286
FXUS63 KOAX 300525
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1225 AM CDT Wed Sep 30 2026

.KEY MESSAGES...

- Dense fog potential overnight tonight for northeast Nebraska.

- Have trimmed northern counties out of the Flood Watch due to
  latest guidance trending heavy rainfall farther south. Still
  expect a broad swath of 3-5 inches of rain through Thursday.

- Cooler, dry conditions through the weekend with temperatures
  trending back warmer next week.

&&

.DISCUSSION...
Issued at 1136 PM CDT Tue Sep 29 2026

Clouds across eastern Nebraska and western Iowa tonight as a
plume of moisture continues to stream in from the remnants of
Hurricane Polo as well as the Gulf. An upper-level trough over
Arizona is helping to pull this moisture northward as well as
track these remnants toward our area. Overnight, drier
conditions over northeast Nebraska as well as some potential
clearing of clouds will lead to significant fog development over
a large portion of northeast Nebraska. We could potentially need
a dense fog advisory for this portion of our area by daybreak on
Wednesday.

Overall models have been trending farther south with the track
of the remnants of Polo which takes the band of heaviest
rainfall now more through Pawnee City, Falls City, Nebraska
City in southeast Nebraska, and Shenandoah, Clarinda, and Red
Oak, in southwest Iowa. A couple models continue to hold on to a
more northerly trajectory so I`m not trimming the Flood Watch
quite as far south as I want to, but I am taking out all of our
northeast Nebraska counties. I think the greatest concern for
flooding over the next couple of days will be for rivers such as
the Little and Big Blue Rivers, Turkey Creek, the Big Nemaha,
and West and East Nishnabotna Rivers.

Now for the weather discussion. As the western trough approaches
we`ll see shortwaves bring additional rounds of showers and
storms overnight through the day on Wednesday. A stationary
boundary sets up southwest to northeast across our area
overnight with light or even northerly winds to the north and
southerly winds south. As the remnants of Polo approach from
the southwest we see increased WAA along the strengthening warm
conveyor belt overnight. This will lead to some elevated
instability over the surface stable layer potentially allowing
for some heavier showers or even thunderstorms overnight across
southeast Nebraska into southwest Iowa. CAMs depict this pretty
well as a band of storms really ramping up between 1-3 AM and
exiting east of our area towards 7AM. Rainfall rates under
heavier storms could lead to some localized flash flooding early
Wednesday, especially in towns with more pavement.

We`re likely to see at least a short break Wednesday morning
after 8AM before the next round starts to push into southeast
Nebraska around 11AM. This will be associated with the
isentropic upglide north of the warm front from Polo interacting
with another weak shortwave moving across eastern Nebraska.

The round I`m most concerned about for heavy rain and
flash/river flooding arrives Wednesday night as we see Polo move
into north-central Kansas injecting additional moisture into the
region with a band of mid-level 850-700-mb frontogenesis setting
up across southeast Nebraska into southwest Iowa overnight into
early Thursday. This could further enhance rainfall rates with a
swath of 1-3 inches of rain likely just overnight across a good
portion of southeast Nebraska and southwest Iowa. Locally
higher amounts very possible. This all falling on already
saturated ground from previous rounds of rain will mean most of
this will end up as runoff into local rivers and creeks. Flash
flooding will be the immediate concern overnight, but flooding
on the bigger creeks and rivers will be likely through the day
on Thursday, possibly even lingering into Friday depending on
how long it takes to completely flush through our system.

Though still potentially heavy through Thursday morning, rain
should taper off through the afternoon on Thursday, clearing out
by the evening. Behind this system, a Canadian High slides down
over the Northern Plains keeping cooler air in place going into
the weekend with dry, quiet weather. Highs over the weekend stay
in the lower to mid-60s, with a reinforcing dry cold front
bringing another shot of cooler air in on Sunday.

The upper-level pattern quiets down going into next week with a
ridge building along the West Coast and broad high pressure
centered over the Great Lakes forcing the moisture axis from the
Gulf west of our area. I`d expect the transition to
northwesterly flow across our region to start bringing in more
shower/storm chances toward the latter half of next week once we
can bring the moisture plume back east over our area. While
weather stays quiet we do see temperatures trend back up into
the low-to-mid 70s toward midweek next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1225 AM CDT Wed Sep 30 2026

Another band of showers and some isolated storms are observed
southwest of the KLNK terminal this morning. Should see
activity track northeast with -SHRA overspread KLNK and KOMA in
the next few hours. Ceilings with this activity will drop to
LIFR at times while visibilities remain in MVFR. At KOFK, fog
development remains high (50-70% chance) after 07z and should
result in LIFR ceilings and visibilities. Fog burns off in the
late morning hours. After a brief 1-3 hr window of minimal
shower coverage, will see another band of rainfall move in from
south to north after 16z and last for the duration of the TAF
period. This activity will result in more IFR ceilings and
visibility restrictions at terminals. Southerly winds remain
under 10 kts during the TAF cycle, becoming northeasterly by
this afternoon.

&&

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

&&

$$

DISCUSSION...McCoy
AVIATION...Castillo