Flash Flood Warning 4, NWS Omaha, NE

Area Forecast Discussion
National Weather Service Omaha/Valley NE
537 PM CDT Sat May 16 2026

.KEY MESSAGES...

- Strong to severe storm chances expected for the afternoon
  (30%) and evening hours, with more storms possible in the late
  evening and overnight (70-90%).

- Continued threat for severe storms Sunday and Monday with all
  hazards possible.

- Temperatures cool down for Tuesday through Thursday in the 50s
  and 60s, warming back up toward the end of the week.

&&

.DISCUSSION...
Issued at 138 PM CDT Sat May 16 2026

Satellite gives a good idea of where the upper-level warm front
is located this afternoon, with partly cloudy skies along and
north of the boundary from Lincoln to Plattsmouth. Skies to the
south are mostly clear. We have the surface front to the south,
closer to the Kansas-Nebraska state line. We're going to be
watching this surface front push north into southeast Nebraska
over the next few hours, with an isolated storm or two possibly
developing later this afternoon. The upper-level shortwave
pushes into north-central Kansas around 7pm this evening,
kicking off storms in northeastern Kansas. A line of these
storms will move north into southeast Nebraska around 8-9pm
getting into Lincoln/Omaha around 10-11pm. This line of storms
will lift into northeast Nebraska after midnight. The second
round of storms develop near the Nebraska Panhandle this evening
and develop into a bowing line that will push into our area
around 1-2AM. Significant wind threat with this line of storms,
with potential for 70+ mph winds.

Sunday will start off with lingering cooler and cloudy
conditions from the overnight storms. It's going to take some
time for our environment to recover, with clouds maybe not
burning off until early afternoon. The developing surface low
has trended farther north, deepening which will strengthen the
surface pressure gradient across our area. Because of this
we'll see stronger winds develop out of the south, with gusts 35
to 45 mph expected starting mid-morning through the afternoon.
The first storms will develop either over northeast Nebraska or
southeast South Dakota around 6pm. CAPE values of around 3500
J/kg pooling along the warm front as well as 0-6km bulk shear
values of 35-40 kt should support discrete supercells
initially. Later in the evening closer to 9pm the low-level jet
intensifies, bringing stronger winds at 850mb into southeast
Nebraska. This should light up storms all along the cold front
from around Red Cloud northeast through Columbus and Thurston.
500-mb winds show steering flow pushing these storms east off
the frontal boundary. the best low-level shear will be over
northeast Nebraska into southeast South Dakota and northwest
Iowa Sunday evening, lending to the greatest potential for
embedded supercells and strong tornadoes in this area. However,
there will still be enough shear for a few supercells farther
south along the line of storms after 9pm for a tornado or two to
develop as far south as I-80. This line of strong to severe
storms clears east of our area by around 3-4am.

While the storms moved off to the east, the front does not
follow, staying put across our area into Monday acting as a
focus for more strong-to-severe storms on Monday. There are
differences in the CAMs on where exactly the front will be
Monday morning, with the HRRR keeping it just north of the
Omaha-Lincoln metros. Other hi-res models have it farther south,
closer to Nebraska City. It's location will greatly influence
the areas with severe weather potential on Monday. Storms are
expected to develop initially over north-central Kansas
potentially during the early afternoon, moving into southeast
Nebraska mid-afternoon into the early evening. All modes of
severe weather will again be possible, with tornadoes, large
hail, damaging winds, and flash flooding. These storms should
clear out of our area by 10-11pm.

