Janesville South Dakota Weather Forecast Discussion

844
FXUS63 KFSD 091655
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1155 AM CDT Thu Oct 9 2025
.KEY MESSAGES...
- Near to above normal temperatures will persist into early next week.
- The next chance for rain will not arrive until Saturday
  evening and Sunday. A this time, chances for rain remain
  between 30-60% though the highest probabilities lie north and
  east of the area.
- Additional chances for rain are possible into the middle of
  next week though details are very uncertain.
&&
.DISCUSSION...
Issued at 327 AM CDT Thu Oct 9 2025
Quiet conditions begin the day today along with mid level clouds
blanketing locations generally along and east of the James River. A
few sprinkles are possible beneath the stratus but low level dry air
should prevent the majority of the sprinkles from reaching the
surface. Winds will strengthen this morning as mixing increases
after sunrise. This will result in another breezy day with southerly
winds gusting up to 20-35 mph. The mid level clouds will drift
slowly eastwards, covering most locations along and east of I-29.
This will make for cooler temperatures in the low to mid 70s east of
I-29 and warmer temperatures up to the mid to upper 70s west of the
interstate. Could see highs reach 80F in this area as well. A cold
front will begin to push into the forecast area during the late
afternoon hours. The strongest cold advection with the front will
come in late tonight and be place north and east of the area. This
will result in weakening winds behind the front. Wind won`t go
completely calm overnight but will be much lighter and turn out of
the northwest. Low temperatures will fall to 40s and 50s. There
could be some fog south of I-90 late tonight but confidence is too
low to include in this forecast package at this time.
Friday will be a quiet day as surface ridging slides through the
Northern Plains. Winds will be light while temperatures remain near
to above average in the 60s to mid 70s. This will make Friday a
great day for outdoor activities! Overnight lows will be a bit
cooler, falling to the upper 30s and 40s across the area.
Medium range guidance remains in agreement in a stronger upper level
wave beginning to eject out of the Rockies and into the Plains
states during the weekend. Think the daylight hours will remain dry
on Saturday due to drier air in the low levels. With large scale
ascent pivoting over the Northern Plains, surface pressure will
fall, tightening the surface pressure gradient. This will lead to
breezy southeast winds across the area along with high temperatures
remaining near seasonable in the 60s thanks to mid and high level
clouds blanketing most of the area ahead of the incoming wave. The
exit region of the jet tied to this wave will encroach on the
forecast area Saturday evening, strengthening low level warm air
advection (WAA) and bringing chances for rain back to the area. The
ensembles support this as they show a broad 30-60% chance for
rainfall totals to exceed a tenth of an inch of rain Saturday
evening and night. However, they also show the highest probabilities
lying across eastern North Dakota and northwest Minnesota. Similar
probabilities for rain persist through Sunday as the main wave fully
ejects into the Northern Plains. Persistent WAA will result in
warmer temperatures for the afternoon hours on Sunday with highs
warming to the 70s to low 80s. A stronger cold front tied to this
wave will push through the Northern Plains Sunday evening and night.
A strong shot of cold air advection (CAA) behind the cold front
could lead to stronger winds during this period of time. As of now,
confidence is not high enough to deviate from the NBM but will
continue to watch over the next few days.
The upper level jet will continue to sit over a large part of the
country on Monday with the jet spanning from southern California all
the way to the Great Lakes. Despite the jet, Monday will be a dry
day as surface high pressure slides through the area along with near
seasonable highs in the 60s. This will change heading into Tuesday
as heights begin to fall aloft. Tuesday during the day looks to be
dry with highs in the 60s but low level WAA will strengthen Tuesday
evening and night. Moisture return does not look all that impressive
during this period of time though. Thus, the ensembles only show a
mere 10-30% chance for rainfall to exceed a tenth of an inch of
rain.
There could be additional chances for rain next Wednesday and though
confidence in this next potential is low due to medium range
guidance showing increasing variance in the upper level pattern. The
ensembles are in general agreement in upper level ridging remaining
over the plains during this time, though they do also show the
previously mentioned upper jet draped atop the ridge over the
Plains. Despite the general agreement, the ensemble still show
varying low probabilities between 10-30% for exceeding a tenth of an
inch of rain. Latest trends have been building the ridge more aloft
and retrograding it westward. This is a more commonly observed trend
regarding these ridges so do think that the ensembles are on the
right track. Will leave the NBM PoPs in place for now. Otherwise
seasonable temperatures are favored for the middle of next week.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1151 AM CDT Thu Oct 9 2025
A cold front will sag south into the area tonight but is not
expected to spark any precipitation. Conditions should be
mainly VFR through the period. Some hints that near and south
of this front, mainly far southern SD, northeast NE and
northwest IA, may see some lower end MVFR ceilings and patchy
fog as moisture below the inversion drifts northeast during
this time. Some of this was seen earlier this morning in central
parts of NE. The incoming front should scour out any of the sub
VFR conditions from about 12-15z Friday.
Otherwise southerly winds will gust around 30 to 35 mph at times
today before weakening around sunset and transitioning to a more
northerly direction through the night.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...Meyers
AVIATION...08

NWS FSD Office Area Forecast Discussion