Le Mars, Iowa Weather Forecast Discussion

091
FXUS63 KFSD 290819
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
319 AM CDT Mon Sep 29 2025
.KEY MESSAGES...
- Well above normal temperatures continue through the upcoming
  week. A record or two may fall today and potentially Thursday
  and Friday.
- Dry conditions are expected through most of the work week. A
  few daybreak sprinkles/showers are possible through the first
  half of the week, but chances remain < 20%.
- Dry and breezy afternoon conditions over the next week could
  lead to low end fire weather concerns as fire fuels continue
  to dry out.
- Next reasonable risk for widespread rain arrives by and into
  next weekend, with a cool down in temperatures.
&&
.DISCUSSION...
Issued at 318 AM CDT Mon Sep 29 2025
NOW THROUGH TONIGHT: A warmer start to the day with temperatures
this morning in the 50s to mid 60s. Mid level clouds are beginning
to increase across south central SD in response to the strengthening
LLJ and a weak wave moving through. Can`t rule out some sprinkles
with some returns on radar at the time of this discussion, but dry
sub cloud layer should keep most dry through daybreak.
Warmer today with a boundary lifting north through the area, as well
as mixing into warmer air aloft. Highs in the mid 80s to lower 90s
which is roughly 15-20 degrees above average. A couple of sites may
approach records for highs - Sioux Falls (90 in 1897) and Mitchell
(92 in 2024) will both be within a couple of degrees of record.
These warm temperatures along with breezy southerly winds may lead
to some elevated fire danger, although humidity values above
critical thresholds should keep conditions localized. Strongest
winds are expected across south central SD with gusts around 25
mph. Lows tonight fall into the upper 50s and lower 60s.
May see some hazy skies with wildfire smoke in the area. Not
expecting much in the way of surface impacts, but could some
reductions in air quality. Otherwise, mid and high clouds will be a
bit more prevalent today.
TUESDAY-THURSDAY: A couple of waves/vorticity lobes move north
through the southwesterly flow aloft through mid week as high
pressure aloft stagnates over the Midwest. CAMs are more bullish
with shower/sprinkle chances on Tuesday; however, dry soundings lead
to lower confidence in occurrence. May see some lower end chances
during the overnight and early morning hours Wednesday and Thursday
with the LLJ and the timing of the waves. Despite an increase in
surface dew points with more southeasterly flow mid week, there
remains a lack of a deep moisture layer coupled with a dry sub cloud
layer. Will keep precip chances on the lower (< 15%) side for now.
Temperatures remain above normal, with a slightly cooler day Tuesday
due to cooler temperatures aloft. Highs in the 80s and lows in the
upper 50s to mid 60s. Temperatures may stay elevated enough during
the overnight hours to approach a couple of record warm low
temperatures. Southerly surface winds remain breezy, especially
during peak mixing, with gusts around 25-30 mph. The increase in dew
points should help offset the breezy conditions, very warm
temperatures, and drying fuels to limit widespread fire concerns.
That said, some lower end and localized concerns are possible.
FRIDAY-SUNDAY: Mid/upper level high pressure flattens toward the end
of the week with troughing over the western CONUS moving east
through the weekend. Surface low moves east during this time as
well. Precipitation chances may return as early as Friday, but
better chances look to be Saturday onward with a stronger low
pressure and mid/upper level wave. That said, guidance is still
quite varied on the details. Ensemble probabilities are trending
upward, toward 50%, but uncertainty remains.
As for temperatures, well above average temperatures continue through
at least Friday as we remain ahead of the cold front. Near records
are possible for both high temperatures and warm low temperatures
with highs in the 80s to near 90 and lows in the 60s. Cooler, but
still above average, conditions move in by Sunday with highs in the
70s and lows in the 50s.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1040 PM CDT Sun Sep 28 2025
VFR conditions expected through the TAF period. There is a low
probability (less than 15%) for sprinkles over central SD toward
Monday morning, though if these were to occur they would remain west
of KHON. Strongest winds will reside west of Interstate 29
through the period, with gusts around 20 kts over that area on
Monday afternoon into early evening.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...SG
AVIATION...JM

NWS FSD Office Area Forecast Discussion