Forecast Discussion
NWS Omaha/Valley, NE

124
FXUS63 KOAX 172337
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
637 PM CDT Sun May 17 2026

.KEY MESSAGES...

- Sunday and Monday will be days to watch very closely if you
  live within the Omaha area of forecast responsibility.
  Multiple rounds of severe thunderstorms are expected bringing
  the potential for large hail, damaging winds, tornadoes and
  flash flooding.

&&

.DISCUSSION...
Issued at 142 PM CDT Sun May 17 2026

This afternoon, an elongated sfc low will be in place from SE
Colorado/SW Kansas up into the Dakotas. A dryline is set up toward
the KS/CO border and a warm front is located across central
Nebraska. Temps are currently in the 80s in the warm sector with
dewpoints in the mid-60s. SBCAPE values of 3500+ J/kg, MLCAPE values
of 3000+ J/kg and DCAPE values of 1200+ J/kg are expected. Expect
good instability through the afternoon/evening and fairly steep
lapse rates, particularly down into central and eastern Nebraska.

Portions of northeastern Nebraska in particular are showing
potential for an environment favorable for strong updrafts and
potentially some longer lived supercells. Any storms that are able
to get going and become sustained in that favorable environment
would have the best chance of developing a tornado, with some
potential to be strong. Storms are expected to develop into a line,
posing a damaging wind threat along with hail and tornadoes
possible.

Heading into Monday, a broad trough extends from the PACNW up into
eastern Nebraska/western Iowa. Another system moves in through the
day, bringing additional chances for strong to severe storms,
particularly for areas along and south of Interstate 80. There still
remain some questions as to how far north the warm front and system
get. The environment is expected to be primed with strong
instability and deep layer shear conducive for supercell development
and maintenance. With this type of set up, large hail and damaging
winds are to be expected in addition to the possibility for a few
strong and potentially long-lived tornadoes. Flash flooding will be
possible, particularly in areas that have also received a few inches
of rain over the last 48 hours.

Expect cooler temperatures for much of the week as a cold front
pushes into the region Monday. Tuesday and Wednesday bring relief
from the recent storms.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 637 PM CDT Sun May 17 2026

A line of severe thunderstorms is observed at this hour from
near KOFK to KJYR to KHJH. These storms have a history of
producing large hail, damaging winds, and tornadoes. The line
will continue progressing eastward this evening, eventually
turning into more of a damaging wind threat as it approaches
KOMA and KLNK. Have continued mentions of -TSRA at terminals
this evening, refining timing at KOMA with the line expected to
arrive by 01z per latest model guidance. Expect frequent updates
and amendments. Background winds will switch to the west
northwest once the line moves through, and remaining at 12 kts
or less after 06z. Ceilings will deteriorate to MVFR and IFR at
terminals tonight behind the line of storms and persist through
much of the TAF cycle. After 20z, will see more redevelopment of
showers and thunderstorms, with chances over 50% late in the
TAF period. These storms will once again become strong to severe
with all hazards possible.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Flood Watch through Tuesday morning for NEZ065-066-068-078-
     088>093.
IA...None.

&&

$$

DISCUSSION...ANW
AVIATION...Castillo

NWS OAX Office Area Forecast Discussion

Forecast Discussion
NWS Hastings, NE

445
FXUS63 KGID 172348
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
648 PM CDT Sun May 17 2026

.KEY MESSAGES...

- Severe weather is likely this afternoon and evening, mainly in
  areas along/east of Highway 281. All severe threats are
  possible (large hail, damaging wind, and a few tornadoes),
  mainly in the 5pm-10pm window.

- Portions of northern Kansas and perhaps the Highway 81
  corridor in Nebraska have one more chance for severe storms on
  Monday afternoon. The rest of the area will be noticably
  cooler with only a few showers expected.

- Cooler-than-normal conditions are expected through midweek.
  Then we gradually trend warmer (with more rain chances) late
  in the week.

&&

.DISCUSSION...
Issued at 1235 PM CDT Sun May 17 2026

The main concern in this forecast revolves around severe
convection today and on Monday.

Currently, most of the area is in the warm sector, with a cold
front pushing in from the west, and a dryline/triple-point
expected to push in from the southwest this afternoon. The
eastern half of the area should be quite unstable by late
afternoon, the MLCAPE values likely in the 2000-4000 J/kg range.
If anything, CAMs have trended a bit further west with storm
initiation...possibly as early as 4pm...but becoming more likely
by around 5pm in the Highway 281 corridor. Strong deep-layer
shear will be supportive of supercells, potentially merging into
multiple line segments later into the evening hours. Confidence
in coverage is highest in northern parts of the area and
southern portions of the area, areas to the south and east of
Hastings may not

Generally the entire area near/east of Highway 281 has some
threat for tornado today, although the highest risk is expected
to be north and east of Grand Island where low-level shear is
maximized. Sig-tor parameter (STP) values of 5-7+ are forecast
by the RAP/mesoanalysis, which is a quite substantial indicator
of tornado potential.

A storm or two may approach western areas later this evening,
but are expected to weaken as the move into the area in the
8-10pm timeframe. Most of our Nebraska counties should be
storm-free by 8-9pm, but southern portions of the area have
potential for a longer-duration event, with storms continuing
to build near and just north of I-70. If this occurs, localized
flooding is possible (mainly Mitchell/Osborne counties),
although this will depend exactly on where storms setup.

Monday will start off cloudy and relatively cool, with
potentially some showers/drizzle in the morning and early
afternoon. An additional round of convection is expected to
develop along the stalled front. Less of the area is expected to
be impacted than today and Saturday, but nevertheless, portions
of northern KS, along with the Hwy 81 corridor could see severe
storms in the 3-8pm timeframe.

A Red Flag Warning remains in effect until 9pm today for
southwestern zones that are expected to see a quick burst of dry
air behind the dryline this afternoon. After today, the overall
fire weather threat is relatively low for the rest of this
week.

Not much time was spent on the longer-range forecast. Temperatures
remain below-normal through midweek, then gradually warm back
up into the Memorial Day weekend. Rain/t-storm chances also
return to the forecast by the end of next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 648 PM CDT Sun May 17 2026

For KGRI/KEAR Airports:

The threat for severe thunderstorms has shifted east of KEAR and
KGRI, although lightning will remain in the vicinity of KGRI for
another hour or so. VFR conditions are expected this evening,
with ceilings falling to MVFR and eventually IFR late tonight
through Monday morning. Ceilings could lift back to MVFR Monday
afternoon, but at least MVFR should prevail through the rest of
the forecast period. Light rain showers or drizzle could also
fall Monday morning. Winds are expected to remain northerly
through the forecast period. Gusty winds this evening should
settle at around 10-15 kts overnight through Monday morning,
then become gusty again Monday afternoon.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Red Flag Warning until 9 PM CDT this evening for NEZ083-084.
KS...Red Flag Warning until 9 PM CDT this evening for KSZ005-006-
     017-018.

&&

$$

DISCUSSION...Mangels
AVIATION...NWS Bismarck

NWS GID Office Area Forecast Discussion