790
FXUS63 KOAX 111045
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
545 AM CDT Mon Aug 11 2025

.KEY MESSAGES...

- Patchy fog has developed across eastern Nebraska and western
  Iowa, with visibilities dropping below 1 mile at times.

- Scattered showers are possible again on this morning and early
  afternoon, mainly near/south of I-80. Severe storms and
  flooding are unlikely.

- Mainly dry conditions and seasonal temperatures are expected
  through the mid-week.

- Warmth returns by Friday, with increasing chances for heat
  indices to hit 100 degrees.

&&

.DISCUSSION...
Issued at 257 AM CDT Mon Aug 11 2025

Today through Wednesday:

Water vapor imagery this morning features a broad, weakening trough
centered over the Central Plains powering healthy convection across
southern Kansas while the eastern edge of the trough/frontal system
extends northeastward from Missouri into the Great Lakes region.
Drilling down locally, relative high pressure has slid in behind the
frontal system to the south and east and slackened winds. The quiet
wind field has joined a gap in the cloud shield being sent
downstream by the convection down south, increasing the amount of
radiational cooling across the area before cloud cover becomes more
widespread. So far, any lower visibilities have been sporadic at any
one location -- bouncing below and back above 1 mile, across much of
western Iowa and portions of far eastern Nebraska. If fog becomes
more widespread and persistent, a Dense Fog Advisory will be
warranted. Once fog begins to clear around or shortly after sunrise,
it will be joined by an arm of scattered showers and a few rumbles
of thunder beginning to move into far southeastern Nebraska. These
showers and storms should be on the weak side and will decay as they
go north, only mustering light rain and an occasional gust to 30 mph
through mid-morning. The increased cloud cover will help continue
the cooler temperatures, with highs only reach the upper 70s to low
80s this afternoon. An embedded shortwave is also expected to pivot
through the backside of the slowly departing trough late this
afternoon into the early evening, and may force a light shower or
two across northeast Nebraska (10% chance).

For Tuesday and Wednesday, we`ll see that embedded shortwave give a
kick in the pants to the aforementioned larger trough and help sweep
it east of the area. Mid/upper heights will rise and bring
west- northwesterly flow aloft with our soggy pattern running
dry through mid-week. Highs in the 80s alongside a light breeze
will make for a great couple of days to go to the park, dine out
on the patio, or at the very least not strain the A/C too much.
Latest runs of the ensemble guidance does show a compact
shortwave moving across South Dakota Wednesday afternoon,
putting us not too far off from some low- end severe threat, but
the best chances are still off to the north.

Thursday and Beyond:

By the latter half of the work week, we begin to see the upper
pattern begin to shift, transitioning a low-amplitude ridge from the
Desert Southwest towards the Lower Mississippi Valley. As it passes
to the south and eventually settles to the southeast of the forecast
area, we`ll see high temperatures trend towards the 90s before
arriving area-wide Friday, lasting into early next. With the
forecast area being on the far northern end of the ridge to the
south, we`ll find a stationary front that will set up shop across
southern South Dakota, helping to provide some forcing for ascent in
addition to passing mid-level shortwave impulses that will drive
nearly daily chances for rain Friday onward. A conservative forecast
is currently in place for dewpoints during this period, and heat
indices of 100+ look likely for most of the area late this week --
especially Friday afternoon. If surface moisture  trends upwards, we
would see the need for another Heat Advisory that would feel just a
tiny bit warmer after such a pleasant early to mid-week.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 541 AM CDT Mon Aug 11 2025

Fog has developed primarily along the Missouri River into
western Iowa this morning, tanking visibility values into the
LIFR range and near airport minimums at KOMA this morning while
KOFK has largely stayed MVFR and KLNK has stayed VFR. Short-term
models indicate that visibility values will stay sporadic in
northeast Nebraska, while KOMA will have the best shot at
seeing more continuous fog, that should begin improving around
12-13z. By 14z MVFR to largely VFR conditions should resume, and
chances for rain and a few rumbles of thunder will linger near
the NE/KS border, but should not arrive at KLNK, leaving light
winds out of the south through the day.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.

&&

$$

DISCUSSION...Petersen
AVIATION...Petersen