738
FXUS63 KOAX 162026
AFDOAX

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

.KEY MESSAGES...

- Severe storms and heavy rain will be possible (15-30% chance)
  into the evening and overnight hours tonight. 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/flooding potential
  (5-30% chance) return Tuesday, especially in southeast
  Nebraska into southwest Iowa, though questions remain on
  north/south extent of storms.

- 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.

&&

.DISCUSSION...
Issued at 326 PM CDT Mon Jun 16 2025

Early afternoon analysis showed a surface cold front stretching
from near Mitchell, SD, southwest into northeast/north-central
NE and into the NE panhandle. By 2 PM, a few storms had fired in
southeast SD and convection was starting to "zipper" down the
front. There was still fair amount of MLCIN in place ahead of
the front, and some fairly dry low level air per the 18Z OAX
sounding farther southeast, so generally think convection should
be on a downward trend as it pushes southeast the rest of this
afternoon into this evening. Still, do think it will continue
for a few hours despite many CAMs suggesting otherwise, as deep
moisture convergence will slide into northeast NE. They`re not
perfect, but the 16.12Z NSSL WRF and and NAM Nest solutions seem
to make sense with storms going up in northeast NE/southeast SD
with potential for supercellular structures at times producing
a large hail, damaging wind, heavy rain, and even a low-end
tornado threat this afternoon. Eventually things should congeal
along southeastward-moving outflow boundary with additional
storms along it, but they should generally run out of steam as
they approach the Platte River. All that said, a less probable,
but possible scenario depicted by the HRRR could pan out where
we only get spotty convection along the boundary through the
afternoon. Instead we`d wait for a shortwave currently in
eastern WY to push in around or just after midnight and bring an
MCS and mainly a damaging wind and heavy rain/flooding threat.

The MCS moving through into early Tuesday will help push
instability largely to our south and while we should see a break
in precip during the morning, lingering cloud cover should
still help to limit instability building through much of the
area during the day. Still, guidance is in decent agreement that
the surface boundary and instability plume still remain in
place across portions of southeast NE and into southwest IA,
though a few solutions keep them to our south. Low level
moisture transport will point into that boundary by the
afternoon and lead to more storm development heading through the
evening and overnight hours. Along the boundary, shear profiles
look sufficient for all severe weather hazards. In addition,
ingredients are in place for training storms to lead to heavy
rain and flooding (1.75" to 2.00" precipitable water, warm cloud
depths of 3750 m, and strong moisture transport pointing
directly into a boundary). Several CAMs do have pockets of 3"+
rainfall totals near the boundary, but again, still some
differences on north/south placement of the boundary that we`ll
need to work out.

Tuesday night into Wednesday, a surface low will develop
northeastward into eastern IA and while our severe weather
threat should be over on Wednesday, we`ll likely have some
lingering showers and isolated storms through the day.
Temperatures will also be more comfortable, with highs in the
upper 70s to lower 80s.

Precip should exit by Wednesday evening with the surface low
pushing into the Great Lakes and surface ridging moving through
overnight. By Thursday morning, southwesterly flow will return
with a warm front advancing northward through the area. This
will bring a return of warm, humid weather as temperatures get
back in the mid 80s to lower 90s. Several pieces of guidance
suggest we`ll see some storm development along the warm front by
Thursday afternoon/evening, with consensus suggesting northeast
NE/west-central IA would see the highest chances (30-40%). Still
a little early to determine severe weather potential with
plenty of smaller scale details to work out, but initial looks
suggest there would be sufficient instability and shear for at
least a small threat.

Upper level ridging starts to build in Friday through the
weekend with southerly flow continuing to usher in warm, humid
air. We should see widespread 90s Friday through Sunday with
dewpoints in the mid 60s to lower 70s. The warmest day currently
looks like it`ll be Saturday when several spots could make a
run over 100 degrees with some heat indices approaching 105/heat
advisory criteria. NAEFS guidance does indicate 850 mb
temperatures in the 25 to 28 C range, good for the 99th
percentile of climatology and mixing those down would get us
into the 100s. So bottom line, looking hot for the weekend.

&&

.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...CA
AVIATION...CA