552
FXUS63 KOAX 151721
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1221 PM CDT Sun Jun 15 2025

.KEY MESSAGES...

- On-and-off shower and thunderstorms chances (15-60% PoPs) into
  the early work week. Severe storm and heavy rain potential
  returns this afternoon and increases into Monday and Tuesday.

- Clouds and scattered rainfall will help knock temperatures
  down into the lower to mid-80s by Tuesday.

- Chances are increasing for oppressive heat moving into the
  Central Plains Friday week into the upcoming weekend, with
  heat indices expected to reach 100 degrees.

&&

.DISCUSSION...
Issued at 404 AM CDT Sun Jun 15 2025

Today and Tomorrow:

Water vapor imagery this morning features a decaying shortwave
continuing to move east through the Ohio River Valley, while a
handful of MCSs push east and southeast across the Northern and
Central Plains. Drilling down to the surface, an ever present
surface front continues to bisect the southwest and northeast
portions of the forecast area, connecting eastward to a weak
surface low located at the MN/IA/WI/IL area. Weak elevated
returns have been traveling southward across eastern Nebraska,
and have resulted in a few sprinkles so far this morning that
have amounted to little aside from a few traces. Highs today
will be in similar territory as yesterday, in the upper 80s to
just over 90 degrees while dewpoints linger in the mid-to-upper
60s.

Looking at storm chances today, the morning hours will see decaying
convection from north-central Nebraska drifting into northeast
Nebraska, while afternoon and evening storm chances will focus
initially along the aforementioned front that will have drifted into
South Dakota. CAMs show two potential solutions for the evolution of
strong to severe storms this afternoon and evening, which should
show it`s hand by mid-to-late morning. The first scenario would be
the convection across north-central Nebraska continuing to fester,
igniting a larger area of scattered storms that move southeast
through the forecast area early afternoon through 9 PM (see the NSSL-
WRFARW and to a lesser extent HiResARW). The second and more
likely scenario would be a more limited area of convection that
would start in southeast South Dakota along the front that would
begin to move south-southeast 7 PM onward -- stretching the
storm risk later into the evening. Weak shear and sufficient
thermodynamics point to only marginal severe hail and wind being
the main threats alongside heavy rain.

Monday`s temperatures should be in similar territory as the
previous days, with an incoming jet streak that helps deepen a
mid/upper shortwave. Better shear thanks to the increase
mid/upper flow will increase the severe storm chances, with
northeastern portions of our forecast area being highlighted in
a level 2 risk out of 5 for severe storms. Exact placement and
initiation times do continue to vary from run-to-run, but the
latest extended CAMs signal storms to begin firing closer to 7
PM along the ever-present stationary front depicted across the
northern rows of counties in Nebraska before zipping into
southeast South Dakota where instability is maximized. These
storms will benefit from increased mid/upper support in
addition to the better shear and thermodynamics, and we will
likely see better chances to beat the baseline severe criteria,
with flooding/training storms along the front possible as well.
Convective activity should carry into the late evening and into
the overnight hours, pushing the stationary boundary southward
headed into Tuesday.

Tuesday and Wednesday:

By Tuesday, the aforementioned jet streak (which is slightly weaker
at this point) will have moved squarely over the area while the main
shortwave axis arrives to make for the forecast`s best chance to see
severe weather and flooding. Deterministic models show the
stationary front draped from west-to-east just south of Interstate
80, serving as a focus for convergence and convective initiation,
while the mid/upper flow pushes storms generally along and east of
the front. Hodographs along and south of the stationary front will
have sufficient curvature for tornado chances, while PWAT values
reach 175% of normal, joining the traditional hail and wind with the
moderately sheared and unstable environment. This convective
activity should continue into early Wednesday with a few post-
frontal showers and storms possible in northeast Nebraska forced by
the mid/upper support, making the most out of steeper lapse rates
despite lower instability. As storms slowly sweep out of the
forecast area Wednesday, we`ll enjoy cooler-than-average
temperatures that return to the upper 70s to low 80s, making for one
of the more pleasant days to be outside as a northwesterly breeze
blows.

Thursday and Beyond:

For the latter part of the forecast period, model solutions are all
in excellent agreement in the progression of a low-amplitude
mid/upper ridge traversing eastward from the western CONUS, helping
to shunt precipitation chances north and west of the forecast area.
The cooler temperatures from the mid-week should begin warming up
Thursday back into the upper 80s, and further warming is anticipated
as the low-level thermal ridge builds from the west. Ensemble
situational awareness tables highlight anomalously warm temperatures
in the 700 and 850 mb fields in both the NAEFS and the EPS. Taking a
look at values in the NBM, they continue to be weighed down by the
recent bias correction, which remains cooler than the explicit
modeled highs because of our cool May/early June. A conservative
nudge up in temperatures over the NBM values gives much of the
forecast area max heat indices that near 100 degrees. This will be
our first heat wave that may catch those outdoors off-guard,
especially with outdoor activities kicking into full-swing.
Precipitation chances aren`t completely out of the question going
into the weekend, but should be the pulse thunderstorms that often
accompany the dog days of summer.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1220 PM CDT Sun Jun 15 2025

Early this afternoon, showers continue to percolate along an
area of greater low- to mid-level theta that extends from TQE to
ONL, affecting the OFK vicinity. Dynamic forcing for these
showers tied to weak mid-level shortwave that is dove-tailed to
a MCV moving across eastern South Dakota. Not noting any
lightning in the weak convection across Nebraska, thus amended
OFK TAF earlier to include VCSH with lowest ceilings 8-10K AGL.
Expect this weak convection to dissipate by 21z and both mid-
level short- wave and MCV move into Minnesota and central Iowa.
CAMS seem to support this evolution keeping convection well east
of OMA this afteroon and early evening. For OMA and LNK,
afternoon and evening generally characterized by scattered to
possibly broken diurnal cumulus at FL040-060, with broken to
overcast ceiling FL at or above 20-25K. Diurnal cumulus expected
to dissipate by 16/01-02Z. Overnight, a MCS is expected to
develop in the western high plains of Wyoming, Colorado and
Nebraska. As complex moves into eastern Nebraska, kinematics
weaken and low-mid level moisture lacking, thus expect complex
to dissipate substantially as it moves into CWA. Thus, impacting
little or no impact to TAF, with convective remnant clouds
generally at or above 120K AGL. There does appear a 40-60%
chance of LLWS conditions developing at both OFK and LNK between
08z-13z due to the low level jet, thus plan to add to OFK and
possibly LNK.

&&

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

&&

$$

DISCUSSION...Petersen
AVIATION...Fortin