595
FXUS63 KOAX 060530
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1230 AM CDT Sun Sep 6 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms are expected mainly Sunday
  afternoon and evening. A few storms may become strong to
  severe, with isolated strong winds, hail and heavy rainfall
  the main hazards.

- Above-average temperatures continue through Tuesday, with
  highs generally in the low to mid 90s.

- A cold front will move through Tuesday into Wednesday,
  bringing high temperatures in the 80s along with periodic
  chances for showers and thunderstorms.

&&

.DISCUSSION...
Issued at 1027 PM CDT Sat Sep 5 2026

Tonight and Sunday...

Water vapor imagery and objective analysis late this evening depicts
a high amplitude mid-level ridge over the central CONUS, with a
cutoff low moving onshore over the Pacific Northwest. At the
surface, high temperature peaked in the low to mid 90s under the
persistent ridge, approximately 10 degrees above average for early
September. Dewpoints soared into the low 70s, pushing heat index
values into the 102-107 degree range. As temperatures cooled through
the evening, the Heat Advisory was allowed to expire.

Overnight, convection is expected to develop along a lee trough over
western Nebraska before gradually progressing eastward along the LLJ
into the mid to late morning hours. Some questions remains regarding
storm coverage and intensity as they progress towards the area,
given the rather unimpressive bulk shear (20 kts). Intermittent CAM
guidance also sparks more isolated storm development in northeast
NE/southeast SD overnight along the LLJ nose, though confidence in
this scenario remains a bit lower given the subtle forcing. However,
storm coverage is expected to become more widespread through the
late morning and early afternoon as increasing low-level warm air
advection noses into a surface front draped near the mid-MO Valley
as mid-level disturbance pivots over the area. A corridor of
modestly improved bulk shear around 25 kts will overlap steepening
lapse rates and modest instability across far eastern Nebraska and
western Iowa, supporting some potential for strong to severe storms.

The primary hazards will be pockets of hail and damaging wind gusts
as individual cores quickly pulse within a broader, more upscale
cluster. Potential also exists for pockets of heavy rainfall given
that storms may train over the same for an extended period of time.
Efficient rainfall processes will be in place with PWAT values of
1.75-2.00" (above the 90th percentile of sounding climatology for
early September) and warm cloud depths of 4-4.5 km. CAM guidance
hints of pockets of 2-4" rainfall totals, particularly over
northeast Nebraska into western Iowa where convection is more
persistent.

Although cloud cover and precipitation chances will increase through
the day, high temperatures will still make a run at hitting the
upper 80s and low 90s prior to convection becoming more widespread,
bringing yet another above-average early September day. Heat index
values are expected to peak in the 95-100 degree range, just shy of
Heat Advisory criteria. Precipitation chances will taper off through
the overnight period into Monday morning.

Monday and Tuesday...

Into the work week, the aforementioned mid-level low positioned over
the Pacific Northwest will gradually deepen and pull east along the
US/Canada border, helping to flatten the ridge in place and push a
cold front through the area. Long range guidance varies on the exact
timing of the frontal passage, though it looks to sweep southward
across the area through the day Tuesday and into early Wednesday.
Ahead of its arrival, Monday will be yet another day of widespread
highs in the upper 80s to mid 90s, with heat index values around
100. A tightening surface pressure gradient ahead of the approaching
system and mixing into stronger winds aloft will bring southerly
wind gusts of 25-35+ mph on Monday.

High temperatures on Tuesday will depend on how quick the northeast-
to-southwest oriented cold front pushes southward across the area.
Highs are expected to reach the mid to upper 90s, with heat index
values around 105, across southeast NE and southwest IA, with values
peaking in the upper 80s further north where the front passes
through before peak daytime heating. Chances for showers and storms
exist along the front, with machine learning guidance placing a 5-
15% probability of severe weather. With the better large-scale
forcing for ascent displaced to the northeast, details will likely
hinge on mesoscale features that come into focus with time, though
sufficient instability and improved bulk shear will be in place for
a few stronger storms. For now, PoPs of 60-80% exist through Tuesday
and early Wednesday as the front pushes through.

Wednesday and Beyond...

Zonal flow aloft will return by mid-week, pushing high temperatures
back into the 80s. Periodic PoPs of 15-30% remain in place through
the remainder of the week as shortwave disturbance traverse the
area. Good news for the fall-lovers, looking further ahead, most
GEFS and EPS-AIFS members bring a potent trough across the northern
Plains next weekend. This system will bring a push of cooler air
into the region and could knock highs in the 70s by the end of next
weekend, though details on timing and extent will still need to be
ironed out.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1222 AM CDT Sun Sep 6 2026

VFR conditions are forecast over the next 24 hours with some
caveats. Thunderstorms are possible as early as 9am in parts of
the area, but confidence is low in placement and timing. For
that reason, have not included in the TAF forecast. However,
storm chances continue through much of the daylight hours on
Sunday, especially at KOFK and KOMA at about 15-30% chance each
hour. Will add timing to the TAFs if/when confidence in a
solution emerges.. perhaps with the 12Z issuance.

Otherwise expect 5-15 knot winds out of the southeast.

&&

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

&&

$$

DISCUSSION...Wood
AVIATION...Nicolaisen