Hail and Damaging Winds in Nebraska, May 15, 2026

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1226 PM CDT Fri May 15 2026

.KEY MESSAGES...

- Showers and storms likely this evening (60-80% chance).
  Storms may be severe with large hail and damaging winds.

- Additional rounds of strong to severe storms possible Saturday
  through Monday with large hail, damaging winds, tornadoes, and
  flash flooding all possible.

- Pattern quiets down Tuesday and beyond with highs in the 60s
  Tuesday and Wednesday, warming into the 70s later in the week.

&&

.DISCUSSION...
Issued at 1226 PM CDT Fri May 15 2026

Clear skies this morning with some scattered cu starting to
develop over south-central Nebraska. Water vapor satellite
imagery shows the deepening trough over the West Coast which
will lead to the development of our active pattern going into
the weekend. Over eastern Nebraska, RAP objective analysis shows
a front situated along the western extent of our area, from a
few miles east of Yankton south to around Hastings. This
boundary will continue to slowly move southeast, eventually
stalling from around Onawa, IA southwest to around Red Cloud,
NE. This corridor will be the focus for initial storm
development as the upper-level wave arrives this evening.

Temperatures are forecast to get very warm today, with highs in
the 90s. In northeast Nebraska, we will again expect humidity to
drop to 20 to 25 percent this afternoon leading to very high
fire danger. Fairly weak winds of 5 to 10 mph should limit Red
Flag conditions.

Through the afternoon we'll start to see moisture pooling along
the surface front with an upper-level shortwave kicking off
storm development around 6-7pm this evening. We're expecting
2000-2500 J/kg of SBCAPE to develop, combined with 0-6 km of
bulk-shear of 35 to 40 kt should favor supercell development
initially. Dry low-levels in the soundings indicate high-base
hailers initially evolving into a damaging wind threat as storms
converge into clusters or more into a line. The tornado threat
at this time is very low due to high LCLs along with little low-
level curvature in the hodograph, but SPC has bumped a good
portion of our west-central Iowa counties up into an Enhanced
Risk (level 3 of 5) for increased damaging wind and hail threat.

As previously mentioned, storms should initially develop along
the northeast to southwest frontal boundary which will stall
across our area this afternoon. The general consensus of the
CAMs suggest that these storms will congeal into clusters or a
line and move southeast through the evening, clearing out by
around midnight-2am. With increased confidence in placement of
these storms, have increased PoPs to around 60-80 percent this
evening in areas with the greatest chance of seeing storms.

Saturday will be another warm day, though a few degrees cooler
due to starting out the day with the post-frontal air mass in
place across our area. With the approach of our next upper-level
wave, we'll see a warm front lift back north into our area
through the afternoon. CAM guidance is still not confident in
any convection developing along this front during the late
afternoon into the evening. The HRRR and RRFS, though, (both
notorious for over- convecting at times) give us at least an
idea of what it may look like if we get storms along this front.
3000-3500 J/kg of MLCAPE develop along and south of the warm
front with 40-50 kt of bulk shear. If storms develop, they'd
likely be severe developing into discrete supercells initially,
congealing into a east-west line with potential for large hail,
damaging winds, a tornado or two, and flash flooding. Over
western Nebraska an upper-level wave will kick off convection
during the afternoon, developing into a few different segments
of storm clusters that travel eastward across the state through
the evening. These segments grow into bowing segments tracking
eastward into our area by late evening with a damaging wind and
hail threat persisting through around 3-5am as they move across
our area.

Sunday's severe potential may at least initially be greatly
impacted by any lingering showers, storms, and cloud cover from
the early morning system. As H5 troughing deepens over the
Intermountain West, we'll see a strong low-level jet set up,
nosing into eastern Nebraska and western Iowa during the
afternoon. This will help to bring in more low-level moisture.
Surface winds could get fairly strong on Sunday, gusting 35 to
45 mph out of the south, enhancing low-level shear. Instability
of 3000-4000 J/kg combined with 40-45 kt of bulk shear should
support supercells as the cap erodes during the afternoon. With
greater low-level moisture and shear, all modes of severe
weather will be possible including large hail, damaging winds,
flash flooding, and tornadoes.

Monday will have a similar set-up as the H5 longwave trough
nudges eastward, closer to our area, with similar values of
instability and perhaps even more shear expected to develop. The
area of greatest threat on Monday will be a bit farther east
than Sunday, more directly across eastern Nebraska and western
Iowa.

The rest of the week next week looks quiet with cooler
temperatures moving in on Tuesday and Wednesday (highs in the
60s). Temperatures trend back upward later in the week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1226 PM CDT Fri May 15 2026

VFR conditions this afternoon with storms forecasted to develop
around 00Z this evening just northwest of KOMA and KLNK. Expect
storms to impact the terminals from around 01-03Z with potential
for large hail and damaging winds. Cloud bases should be fairly
high, around 6000-8000 ft with any storms. Once storms clear,
winds will shift to the north or northeast, becoming more
easterly toward daybreak on Saturday. We'll see winds increasing
out of the east toward the end of the TAF period with additional
strong to severe storms possible Saturday evening into the
overnight hours.

&&

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

&&

DISCUSSION...McCoy
AVIATION...McCoy

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
219 PM CDT Fri May 15 2026

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-161930-
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-
219 PM CDT Fri May 15 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 storms are possible late this afternoon into the
evening and overnight hours. Damaging winds and hail are the primary
hazards.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Repeated rounds of showers and storms are forecast to continue into
early next week. There is severe weather potential during the
afternoon and evening each day through Monday. Large hail and
damaging winds are the main hazards, but isolated tornadoes can't be
ruled out.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed this afternoon or tonight.