South Sioux City, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

629
FXUS63 KFSD 100844
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
344 AM CDT Sun Aug 10 2025

.KEY MESSAGES...

- A few scattered showers with an occasional stroke of
  lightning will move through areas south of the Highway-18
  corridor in northwestern IA this morning.

- Patchy areas of locally dense fog will continue across the
  area through mid-morning. With visibilities of 1 mile or less
  possible at times, be prepared for rapid changes in visibility
  over short distances.

- Wildfire smoke returns to the area this afternoon. While most
  of this should stay aloft, slight reductions in air quality
  and visibility at the surface will be possible.

- Near to above normal temperatures will continue into the new
  week with daily highs in the low to upper 80s and low 90s
  expected.

&&

.DISCUSSION...
Issued at 342 AM CDT Sun Aug 10 2025

TODAY & TONIGHT: A seasonable day ahead! Taking a look across the
area, our attention continue to be on the developing areas of fog
across northwestern IA and the developing Mesoscale Convective System
(MCS) across eastern NE and western IA. Starting with the fog,
lingering low level moisture and lighter surface winds have led to
some patchy fog developing this morning. While not expected to be
widespread, locally dense patches east of I-29 could lead to
visibilities of a mile or less at times this morning. Nonetheless,
expect most of the fog to gradually erode as diurnal heating returns
after daybreak. With this in mind, make sure to drive with care if
you have plans in town this morning. Shifting gears to the ongoing
MCS, current radar imagery has this system tracking to the east-
northeast following the 300-800 mb mean wind this morning. Given
that the better instability gradient remain well to our southeast
and its parent wave is tracking the same way, expecting the stronger
convection to follow suit.

Nonetheless, can`t rule out some light to moderate showers with an
occasion stroke of lightning at times on the northern fringes of the
system. With pockets of drier air according to soundings, any
rainfall accumulations should be on the lighter end with up to 0.25"
of an inch possible across portions of northwestern IA. From here,
should see things clear out of our area by mid-morning (10 am). As
quieter conditions return by late morning, should see our
temperatures gradually increase into the upper 70s to low 80s.
Lastly, more Canadian wildfire smoke will move into the region
starting this afternoon. While most of this should stay aloft,
slight deterioration`s in air quality and visibility will be
possible at the surface through tonight. With this in mind, make
sure to monitor your local air quality if you have any outdoor
activities planned especially if you`re apart of a sensitive group.

MONDAY-WEDNESDAY: Looking into the new week, a troughy pattern
continues aloft as a series of waves swings through the northern and
central plains. While most of our area should stay dry through
midweek, can`t completely rule out a few scattered showers by
Tuesday afternoon as a weak cold front swings through the area.
However, with the already limited instability (<1000 J/kg) displaced
from the better shear; no organized convection is expected.
Otherwise, expect temperatures to hover near our seasonal normals
through the period with daily highs in the low to upper 80s
expected.

THURSDAY ONWARDS: Heading into the extended period, quasi-zonal flow
returns aloft as weak mid-level ridging moves across the northern
plains. As a surface warm front gradually lifts through our area,
mid-level warm air advection (WAA) will strengthen between Thursday
and Friday. This along with southerly surface winds should lead to a
gradual increase in temperatures with daily highs mainly in the mid
80s to low 90s on both days. Could see some smaller precipitation
chances (<30%) return by Thursday as a weak wave moves across the
northern portions of SD. However, accumulations will likely be kept
to a minimum.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1030 PM CDT Sat Aug 9 2025

Although most of the area will be dry for tonight, some hi-res
guidance continues to suggest a possibility of showers and
storms creeping into the lower MO River Valley into northwest IA
late tonight - though at this time probabilities look low
(20%-30%). Otherwise, areas of fog will be possible late
tonight into Sunday morning, with the higher probabilities
(40-60%) residing through northwest IA into portions of
southwest MN. Winds will be light through the TAF period.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...05
AVIATION...JM