447
FXUS63 KOAX 010502
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1202 AM CDT Tue Sep 1 2026

.KEY MESSAGES...

- 15-30% chance for some scattered showers or storms early
  Tuesday morning across northeast Nebraska. Highs warm to the
  90s with heat index values of 100+ across southeast Nebraska
  into southwest Iowa.

- 40-60% chance for storms after 8 pm across northeast Nebraska.
  Storms could be severe with large hail, damaging winds, and a
  small risk for a tornado.

- Hot and humid weather continues into the weekend along with
  some small chances for nightly storms. Warm lows in the mid to
  upper 70s will provide little relief overnight.

&&

.DISCUSSION...
Issued at 1113 PM CDT Mon Aug 31 2026

.SHORT TERM /TODAY THROUGH WEDNESDAY NIGHT/...

04z RAP objective analysis shows the 596dam ridge dominating the
Southern Plains into the southeast CONUS, while to the north, a
strong closed H5 low is observed over Manitoba. These two features
place much of the Northern and Central Plains areas in westerly to
southwesterly flow. This should allow for continued passage of mid
level disturbances today and Wednesday.

Early Tuesday morning, will see an H8 baroclinic zone and the
attendant warm air advection move northeastward across the area.
Speed convergence along the nose of the H8 jet could fire some
scattered showers and storms primarily across northeast Nebraska.
Various CAM guidance depicts this activity developing in an
environment with 1,000 to 2,000 J/kg of MUCAPE rooted just below H7.
Should parcels be forced upward, marginal 0-6 km bulk shear in place
could allow some updrafts to become strong and produce large hail or
some gusty winds. With this update, PoPs of 15 to 30% are forecast
across northeast Nebraska after 06z.

Widely scattered showers and a few storms linger across northeast
Nebraska late this morning/early afternoon (15-20% chance), with
some clearing seen thereafter. Expect another hot and humid day
with highs in the 90s and heat index reaching the upper 90s/low
100s along and southeast of a line from Lincoln to Fremont to
Tekamah. By midday, an H5 shortwave will eject from the
Utah/Colorado vicinity northeast toward the Dakotas and
Nebraska. Large scale forcing for ascent tied to the wave along
with convergence driven by a sfc boundary should fire off
scattered storms in central and north central Nebraska,
congealing into an MCS as it tracks east and enters the
forecast area after 8 pm. Forecast BUFKIT soundings show
anywhere from 1,000 to 2,000 J/kg of instability and bulk shear
of 40 to 50 kts promoting the development of severe convection.
High based LCLs combined with mid level dry air would suggest
more of a damaging wind threat with convection as it enters the
forecast area, but should anything remain discrete and can
become sfc based, a tornado can`t be completely ruled out given
good low level curvature seen in hodographs (particularly over
northeast Nebraska). 00z CAMs still suggest subtle differences
in the track of the MCS, with some suggesting a more northward
track and just barely grazing the CWA, to portions of northeast
Nebraska being impacted. With this forecast update, have kept
PoPs at 40 to 60% across northeast Nebraska after 01z through
08z with PoPs tapering down thereafter. Lows tonight cool to the
mid to upper 70s: this will provide little reprieve from heat,
particularly over southeast Nebraska into southwest Iowa.

A few showers linger Wednesday morning before weak sfc high pressure
passes just to the north and east bringing us quiet weather. Expect
another warm day with highs in the 90s again and heat indices of 100
to 105F at times mainly across southeast Nebraska into southwest
Iowa. Similar to tonight, overnight lows only cool to the mid to
upper 70s providing little reprieve from heat.

.LONG TERM /THURSDAY THROUGH MONDAY/...

The southeast CONUS H5 ridge will keep pushing east on Thursday.
Thereafter, will see large scale amplification occur across much of
the central CONUS resulting in our prolonged stretch of hot and
humid conditions through Sunday. Overnight lows remain warm,
primarily for areas along and south of the Platte River into
southwest Iowa through Saturday. Due to the little relief
provided at night combined with consecutive days of 75+ lows in
southeast Nebraska and southwest Iowa, may need to consider
potential heat headlines. For now, have held off issuance after
collaboration with neighboring WFOs, but will likely need to
reassess trends the next day for potential issuance. Our next
chance for storms will be late Wednesday night into Thursday
which could provide a little reprieve from heat and throw a
wrench into heat headlines, but the best storm chances look to
be confined in our far northern areas where minT recovers
better.

Periodic chances for storms will persist into the weekend too, but
chances remain at 15 to 20%, particularly at nighttime and are
likely driven by persistent WAA and any weak disturbances that round
the ridge. A better chance (30-45%) for precip returns late Monday
as the ridge becomes flattened by a potent Canadian trof, but
significant model discrepancies are apparent amongst model
guidance at this time.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1202 AM CDT Tue Sep 1 2026

VFR conditions through the TAF period. Increasing high clouds
from the west tonight with a frontal boundary draped across
southeast Nebraska. We`re watching storm activity over eastern
Colorado which could ride up into northeast Nebraska around 12Z
Tuesday. Not confident in how well they will hold together with
guidance waffling back-and-forth on whether we see anything at
all over NE Nebraska Tuesday morning. Went ahead and added -SHRA
in the TAF for KOFK with my best guess on timing. Could
potentially be lightning, though, so amendments may be needed.
Otherwise, expect quiet weather at KOMA and KLNK under partly to
mostly clear skies through Tuesday. Winds will be increasing out
of the south Tuesday afternoon, more southeasterly at KOFK.
Models show a strong storm complex moves through NE Nebraska
Tuesday evening around 03-06Z. Right now guidance has it staying
north of KOFK, but could change with guidance as we get closer.

&&

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

&&

$$

DISCUSSION...Castillo
AVIATION...McCoy