171
FXUS63 KOAX 161739
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1239 PM CDT Mon Jun 16 2025

.KEY MESSAGES...

- Severe storms and heavy rain will be possible (15-30% chance)
  from 3 PM onward into the evening and overnight hours. Storms
  will be most intense early on, with gusts in excess of 75 mph
  possible alongside large hail, and localized flooding being
  the main concerns.

- Severe storms (15% chance) and heavy rain potential (5-30%
  chance) return Tuesday, possibly lingering into Wednesday
  extreme southeast Nebraska and southwest Iowa.

- 50-75% chance for oppressive heat overspreading the central
  plains Friday and persisting through the weekend, with heat
  indices expected to reach at least 100 degrees.

- Cooler temperatures in the lower 80s both Tuesday and
  Wednesday as a front moves into the area, accompanied by
  scattered to numerous showers and thunderstorms.

&&

.DISCUSSION...
Issued at 405 AM CDT Mon Jun 16 2025

Today:

Water vapor imagery this morning features northeastward-pointing
ridging through the southern portion of the Intermountain West,
while a jet streak pushes further eastward along its northern
periphery. A potent MCS continues its march to the east across the
Northern Plains, while remnants of less resilient convection
continue to decay across central Nebraska. A short warm front is
draped southward across far western Iowa, with some lower
visibilities of 5 miles showing up in some of the observations
that will continue through shortly after sunrise. Strong to
severe storms continue to be the main focus for today, with many
hazards on the table that change over time and by location.

Over the course of the late morning and early afternoon, the surface
pattern is expected to deepen along the central High Plains,
helping to increase winds and reinforce a boundary stretching
from northeast Colorado to north-central Nebraska, where it then
straddles the NE/SD border as it extends eastward. Moisture
pooling and steep lapse rates will provide substantial
instability along the boundary`s length, while the increasing
mid/upper flow from the aforementioned jet streak help
facilitate shear supportive of intense convection in the form of
supercells and clustered storms. Hazards initially would be
large hail (especially in supercellular structures) and winds
potentially in excess of 75 mph thanks to a deep and well-mixed
boundary layer. Though storm bases are high, a low-end tornado
threat also exists initially along the front, as ambient
vorticity becomes collocated with and stretched by strong
updrafts. Heavy rainfall will also be of concern, where storms
may fester along the front as they grow upscale and take a bit
to form a cold pool.

Latest runs of the CAMs depict convection beginning to fire as early
as 4 PM, with a congealed line of storms taking shape by 9 PM. By
this time, a more focused cold pool will begin to move the
convective line southward, moving southeast through the forecast
area and coalescing with convection moving in from west-central
Nebraska. Storm intensity should be weaker overnight, but will still
be capable of marginally severe hail and wind while the flooding
threat continues under the combining storm clusters. Residual
convection overnight will continue to be possible on the northern
edge of LLJ nosing across south-central into southwest Nebraska, but
will generally be just west of the area. Storms should finally let
up shortly after sunrise tomorrow morning, with storms having
dissipated slowly as they push southeast overnight.

Tuesday and Wednesday:

We`re still eyeing severe storm and heavy rainfall chances Tuesday,
though location of the greatest threat will depend entirely on the
evolution of the strong convection Monday afternoon/overnight. With
that said, the latest runs of extended CAMs places the southerly-
displaced front across northern Kansas, which will serve as the
focus for initial storm development. Convection is expected to
move northward into southeast Nebraska during the early evening
hours, before more widespread convection ignites to the west,
aided by mid/upper forcing associated with a stronger
shortwave. A large cluster of storms will the sweep across the
KS/southern NE area late during the evening hours into early
Wednesday, with heavy rain, damaging wind, and marginally
severe hail being the main hazards. With the front pushed to
the south of the forecast area, so too will the better
hodographs shift, leaving our only chances (while very low at
this point) being associated with QLCS processes overnight as
the cluster of storms moves to the east. Lingering rain and
rumbles of thunder will linger into the morning and early
afternoon hours of Wednesday, as temperatures fall into a very
comfortable range within a couple of degrees of 80 underneath
clearing skies with northwesterly winds.

Thursday through the Weekend:

The extended forecast will see the mid/upper flow push a squat ridge
through the forecast area, shunting better rain chances to the north
and east aside from ~20% chances Thursday associated with a diving
shortwave that glances us to the northeast. Temperatures will climb
well into the 80s Thursday before pushing well into the 90s Friday,
and making runs at near 100 degrees closer to central Nebraska
through Sunday. Forecast numbers continue to be somewhat
conservative compared to the raw model output, but regardless,
we`ll see oppressive heat and an early peek at the dog days of
summer. If dewpoint temperatures trend upwards alongside the
highs, we could be looking at a real chance for our first Heat
Advisory of the year.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1239 PM CDT Mon Jun 16 2025

Main forecast concern will be timing of potential thunderstorms
and associated MVFR to IFR conditions. There remains a large
spread in guidance with some firing storms in northeast
Nebraska, including near OFK by 21Z and pushing those southeast
toward OMA and LNK by 23-00Z. However, more likely scenario is
that storms go up later, pushing toward OFK by 02Z and
overspreading the rest of the area overnight. A few storms could
be severe with damaging winds and large hail. Otherwise, outside
of storms expect VFR conditions with southerly 10-12 kt winds
this afternoon with a few gusts of 20 kts. Winds will be lighter
Tuesday with somewhat variable direction.

&&

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

&&

$$

DISCUSSION...Petersen
AVIATION...CA