for an aviation forecast discussion for the 06Z TAFs.

UPDATE Issued at 941 PM CST Tue Dec 3 2024

The latest available guidance supports adding central/south
central South Dakota to the wind advisory. Starting it 3 hours
later than the rest of the forecast area. Also, starting to see
evidence in the latest guidance that during the time of fropa,
stratus (super-cooled liquid droplet) clouds will be rapidly
shifting southward with the fropa and rapidly cooling to the DGZ.
Until it reaches the DGZ, BUFKIT soundings suggest 1KM or nearly
1KM saturation may happen (with some omega within the stratus)
with drizzle/freezing drizzle for an hour or two depending on
surface temperature could happen. Snow chances briefly chase that
southward out of the CWA when the stratus clouds reach DGZ
temperature and the droplets activate ice (snowflakes). Forecast
has been updated to reflect all this. Plus, that blowing snow
potential still exists (temperatures did not reach freezing or
warmer up on the Coteau earlier today) up on the Coteau over into
west central Minnesota from late Wednesday morning through early
Wednesday evening when temperatures tumble into the upper single
digits to upper teens and sustained winds, post-frontal, ramp up
to 25 to 30 knots. Updates are out.

UPDATE Issued at 528 PM CST Tue Dec 3 2024

See below for an aviation forecast discussion for the 00Z TAFs.

&&

.SHORT TERM /THIS EVENING THROUGH WEDNESDAY NIGHT/...
Issued at 321 PM CST Tue Dec 3 2024

Warmer temperatures have briefly returned this afternoon with
readings ranging from the upper 20s along the Coteau to the lower
50s along and west of the Missouri River. However, an arctic front
barrels in late tonight into Wednesday morning with H85 temps
falling from +8C into the negative teens Celsius by late afternoon.
Temperatures at the sfc will fall through the day, accordingly.

The pressure gradient tightens ahead of the approaching high with a
10 to 12 mb spread across the state. This gradient plus the thermal
packing in the strong caa will cause northwest winds to gust to 45
mph. One thing to watch will be the very strong winds aloft with 80
kts at 700 mb by afternoon and even 50 kts at 850 mb on a few model
iterations. Wind gusts could easily overachieve from current probs
and forecasts. Forcing outside of the caa is minimal with only some
weak shortwave energy sliding through northeast SD and west central
MN in the upper trough. That`s where chances for some light snow
accumulations of up to half an inch are focused Wed morning.
Moisture in the DGZ will be the real question, but arctic fronts
tend to squeeze out some snow showers even with limited moisture
availability. The winds, combined with falling snow or even the snow
on the ground across the Coteau, will produce some drifting or
blowing snow. The question is how much the snow on the ground will
blow around. Will need to watch the Coteau and possibly the Leola
Hills for a winter weather advisory if snow lofts more than
expected. For now, issued a wind advisory for most of the cwa. Would
not be surprised if the advisory is expanded during the overnight
depending on how wind observations pan out upstream.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 321 PM CST Tue Dec 3 2024

Thursday morning starts the long term with upper level flow from the
northwest. This is the back (upwind) side of the trough that will be
moving out of the area through the day. However, we will remain in
northwesterly flow as an upper level ridge remains in place to our
west. At the surface, we are under high pressure Thursday and a warm
front moves through from west to east on Friday. Sunday morning,
this upper level ridge moves into the region and by Sunday
afternoon, the axis is over the forecast area. Monday, an upper
level low starts to move southeast out of Canada into the Dakotas.
The surface level low will move through the area, along with a cold
front, during the day Sunday. There is potential for a second cold
front to move north to south across the region Monday afternoon into
Tuesday.

Behind the Sunday cold front, there is a 15 to 25% chance for some
light snow along the ND/SD border. Accumulations have about a 30%
chance of exceeding a tenth of an inch. Some light snow with about
the same accumulation chances will be possible with that potential
second cold front.

As for temperatures, we will be on a bit of a ride. Thursday is
expected to be the coldest of the period as some pretty strong CAA
moves in overnight Wednesday. The weekend is looking to be rather
nice with highs just above freezing in eastern SD to as warm as low
50s west river. The cold front Sunday into Monday will bring some
colder air back to the forecast area and cool temperatures back to
around normal. Winds don`t look to be anything out of the ordinary
until potentially Monday afternoon when west river counties have a
50-70% chance of gusts higher than 35 mph as the cold front moves
through.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1122 PM CST Tue Dec 3 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions right now, but not for much longer. Between 06Z
and 18Z, sub-VFR cigs approaching from the north overspread all
four terminals. An arctic frontal passage could yield some
scattered snow showers or patchy, short-lived, very light
freezing drizzle. Strong winds coincide with the fropa and persist
behind it well into the day on Wednesday. There`s lower
confidence in any reduced vsby in snow showers and blowing snow so
haven`t introduced a notably reduced visby in falling/blowing
snow yet.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 3 AM CST /2 AM MST/ to 6 PM CST /5 PM MST/
     Wednesday for SDZ003>011-015>023.

     Wind Advisory from 6 AM CST /5 AM MST/ to 6 PM CST /5 PM MST/
     Wednesday for SDZ033>037-045-048-051.

MN...Wind Advisory from 3 AM to 6 PM CST Wednesday for MNZ039-046.

&&

$$

UPDATE...Dorn
SHORT TERM...Wise
LONG TERM...KK
AVIATION...Dorn