Watertown, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

699
FXUS63 KABR 030251 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
951 PM CDT Wed Apr 2 2025

.KEY MESSAGES...

- Snowfall coming to an end this evening, with any additional
  accumulations generally around 2 inches or less, mainly in
  grassy areas. Wet roadways may re-freeze overnight and become
  slick by morning.

- There is a 50 to 70 percent chance of light rain and snow
  Friday into early Saturday. Probability of liquid amounts at or
  over 0.10" is 45-65%, highest over south central through
  portions of northeastern South Dakota.

&&

.UPDATE...
Issued at 949 PM CDT Wed Apr 2 2025

Visibilities in falling snow remain under 2 miles from the James
Valley east. Snow is also beginning to stick to some road surfaces
again according to webcam images. Therefore, since conditions are
not improving, decided to extend winter weather headlines again,
ending at 6z.

UPDATE Issued at 648 PM CDT Wed Apr 2 2025

Given the ongoing snow and increasing northwest winds, decided to
extend winter weather headlines through 3z from the James Valley
east. To the west, snow should continue to taper off with no
significant impacts. Across the east, visibilities down to 1 mile
are expected with additional accumulations of around an inch that
may start sticking on roads again after sunset. Wet roads may also
refreeze after dark.

&&

.SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/...
Issued at 307 PM CDT Wed Apr 2 2025

Surface analysis shows the surface low pressure located over
southwest MN, with light to occasional moderate snow continuing to
wrap around across the CWA. Additional accums will be minor (~2" or
less) for most areas, but higher elevations in the Glacial Lakes
region could see those amounts closer to 2 inches. Also, any
additional accumulations will likely be confined to grassy areas
where temps are around 32-34 degrees. Any areas below freezing could
see minor road accumulations. Made several adjustments to headlines
earlier today, and will let current headlines run until the current
expiration time of 00Z for the time being. Evening shift may be able
to start chopping off counties a bit early. Concerning temps
overnight, with a lack of any strong cold air advection, plus
expected cloud cover, do not foresee temperatures dropping off much
more past the mid/upper 20s for most areas even with the fresh snow
cover on the ground.

Broad surface high pressure builds over the region on Thursday.
Looking at light winds for the day, with cool temps remaining in
place, thanks in large part to the snow cover. The Glacial Lakes
region will likely be stuck in the mid/upper 30s, while areas across
central SD with less snow cover will see highs in the 40s and maybe
even close to 50 degrees over areas with little to no snow cover.

Focus will then shift to the next approaching storm system late
Thursday night. Inherited NBM PoPs seemed a bit slow in bringing in
precip after comparing to the latest 12Z deterministic model runs.
Generally did more of an ECAM approach to PoPs from 06Z to 12Z
Friday.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 307 PM CDT Wed Apr 2 2025

Split flow aloft starts out the long term on Friday with a deep
trough that extends southward into Mexico and a weaker trough
extending south/southwestward over the northern CONUS/Canadian
border Friday through Saturday. With the northern wave, its weak
surface low/cold front will pass northwest to southeast over the
CWA. With southwesterly flow aloft to 850mb, models indicate the
convergence of moisture from both of these systems over the area
Friday. There is still a bit of a difference in timing of this
merger as ENS/GEPS has it happening early Friday morning and GEFS
more towards the afternoon. Latest NBM has pops of 40-70% over the
CWA with the highest percent over central SD. Pops will shift east
and southeast with the front through Friday evening with the system
moving out of the area by early Saturday morning. Ptype looks to be
rain on the warm side of the system and snow or a rain/snow mix over
north central SD. However, parts of this area through portions of
northeastern SD may see a bit of freezing rain/drizzle early on, as
ENS soundings do show a slight warm nose with ENS meteograms hinting
at 10% or less of freezing precip. As temps cool towards the
evening, ptype will switch over to snow over the area. NBM 24hr
probability of QPF>0.10", ending Saturday 12Z, is 45-65%, highest
over south central SD. Probability of 1" of snow is 30-40% over
north central SD for same time period. High pressure moves in behind
the system Saturday with a dry cold front sweeping down from the
north late Saturday through early Sunday, associated with a
shortwave plunging southward behind the low over eastern Canada.
Behind this front, another high sinks southward and becomes dominant
for early next week.

Highs for Friday and Saturday will range in the upper 30s and 40s. A
ridge to our west will start to bring in warmer air over central SD
with highs in this area reaching the 50s for Sunday. As this ridge
shifts east, by midweek we could be looking at highs back in the
60s!

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 648 PM CDT Wed Apr 2 2025

Terminals KABR,KATY,KPIR,KMBG

A mix of MVFR and IFR conditions will continue as snow remains
over the region through this evening. Snow will taper off by 6z
with improving vsby, but low cigs will remain until around 20z
Thursday.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Warning until 1 AM CDT Thursday for SDZ006>008-011-
     019>023.

     Winter Weather Advisory until 1 AM CDT Thursday for SDZ018.

MN...Winter Storm Warning until 1 AM CDT Thursday for MNZ039-046.

&&

$$

UPDATE...20
SHORT TERM...TMT
LONG TERM...MMM
AVIATION...20