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185
FXUS63 KOAX 071043
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
543 AM CDT Mon Jul 7 2025

.KEY MESSAGES...

- Scattered showers and thunderstorms remain possible (30-45%
  chance) late this morning into the early afternoon.

- A cluster of strong to severe storms is expected this evening
  into the overnight hours. Damaging wind gusts (60-70+ mph)
  will be the main threat, especially in northeast NE, though
  hail, a brief tornado, and locally heavy rainfall are all
  possible.

- Intermittent storm chances persist through the week, with
  Thursday standing out as another day to monitor for potential
  severe weather. Repeated rounds of rainfall could also lead to
  localized flooding.

&&

.DISCUSSION...
Issued at 235 AM CDT Mon Jul 7 2025

Today and Tonight...

Water vapor imagery this morning reveals a mid- to upper-level ridge
centered over the Four Corners region, leaving much of the area
under zonal to northwesterly flow aloft. This setup will allow a
series of shortwave disturbances to round the ridge and bring
multiple chances for showers and storms throughout the week. At the
surface, calm winds and a humid air mass will allow for patchy to
widespread fog/low-level stratus to develop across the area, which
should gradually improve after sunrise. Afternoon highs are expected
to range from the mid 80s to low 90s.

Today looks to be an active weather day with two round of showers
and thunderstorms possible. The first chance arrives in the late
morning to early afternoon as a shortwave disturbance and associated
vorticity maxima traverse the region. CAMs vary in their depiction
of this round, with the HRRR showing minimal development while the
Fv3, NSSL-WRF and NAM Nest suggest a quick-moving round of scattered
storms. Should storms develop, brief gusty winds and small hail will
be possible, supported by 1500+ J/kg of MLCAPE and bulk shear of 20-
25 kts. However, the weaker shear will likely limit storm
organization, and cold pools may become quickly unbalanced. PoPs for
this round range from 30-45% through the afternoon.

The more substantial severe weather threat arrives this evening into
the overnight hours. Thunderstorms are expected to initially develop
as isolated supercells along a lee surface trough in western NE and
SD during the afternoon. These storms are then expected to congeal
into an MCS and track east-southeast into northeast NE by the
evening and push south across eastern NE and southwest IA through
the first half of the overnight period. The severe threat will be
maximized in northeast NE as the MCS enters the area. If early-day
convection clears in time for sufficient airmass recovery, this area
will be primed with steep mid-level lapse rates (7-7.5 deg/km),
potent MUCAPE values (2500+ J/kg), and improved shear profiles (35-
40 kts bulk shear), supporting all severe hazards. Damaging wind
gusts (60-70+ mph) will be the primary concern as DCAPE values near
1000 J/kg. Hail (up to 1-1.50") will be possible under stronger
updrafts, and a brief tornado can`t be ruled out if any discrete or
semi-discrete structures persist, given modest low-level curvature
in model hodographs.

Locally heavy rainfall is also possible, with PWATS ranging from
1.50-1.75" and warm cloud depths of 3-4 km, though the progressive
nature of the MCS should limit the potential for widespread flooding
concerns. WPC does have the area in a marginal risk (level 1 of 4)
for excessive rainfall. The system is expected to gradually weaken as
it moves southward, with most of the area clearing out by mid to
late morning Tuesday. PoPs with this round peak in the 60-90% range.
SPC currently places northeast NE in a slight risk (level 2 of 5)
for severe weather, with a marginal risk (level 1 of 5) extending
across much of eastern NE and west-central IA.

Tuesday and Wednesday...

In the wake of Tuesday morning`s MCS, the atmosphere will likely be
overworked, favoring drier conditioned across the area. While a few
spotty showers can`t be entirely ruled out, this period appears to
offer the best window for dry weather this week. High temperatures
on Tuesday are expected to reach the mid to upper 80s, with the low
90s possible on Wednesday. Another weak shortwave disturbance and
accompanying vorticity maxima is expected to move through the region
Wednesday evening into early Thursday, bringing a low-end chance for
precipitation (PoPs 15-30%). At this time, the threat for severe
weather appears low.

Thursday...

By Thursday, two separate H5 lows, one currently positioned off the
coast of British Columbia and another off the coast of California,
are expected to move eastward and eventually merge into a more
pronounced mid- to upper-level trough approaching the northern
Plains. In advance of an associated surface trough, low-level
moisture advection and a tongue of very strong instability is
expected to pull into the central and northern Plains. Thursday
afternoon is expected to bring the warmest temperatures of the week,
with highs ranging from the upper 80s to mid 90s. While long-range
guidance continues to vary on the exact timing and placement of
severe weather, Thursday is shaping up to be a day worth monitoring.
GEFS-based machine learning guidance highlights a broad swatch of 10-
15% severe weather probabilities extending from Nebraska into the
Dakotas. PoPs currently increase Thursday afternoon, peak Thursday
night (PoPs 40-60%), and gradually taper off into Friday.

Friday and Beyond...

A brief cooldown is expected Friday into Saturday following the
departure of the midweek system, with high temperatures dipping into
the low 80s. Heading into the weekend, the broad upper-level pattern
will remain similar to this week, featuring riding over the
southwestern CONUS and zonal to northwesterly flow aloft. This setup
will continue to support occasional precipitation chances as weak
shortwave disturbances track through the region. Temperatures are
expected to return to seasonable conditions with highs generally in
the upper 80s.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
-- Changed Discussion --
Issued at 537 AM CDT Mon Jul 7 2025

Patchy fog this morning is bringing MVFR to even brief periods
of LIFR conditions across eastern Nebraska, with the highest
confidence in impacts at KOFK before returning to VFR conditions
by 13-14Z. Scattered showers are possible (30-45% chance) in
the late morning and afternoon, though confidence in coverage
was too low to include in the TAFs at this time. Calm
northeasterly winds will gradually veer to southeasterly this
afternoon.

Attention then turns to a cluster or strong to severe storms
that is expected (60-90% chance) to push into northeast
Nebraska this evening and dive southward into the overnight
period. MVFR conditions and strong wind gusts (30+ kts) will be
possible as the storms push through the area.
-- End Changed Discussion --

&&

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

&&

$$

DISCUSSION...Wood
AVIATION...Wood