848
FXUS63 KOAX 122331
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
631 PM CDT Wed Aug 12 2026

.KEY MESSAGES...

- There is a 60 to 80% chance for showers and storms for areas
  along and north of Interstate 80 after midnight tonight.
  Storms will likely be severe with damaging wind gusts, some of
  which could be significant (65-80 mph), and heavy rainfall
  which may lead to flash flooding.

- More showers and storms develop Thursday evening into Friday
  morning (40-60% chance). Some storms could be strong.

- Periodic shower and storm chances continue through the weekend
  into early next week. Cooler temperatures arrive for Sunday
  through Tuesday.

&&

.DISCUSSION...
Issued at 111 PM CDT Wed Aug 12 2026

.SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...

1752z KOAX radar imagery shows widely scattered showers and a few
storms across the southern half of the forecast area. This activity
is largely driven by warm advection at H7 and H8 providing ascent
near the baroclinic zone. This activity will fester across the area
this afternoon, but should largely stay sub-severe. Expect another
warm and humid day with highs in the upper 80s to low 90s and heat
indices in the upper 90s to near 105F.

Our attention in the short term then turns to the severe convection
threat for late tonight into Thursday morning. An H5 impulse will
approach the Dakotas and western Nebraska this afternoon/evening.
Large scale forcing for ascent should be a bit stronger than this
morning`s wave, and combined with some sfc convergence seen in the
vicinity of an approaching low, will likely see storms fire. CAMs
show convection firing off over most of western Nebraska into the
Dakotas around 00z, congealing into an MCS and pushing eastward into
eastern and northeastern Nebraska after 05z. Maintenance of the MCS
appears likely, as the 30 to 40 kt H8 LLJ will point into much of
the forecast area throughout the night, helping provide additional
fuel and lift for the feature. Forecast soundings show 2,000 to
3,000 J/kg of MUCAPE rooted at or above H8 with little CIN, and
thinking is that the jet should provide enough forcing to lift
parcels up. 0 to 6 km bulk shear of 35 to 45 kts should keep the
feature organized. Given the rather large amounts of DCAPE seen from
forecast soundings (1,000-1,200 J/kg) the primary threat from storms
will likely be damaging wind gusts in addition to some hail. Model
runs of the HRRR have been fairly consistent in bringing a ribbon of
65-80 mph gusts across a few areas of northeast Nebraska. At
this time, the SPC has a slight risk (level 2 of 5) of severe
weather for much of the forecast area.

In addition, the environment remains primed for heavy rainfall as
warm cloud depths of 4,000 to 4,500 J/kg are progged over most of
the area with PWATs of 1.9 to 2.5 inches at times, well above the
90th percentile of sounding climatology. Flash flooding will likely
occur in areas that experience repeated passage of storms or already
experienced heavy rainfall earlier this morning. The heaviest QPF
axis will lie primarily across northeast Nebraska where HREF
guidance shows a 60% chance of seeing an inch or more of rain.
Probabilities significantly taper off to 20% for 2 inches or more.
Certainly will want to pay attention to the forecast late tonight
into Thursday morning and make sure to have multiple ways to
receive warnings overnight should any be issued. At this time,
PoPs gradually increase in coverage after 04z for areas north of
the Platte River (15-40%), then ramp up to 60 to 80% across
that same area after 06z. PoPs slowly taper off after 16z across
most of the forecast area.

Slightly cooler highs arrive by Thursday with most locations seeing
the upper 70s to mid 80s. Far southern areas bordering Kansas could
see the mid to upper 90s. With the H5 ridge remaining firmly in
place across the Southern Plains into the southeast US, the
southwesterly flow will result in another shortwave approaching the
area late Thursday. The feature will aid in producing some more
chances for rain and storms Thursday evening into Friday morning (40-
60% chance). Storms could once again be strong with ample buoyancy
in place and shear of 30 to 35 kts.

.LONG TERM /FRIDAY THROUGH TUESDAY/...

Disturbances will continue to ride the H5 northwestern periphery of
the ridge, resulting in continued chances for showers and storms,
likely in the evening and overnight periods. The best chances for
storms appear to be early Friday morning (50-70%) in northeast
Nebraska and areawide Saturday night into Sunday (50-70%). Some low
end potential exists that storms could be strong, particularly
Friday. Storm chances persist into Monday and Tuesday, but remain
fairly low at less than 30%. Highs on Friday and Saturday remain
similar to Thursday`s highs, while cooler temperatures in the 70s
and 80s arrive for Sunday through Tuesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 622 PM CDT Wed Aug 12 2026

Have made some minor changest to approaching precip:

A) Sped up timing on thunderstorm arrival at KOMA by an hour
(now 4am) although that confidence is still low.

B) Removed precip at Lincoln. Could stil see storms around the
3am to 5am period, but expect a less than 30% chance there.

C) Also lowered expected cigs into MVFR category.

&&

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

&&

$$

DISCUSSION...Castillo
AVIATION...Nicolaisen