Watertown, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

599
FXUS63 KABR 061133 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
633 AM CDT Sun Oct 6 2024

.KEY MESSAGES...

- Northwest winds will remain gusty over far northeastern SD into
west central MN this morning with gusts of 30 to 40 mph.
Winds will diminish through the day with light winds expected
tonight.

- Dry and mild conditions through next week. Temperatures peak
around Thursday with highs in the mid 80s or about 15 to 25 degrees
above normal.

&&

.UPDATE...
Issued at 627 AM CDT Sun Oct 6 2024

See below for an aviation forecast discussion for the 12Z TAFs.

&&

.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 324 AM CDT Sun Oct 6 2024

As of 3am the cold front continues its track southeast through the
state with temperatures ranging in the 50s (thanks to mixing keeping
it milder) and winds out of the northwest. Highest gusts have been
over northeastern SD ranging from 25 to 45 mph. ABR had a peak gust
of 42mph at 1:46am and Sisseton gusted to 46 mph shortly before 2am.
HREF along with GFS/EC ensembles are in agreement with the stacked
low continuing to push east and will be centered over Ontario at
12Z. Behind the system a ridge is positioned over the western CONUS,
leaving the Northern Plains in northwest flow aloft. This ridge will
become more amplified as it slightly pushes east. By Monday, a weak
shortwave, riding up and around the high over the Southwest US, will
position itself over WY/NE and southwestern SD which will turn mid
level winds more zonal across central and western SD with northwest
flow continuing eastward. Down at the surface, this secondary cold
front will continue to push southeast with the front exiting the CWA
by early this morning as a high pressure system moves in behind it.
This high will be centered over the Northern Plains this afternoon
into tonight, pushing southeast Monday. Latest HRRR Smoke shows
plumes of smoke aloft moving in from the west/southwest starting
early Monday, so incorporated it into the sky grid.

On the backside of this low, HREF indicates by 12Z, 700mb winds will
continue between 40-50kts and 850mb winds 30-40kts, with the highest
winds over northeastern SD/western MN. This is where we are seeing
the steepest gradients with weak CAA and 6-7mb/6hrs pressure rises.
Soundings show winds from bottom to top of the mixing layer ranging
from 15-25kts over this area through the afternoon before
decreasing. Latest HREF prob>35 mph is 40-100%, highest over the
Coteau, at 12Z. Values remain high over the Coteau with the
percentages really dropping off late morning. However, gusts up to
30 mph are still possible through the midday. As this system
continues east and the high moves in (and influence from the ridge),
winds will decrease to 20-30kts at 700mb and 10-20kts at 850mb over
this area by this evening along with ongoing diminishing surface
winds. Otherwise, calm to light winds expected tonight and Monday.

With the colder air, 850mb temps this afternoon will range from +5
to +10C with 925mb temps overnight ranging from 11 to 14C. Models
are in good consistency with highs for today ranging in the 60s
(around average), coolest at the higher elevations. With the clear
skies tonight, light winds, and longer nights, I did incorporate NBM
25th into the blend which bring lows down into mid to upper 30s to
lower 40s. Running the frost tool, it does show the potential for
frost in the James River Valley and eastward. Highs for Monday will
rebound into the upper 60s to the mid 70s(above average) as winds at
850mb turn more south/southwesterly ushering in warmer air.

&&

.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 324 AM CDT Sun Oct 6 2024

Little in the way of change in the extended forecast, compared to 24
hours ago. Upper level ridging will eventually flatten out as some
shortwave energy tries to push east across the middle of the country
by Saturday/Sunday. So, very limited precipitation chances during
the period. At the surface, high pressure settles in east over the
region, allowing for a rather weak return flow pressure gradient to
develop. Really kind of a washed out pressure field, so not a whole
lot in the way of wind is forecast, which keeps the lid on potential
hazardous fire weather conditions, as the previous shift mentioned,
because dry and warm air remains over the region. Models do generate
a cold frontal passage heading into Thursday night, with more
surface high pressure building in behind it. Still seeing the
temperature guidance trending warmer through Thursday, before a
potential drop off for Friday and on into the weekend behind said
cold frontal passage. There is also markedly more spread in the 25-
75th percentiles of both high and low temperatures Friday and
beyond. Something for future shifts to scrutinize.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 627 AM CDT Sun Oct 6 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through the TAF period. Northwest winds
will diminish through the day becoming light and variable this
evening.

&&

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

$$

UPDATE...Dorn
SHORT TERM...MMM
LONG TERM...Dorn
AVIATION...Dorn