751
FXUS63 KOAX 060457
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1157 PM CDT Tue Aug 5 2025

.KEY MESSAGES...

- A few strong to severe storms are possible late tonight into
  Wednesday, with the primary hazards being locally damaging
  winds, hail, and localized flooding.

- Temperatures return to the 90s Thursday and Friday. Localized
  100-105 heat indices on Thursday are expected to become more
  widespread by Friday.

- Cooler this weekend and Monday, with showers and thunderstorms
  possible. Some severe weather and/or flooding could occur.

&&

.DISCUSSION...
Issued at 315 PM CDT Tue Aug 5 2025

     The remainder of this afternoon through Wednesday night...

Early afternoon water vapor imagery and objective analysis
depict a strengthening mid/upper-level high centered along the
U.S.-Mexican border, west of El Paso, TX. On the immediate
northern periphery of that feature, a weak mid-level impulse is
tracking through central NE this afternoon, with a comparatively
stronger short-wave trough moving through central/eastern MT.

The NE disturbance has been associated with a small area of
elevated convection so far today, and it`s not out of the
question that an isolated shower or thunderstorm could occur
as it moves through our area this afternoon into early evening.
More significant thunderstorm development is anticipated later
this afternoon into evening across the northern Plains in
conjunction with the approach of the MT short-wave trough and
attending surface frontal system. Those storms are expected to
evolve into an MCS, with the southern portion of that complex
potentially building into far eastern NE and western IA
overnight into Wednesday morning, on the eastern periphery of a
strong cap in place over the central Plains. Assuming that
scenario unfolds, the potential will exist for isolated
occurrences of damaging winds, hail, and flooding rainfall.

The forecast grows more uncertain by Wednesday afternoon as
latest model data present at least a couple scenarios. The HRRR
has consistently shown the redevelopment of thunderstorms across
portions of eastern NE and western IA, presumably along the
trailing outflow boundary associated with morning storms. Some
severe weather would be possible in that scenario. In contrast,
many of the other models indicate dry conditions through the
remainder of the daylight hours, which is what this forecast
update will follow.

On Wednesday night, the models hint at a low-amplitude
disturbance tracking along the NE-SD border, which could foster
isolated thunderstorm development in far eastern NE and western
IA, along the edge of the stronger capping. Some of that
convection could linger into Thursday morning.


     Thursday and Friday...

A prominent, mid/upper-level low and associated short-wave
trough are forecast to evolve over the Canadian Rockies into
northern Intermountain Region on Thursday, with that system
moving into the northern High Plains on Friday. In the low
levels, a cyclone is forecast to deepen over SD on Friday, with
an associated cold front surging through the western Dakotas at
that time. Increasing south winds ahead of the front --especially
on Friday-- will translate to continued warming temperatures
with highs in the upper 80s to low 90s on Thursday, and lower to
mid 90s on Friday. Localized areas of 100-105 heat indices on
Thursday are expected to become more widespread by Friday.

As mentioned in the previous section, some potential will exist
for a few storms on Thursday morning, with generally dry
conditions anticipated from Thursday afternoon through Friday
afternoon.


     Friday night through Monday...

The mid/upper-level low initially over southern Saskatchewan is
forecast to accelerate toward Hudson Bay in response to another
short-wave trough advancing from the Canadian Rockies into the
northern Plains. The net result is the maintenance of broader-
scale troughing across the north-central U.S. this period. In
the low levels, a cool front is expected to move into the area
Friday night, and potentially linger in the vicinity into
Monday. The presence of that feature will lead to an extended
period of shower and thunderstorm chances, the highest of which
(40-50% PoPs) is forecast on Saturday night and Sunday night.
Given the recent rainfall, soil moisture remains high in some
areas, so localized flooding is a concern, as is the potential
for isolated severe weather.

Temperatures will trend cooler with the arrival of the front,
with highs largely in the 80s.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1151 PM CDT Tue Aug 5 2025

Southeasterly winds continue this evening at just over 10 kts
while even stronger winds have developed at FL015 of 40 kts out
of the southwest to introduce low level wind shear that will
last through the overnight. A thunderstorm complex continues to
form to the north of the terminals in eastern South Dakota, that
should begin to shift more and more easterly over time. Model
guidance has been overly bullish that storms will move into the
KOFK/KOMA sites, with recent trends pushing the arrival at KOMA
later towards 15z and not at all near KOFK. With the uncertainty
and the over-development of the recent model runs, they have
been left out of the TAFs for this cycle. The most likely
scenario is that they main body of storms will miss KOMA and
KOFK to the northeast, leaving only a 20% chance that isolated
storms develop near the sites and south of the main cluster.
Tomorrow afternoon will see gusts return and winds eventually
settle out of the east-southeast before decreasing in speed by
23-00z.

&&

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

&&

$$

DISCUSSION...Mead
AVIATION...Petersen