853
FXUS63 KOAX 290529
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1229 AM CDT Tue Sep 29 2026

.KEY MESSAGES...

- Widespread rainfall of 2 to 4 inches expected through
  Thursday, with locally higher amounts. 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 1051 PM CDT Mon Sep 28 2026

High clouds have spread across the area while lower clouds from
earlier have cleared. Winds are out of the southeast. Looking at
satellite we have a couple of main features that will aid in the
heavy rain forecast for the next couple of days. We see an
upper-level trough over the Great Basin and Sierra Nevadas, and
Hurricane Polo along the southern coast of Baja California.
Hurricane Polo will inject additional tropical moisture into
the warm conveyor belt ahead of the upper-level trough leading
to a significant amount of moisture advection into west Texas,
New Mexico, Colorado, Kansas, and Nebraska over the next couple
of days.

The first round of rain arrives tomorrow morning as the western
trough pushes eastward, shifting the warm conveyor belt into
eastern Nebraska. Expect a complex of showers with a few
embedded storms to push through south-central into northeast
Nebraska, perhaps all the way down to I-80. This will clear by
mid-morning but with strong isentropic upglide across the
region through the day, I`d expect to continue to see areas of
light rain continuing into the afternoon. The next round of
heavier rain will arrive tomorrow evening, this time more across
southeast Nebraska into southwest Iowa. A swath of 1-2 inches of
rain is expected with this round, looking more likely around
Beatrice to just north of Nebraska City.

Additional shortwaves will continue to bring periods of heavier
rainfall into Wednesday with heaviest rainfall expected
overnight Tuesday night and again Wednesday night. We`re
watching Wednesday night for some potential for severe storms.
Wednesday night we see the remnant surface low from Hurricane
Polo lift north across central Kansas into southeast Nebraska.
This will steepen lapse rates, increasing environmental
instability. We`ll also see fairly good low-level shear along
the warm front lifting north. Right now the greatest severe
potential is to our south with the surface warm front not quite
making it into southeast Nebraska, but if it does push farther
north, we could see potential for wind and tornadoes shift north
into our area.

Wednesday evening may be the time we see heaviest rainfall
northeast of the surface low. At this time we see strong
moisture advection overtop of the surface frontal boundary. PWAT
values around 2.1 to 2.2 inches is well in excess of our
climatological max of 1.72 inches for October 1st, or even most
of the month of September. Every deterministic model I bring up
shows 2.1 to 2.2 inches across much of eastern Nebraska into
western Iowa. This will create highly efficient rainfall with
ensemble guidance highlighting potential for a broad area of
1-2 inches of rain over a 6-hr period. This on top of already
saturated ground really increases the potential for river
flooding Wednesday night going into Thursday with lingering
river impacts potentially into Friday-Saturday on main-stem
rivers such as the Platte and Missouri (south of the Platte).

Rainfall clears off to the southeast Thursday as the upper-level
trough shears away with the cold front sinking south of our
area. Skies may clear Thursday night into early Friday
potentially leading to some significant widespread fog Friday
morning. Going into the weekend, we`re going to see a period of
quiet weather with a decaying ridge building over the region.
We`ll be glanced by the southern edge of a Canadian High keeping
temperatures on the cooler side Friday and Saturday. Saturday
night a dry cold front looks to move through bringing a
reinforcing surge of cooler air for early next week keeping
highs in the low-to-mid 60s and lows in the upper 40s to low
50s.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1229 AM CDT Tue Sep 29 2026

Broken to scattered clouds at 25,000 feet are observed over
most terminals this morning leading to VFR conditions. Will see
a band of rain showers overspread terminals within the next few
hours with ceilings largely staying VFR, and there could
be a few storms embedded (15-20% chance) but confidence on any
terminal seeing -TSRA remains too low for mentions. KOFK could
see some gustiness of 20-25 kts after 12z too. By the late
morning hours, will see a break in rain showers before a second
round approaches terminals in the afternoon leading to MVFR
ceilings and visibility reductions which last through the end
of the TAF cycle. Southeast winds become southerly by the
afternoon at 12 kts or less.

&&

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

&&

$$

DISCUSSION...McCoy
AVIATION...Castillo