Tuesday and beyond we finally get a break! The front shifts
south pushing the severe threat south and east of our area and
bringing in a cooler Canadian air mass for mid-week next week.
Tuesday will be much cooler with highs in the mid 50s to mid 60s
across our area, with highs moderating back up to solidly in the
mid 60s on Wednesday. Our next chances for rain hold off until
later next week with temperatures warming back up toward next
weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 537 PM CDT Sat May 16 2026

Storms have developed in southwest Iowa and central Nebraska.
Watching for this line to potentially fill in impacting KLNK,
but confidence in timing is low (30%). Better chance for storms
to impact KLNK and KOMA later this evening starting with a surge
of development northward into these two terminals around
03-04Z. This line of storms will hang over the the terminals
until a north-south line of storms moves in from the west around
06-07Z. KOFK remains north of the warm front and may not see any
storms until the north-south line arrives closer to 07Z (only a
60% chance storms impact KOFK). Once the storms clear east, MVFR
cigs appear likely to develop over northeast Nebraska impacting
KOFK primarily. A 40% chance low stratus makes it as far south
as KOMA. Clouds will be slow to clear Sunday, clearing around
17-18Z. Additional storms likely starting Sunday afternoon, but
may only see an isolated storm or two until chances increase
around 00Z.

Winds will remain out of the east this evening, shifting to the
southeast Sunday morning, then more southerly toward the
afternoon. Expect strong winds on Sunday (not generated by
storms) with gusts 25-35kt. A few gusts 40kt+ possible.

&&

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

&&

DISCUSSION...McCoy
AVIATION...McCoy

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
140 PM CDT Sat May 16 2026

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-171845-
Monona-Harrison-Shelby-Pottawattamie-Mills-Montgomery-Fremont-Page-
Knox-Cedar-Thurston-Antelope-Pierce-Wayne-Boone-Madison-Stanton-
Cuming-Burt-Platte-Colfax-Dodge-Washington-Butler-Saunders-Douglas-
Sarpy-Seward-Lancaster-Cass-Otoe-Saline-Jefferson-Gage-Johnson-
Nemaha-Pawnee-Richardson-
140 PM CDT Sat May 16 2026

This Hazardous Weather Outlook is for southwest Iowa, west central
Iowa, east central Nebraska, northeast Nebraska and southeast
Nebraska.

.DAY ONE...This afternoon and tonight.

Strong to severe thunderstorms may develop across the area/move into
the area after 4 PM (30% chance), with a better chance for storms
after 9 PM (70-90%). Strong winds (75+ mph) large hail, and tornadoes
will be possible, with tornadoes more of a threat through the
afternoon and evening, and wind a greater threat overnight.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Repeated rounds of showers and storms are forecast Sunday and
Monday -- primarily during the afternoon and evening hours. Large
hail and damaging winds, and tornadoes (some possibly strong) are
all possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time, but reports of
severe weather are appreciated.

Preliminary Local Storm Report
National Weather Service Omaha/Valley NE
515 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0512 PM     Hail             Red Oak                 41.01N 95.22W
05/16/2026  M1.00 Inch       Montgomery         IA   Amateur Radio

&&

Preliminary Local Storm Report
National Weather Service Omaha/Valley NE
517 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0515 PM     Hail             Red Oak                 41.01N 95.23W
05/16/2026  E1.00 Inch       Montgomery         IA   Public

            Report from mPING: Quarter (1.00 in.).

&&

Preliminary Local Storm Report
National Weather Service Omaha/Valley NE
519 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0516 PM     Hail             1 WSW Red Oak           41.00N 95.24W
05/16/2026  M1.75 Inch       Montgomery         IA   Emergency Mngr

            Emergency manager reports golf ball size
            hail just outside of Red Oak to the
            southwest.

&&

Preliminary Local Storm Report
National Weather Service Omaha/Valley NE
532 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0516 PM     Hail             3 S Red Oak             40.97N 95.23W
05/16/2026  M2.75 Inch       Montgomery         IA   Public

            Report from mPING: Baseball (2.75 in.).

&&

Preliminary Local Storm Report
National Weather Service Omaha/Valley NE
541 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0524 PM     Hail             3 ESE Red Oak           41.00N 95.17W
05/16/2026  M2.00 Inch       Montgomery         IA   Storm Chaser

            Storm chaser shared photos of measured two
            inch hailstones.

&&

Preliminary Local Storm Report
National Weather Service Omaha/Valley NE
552 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 PM     Tstm Wnd Gst     3 N Villisca            40.98N 94.98W
05/16/2026  M64 MPH          Montgomery         IA   Mesonet

            IA DOT station.

&&