854
FXUS63 KOAX 010413
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1113 PM CDT Mon Aug 31 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 /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 614 PM CDT Mon Aug 31 2026

Widely scattered showers and a few storms are observed near the
KOMA terminal this evening. Expect these showers to largely
decrease in coverage within the next hour or two leaving behind
scattered to broken ceilings of 10,000 to 14,000 feet. The bulk
of the activity is expected to remain away from the terminal at
this time. Thereafter, will see VFR conditions prevail for the
duration of the period. Winds remain under 10 kts and variable
at times overnight before becoming southeasterly Tuesday
morning. Latest model guidance suggests potential for storms
that could affect terminals after 06z and 15z, particularly at
KOFK and KOMA (20-30% chance). Confidence remains well below 50%
for inclusion in TAF at this time. LLWS will overspread the KLNK
terminal after 08z and persist to about 12z.

&&

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

&&

$$

DISCUSSION...Castillo
AVIATION...Castillo