031
FXUS63 KOAX 020437
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1137 PM CDT Fri Aug 1 2025

.KEY MESSAGES...

- Smoke impacts continue this afternoon into Saturday. The
  Nebraska Department of Environment and Energy has extended
  their Air Quality Alert until 5 pm Saturday.

- Shower and storm chances return early Saturday morning (15-30%
  chance) with the highest chances across northeast Nebraska.

- More showers and storms redevelop late Saturday night into
  early Sunday (30-50%), and again Sunday night into Monday
  (20-30% chance)

- Temperatures cool to the low 70s and 80s for this weekend
  before warming up into the low 90s by Thursday. Nighttime
  chances (15-30%) for showers and storms are expected Tuesday
  through Thursday.

&&

.DISCUSSION...
Issued at 316 PM CDT Fri Aug 1 2025

.SHORT TERM.../Today through Saturday Night/

Generally quiet conditions are observed across OAX this afternoon.
This is largely driven by a 1029 mb sfc high, with 19z RAP objective
analysis showing the sfc high centered over eastern Minnesota into
Wisconsin. Aloft at H5, west to northwesterly flow has resulted in
wildfire smoke from eastern Manitoba traveling southeastward into
much of the Northern Plains. Coupled with large scale subsidence
triggered by the sfc high, much of this smoke has made it to the sfc
as 19z METARs are reporting visibilities anywhere from 4 to 7 statue
miles. The smoke has resulted in moderate to unhealthy air quality
across much of the forecast area. This has prompted the Nebraska
Department of Environment and Energy to extend the Air Quality
Alert, which will remain in effect until 5 pm Saturday. The Iowa DNR
has also extended their Air Quality Alert for our western Iowa
counties until 8 am Sunday.

Alongside the smoke, some mid to high level clouds have filtered in
from the west, while low level cumulus tracks to the west following
the motion of the low level high. Weak warm air advection observed
at H7 has led to some weak showers entering our western counties.
This activity is most likely not reaching the ground, with BUFKIT
soundings showing a pocket of dry air between H7 and H8. Have
introduced some low end 15% PoPs across mainly our far western and
southwestern counties through at least 21z and dissipating
thereafter. Given the cloudiness, have also decided to lower highs
slightly from NBM guidance for today, with most areas seeing highs
reach the low to mid 70s. Lows tonight will be in the mid 50s to low
60s with light winds from the southeast.

By early Saturday morning, a shortwave ejecting from eastern Wyoming
will traverse the South Dakota/Nebraska border. Lift will overspread
portions of central and northeast Nebraska, and with H8 moisture
transport pointing into the area, could see a few scattered showers
and storms develop. MUCAPE seems rather minimal at around 500 J/kg,
and with poor shear, not really expecting to see strong storms with
this activity. PoPs peak at around 30% across far northeast Nebraska
from around 9z to 13z, with values tapering off during the late
morning. Otherwise, will see smokey skies with highs reaching the
mid to upper 70s.

By Saturday evening, another shortwave trof will eject from out
west. H8 analysis shows a baroclinic zone developing across much of
central Nebraska. The baroclinic zone in tandem with the shortwave
vort max will help generate lift for scattered showers and storms,
which will overspread the area from west to east. NBM guidance
currently has low end 15% PoPs across our far northwest counties
Saturday evening, but most recent CAM guidance suggests PoPs
arriving at our doorstep early Sunday morning. Lows Saturday night
will be in the upper 50s to low 60s.

.LONG TERM.../Sunday through Thursday/

PoPs (30-50%) will be ongoing early Sunday morning across much of
eastern Nebraska. Instability looks a bit more plentiful with this
round of convection, and with marginal shear at around 30 kts, could
see a strong storm or two, but model guidance seems to suggest shear
decreasing over time during the early morning hours. Low level
forcing along the baroclinic zone looks to linger for much of
Sunday, resulting in some more 15-30% chances for showers and
storms, with the highest chances in northeast Nebraska.

By late Sunday into Monday, will see stronger forcing for ascent as
two shortwave trofs will fuse together at H5 across the Northern
Plains. With the boundary lingering across central Nebraska and
eventually tracking northeast, more shower and storms (20-30%
chance) develop and track northeast.

The H5 ridge over the southwest US will amplify late Monday into
Tuesday. Model guidance suggests several shortwaves will ride this
flow leading to precipitation chances (15-30%) mainly in the
nighttime hours Tuesday through Thursday. As the H5 ridge builds,
will also see the 1000-500 mb thicknesses climb implying that
temperatures will warm for much of the extended. NBM extended
currently shows highs potentially reaching the upper 80s to low 90s
by Thursday. Dew points will also be on the rise, resulting in the
air feeling somewhat uncomfortable.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1137 PM CDT Fri Aug 1 2025

Visibilities have improved slightly since 00z, particularly from
western IA into far eastern NE where current observations
indicate 6-10SM. Farther west, 3-6SM visibilities are being
reported; the worst of which are in portions of northeast NE.
The latest HRRR near-smoke forecast is suggestive that
visibility restrictions are most probable overnight at KOFK and
KLNK, with increasing smoke concentrations moving into the KOMA
vicinity by mid/late Saturday morning. Some patchy fog formation
is also possible at KOFK overnight. This forecast update will
indicate prevailing VFR conditions with periods of smoke at 6SM.
The models do still hint at the potential for isolated showers
in parts of northeast NE late tonight into Saturday morning. No
SHRA will be included at KOFK due to low confidence in
occurrence. Light east-southeast winds will increase from the
southeast Saturday morning with sustained speeds of 11-12 kt
expected at KOFK and KLNK.

&&

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

&&

$$

DISCUSSION...Castillo
AVIATION...Mead