979
FXUS63 KOAX 301920
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
220 PM CDT Sat Aug 30 2025

.KEY MESSAGES...

- Cool and wet conditions are expected through the holiday
  weekend.

- Multiple rounds of heavy rain and embedded thunderstorms
  through Monday could lead to localized flooding, though the
  risk for damaging winds or hail remains low.

- Temperatures stay on the cool side into next week, with highs
  in the 60s to low 70s.

&&

.DISCUSSION...
Issued at 216 PM CDT Sat Aug 30 2025

Today through Monday...

Water vapor imagery this afternoon displays a mid- to upper-level
high centered over western TX, with a mid- to upper-level trough
over the northeastern CONUS. Between these features, a vorticity
maxima is sliding through the zonal to northwesterly flow present
across west-central Nebraska. A messy cluster of additional
vorticity maxima are present across the Dakotas, with guidance
continuing to consolidate these disturbances into a mid-level low
with an associated surface low that slowly drifts southeast across
east-central NE through the holiday weekend. As of 1 PM, surface
analysis places a weak surface low over east-central Nebraska along
with a surface trough extending to its north into south-central SD.

This evolving system will sustain widespread showers and embedded
thunderstorms through the weekend. As of 2 PM, MRMS composite
reflectivity displays a wide area of precipitation across east-
central NE. CAM guidance continues to expand this footprint eastward
through the afternoon and evening, persisting through much of Sunday
and into Monday. PoPs peak overnight into Sunday morning (60-90+%),
gradually tapering off by late Monday (50-75%). The greatest
coverage is expected west of the Missouri River, peaking across east-
central and southeast NE. Persistent cloud cover and rainfall will
hold temperatures below seasonal norms, with highs in the 70s today,
falling to the mid to upper 60s Sunday and Monday. A misty/foggy
start is likely Sunday morning, with visibility reductions in areas
that receive heavy rainfall into the overnight period.

Locally heavy rainfall and flooding concerns remain the primary
focus. Showers will be efficient rain producers given PWATs of 1.50-
1.75", warm cloud depths near 3.5 km, and long, skinny CAPE profiles
on model soundings. However, the weak instability may limit how many
heavy showers are able to initiate. Guidance favors a swatch of 2-3"
totals extending from southeast NE towards the Grand Island-Kearney
corridor, with localized 4-5" amounts possible. Roughly 75% of ECMWF
ensemble members support 3" totals in this area, with 90th
percentile values peaking near 4-5". While rainfall rates may
occasionally approach 1-1.5"/hour under locally heavier showers,
most accumulations will result from the prolonged shower duration.
Flash flood guidance remain on the higher side given our recent dry
conditions (1hr ~2.5", 3hr ~3", 6hr ~3.5-4.5"). Thus, a Flood Watch
has not been issued at this time, though heavier pockets may
approach thresholds. Recent CAM guidance has trended towards keeping
the majority of the heavier pockets just west of our CWA border
(towards the Grand Island to Ord, NE vicinity), but this will be
monitored closely as guidance and convective trends evolve. WPC
maintains a slight risk (level 2 of 4) for excessive rainfall across
eastern NE today and Sunday.

Given the relatively weak instability (MLCAPE <500 J/kg) and bulk
shear (<20 kts), severe weather concerns remain low. However,
frequent lightning will accompany any embedded storms, something to
be mindful of if you have outdoor plans over the long weekend. Given
the proximity to the surface low on Sunday, we could see the
potential for a few funnel clouds, particularly in east-central NE.
However, funnel clouds under these conditions rarely reach the
ground.

Tuesday and Beyond...

By Tuesday, precipitation is expected to taper off (PoPs 15-30%) as
the departing low gradually becomes absorbed into a broad trough
over the east-central CONUS. Partial clearing may allow highs to
step back into the 70s. Late Tuesday night into Wednesday, a
vigorous shortwave trough tracking across Manitoba/Ontario toward
the Great Lakes region will drive a cold front through the region.
Precipitation chances (20-40%) returns ahead of the front`s passage.
In its wake, a seasonable strong speed max will usher in cooler air.
Highs on Wednesday and Thursday are expected to fall into the 60s,
with overnight lows dipping into the 40s and 50s, roughly 15-20
degrees below seasonal norms.

Cooler-than-average conditions are expected to persist through the
remainder of the work week as strong northwesterly flow dominates.
The CPC 6-10 day outlook (valid Sep 4-8) strongly favors below-
normal temperatures across much of the east-central CONUS.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1159 AM CDT Sat Aug 30 2025

Widespread showers with embedded thunderstorms continue to
overspread much of eastern Nebraska this afternoon. VFR
conditions are generally favored through this evening, though
pockets of MVFR to IFR conditions will be possible under the
heavier showers. Showers are already approaching KOFK and KLNK
as of 17Z and are expected to approach KOMA by 20-22Z,
continuing through the bulk of the forecast period. The best
chance for heavier showers and thunderstorms is at KOFK during
the mid afternoon.

Conditions at KOFK and KLNK are expected to diminish overnight
as low ceilings and potential fog/mist builds in, bringing
persistent MVFR to IFR conditions for much of Sunday morning.
Confidence is low in these conditions impacting KOMA, though it
will be possible if the heavier rain shifts eastward later
today. East- southeasterly winds will continue at speeds less
than 12 kts, though brief gusts of 15-20 kts will be possible
under heavier showers.

&&

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

&&

$$

DISCUSSION...Wood
AVIATION...Wood