499
FXUS63 KOAX 281933
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
233 PM CDT Mon Sep 28 2026

.KEY MESSAGES...

- Widespread rainfall amounts of 2 to 4 inches are expected
  through Thursday, with a narrow band of over 5 inches in some
  locations. A Flood Watch has been issued for Tuesday evening
  through Thursday.

- If we get any clearing on Wednesday, a few strong to severe
  thunderstorms will be possible during the afternoon and
  evening, mainly in southeast Nebraska.

- Rain will end Thursday night, with cooler, dry conditions
  expected through the weekend.

&&

.DISCUSSION...
Issued at 233 PM CDT Mon Sep 28 2026

Early afternoon analysis showed an upper level ridge axis
passing through with low level clouds slowly but surely eroding
from south to north. Temperatures as of 1 PM were in the mid 60s
to lower 70s.

The main focus in the forecast will be widespread rainfall
expected Tuesday through Thursday. A strong upper level trough
currently over the Desert Southwest remains on track to ingest
tropical moisture from Hurricane Polo and edge eastward on
Tuesday with a surface low spinning up ahead of the trough and
eventually pushing northeast toward the area on Wednesday. In
addition, we`ll have a decent stream of moisture coming in from
the gulf which, when combined with the tropical moisture from
the southwest, will lead to precipitable water values exceeding
2 inches per NAEFS and EPS guidance, exceeding the
climatological maximum for this time of year. As warm air
advection and moisture transport ramp up ahead of this system,
showers and storms will develop to our west and push into
northeast NE by early Tuesday morning. Precip will gradually
overspread the area, lingering through Thursday before a cold
front slides through and pushes the precip out.

With the aforementioned moisture availability/origin, moisture
transport pointing into the area, and warm cloud depths
exceeding 4 km, all the ingredients appear to be there for some
very efficient rain producing showers and storms. Add in the
fact that most of the area has received 2 to 5 inches of rain in
the last couple weeks leading to saturated soils and slightly
elevated river levels, we`re primed for flooding impacts. The
big question is where the heaviest band of rain will fall. Model
consensus paints a broad band of 2-4" across much of the
forecast area through Thursday with individual models
highlighting potential for a narrow (~30 mile wide) band of 5-7
inches somewhere in there. Unfortunately, there remains quite a
bit of spread in that band, with solutions ranging from it
falling across central into far northeast NE to north-central KS
into far southeast NE/far southwest IA. For what it`s worth,
highest probabilities for those 5+ inch amounts (20-30% chance)
stretch from Butler County, east through the Omaha metro area
and northeast into Harrison/Shelby Counties. Obviously, where
that falls will significantly impact which rivers will see the
highest potential for flooding, but at this point, at least the
Missouri, Platte, Elkhorn, Big Blue, and Nishnabotna Rivers all
have at least some potential for flooding. As such, a Flood
Watch has been issued for much of the area from Tuesday evening
through Thursday. Keep a close eye on the forecast, especially
if you have interests near rivers.

If the flooding potential wasn`t enough, there is at least some
small concern for severe thunderstorms, especially on Wednesday
as the surface low pushes closer to the area. While most
guidance suggests we`ll be cloudy and rainy much of that time, a
few "extended" CAMs (e.g. 28.12Z NAMNest) hint at a little
instability building across far southeast NE with very curvy
low-level hodographs immediately northeast of the low. If this
pans out, would need to keep an eye on severe storms potential,
particularly tornadoes. Very low confidence that this pans out,
but worth monitoring with such a dynamic system on the way.

As mentioned above, a cold front will pass through sometime
late Thursday and bring an end to the precip with surface high
pressure building in. A few weak shortwave troughs look to pass
by just to our north Friday and Saturday, but consensus
generally keeps associated precip out of our area, giving us
only a 5-10% chance High temperatures will be in the upper 60s
to mid 70s through Wednesday, with lower to mid 60s through the
weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1246 PM CDT Mon Sep 28 2026

Mostly MVFR ceilings will linger early in the period, but
guidance continues to suggest they`ll eventually scatter out,
with clouds bases around 4000-6000 ft thereafter, though
confidence in exact timing isn`t particularly high (it may end
up being later). Attention then turns to incoming shower and
storm chances Tuesday. Latest guidance suggests at least showers
will move through OFK by 18Z, but hold off at OMA and LNK until
after the period. Otherwise, winds will stay steadily out of
the south to southeast around 10 kts, with a few gusts
approaching 18-20 kts on Tuesday.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Flood Watch from Tuesday evening through Thursday evening for
     NEZ015-018-030>034-042>045-050>053-065>068-078-088>093.
IA...Flood Watch from Tuesday evening through Thursday evening for
     IAZ043-055-056-069-079-080-090-091.

&&

$$

DISCUSSION...CA
AVIATION...CA