Forecast Discussion
NWS Omaha/Valley, NE

126
FXUS63 KOAX 180457
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1157 PM CDT Sun May 17 2026

.KEY MESSAGES...

- Potential for more severe weather on Monday, mainly across
  southeast Nebraska and southwest Iowa. Large hail, damaging
  winds, strong tornadoes, and flash flooding will all be
  possible.

- Cooler weather moves in on Tuesday with potential for morning
  frost for northeast Nebraska on Wednesday.

- Another active pattern may set up going into next weekend with
  chances for more storms, and possibly severe weather.

&&

.DISCUSSION...
Issued at 1155 PM CDT Sun May 17 2026

The line of storms has cleared east of the area but much of
southeast Nebraska and southwest Iowa remain under the
stratiform rain shield with some embedded weak thunderstorms.
This likely won`t completely clear until closer to 7am Monday
morning. Going into Monday we`re going to be watching to see
where the cold front stalls, which will help determine our area
of potential severe weather Monday evening.

Monday will start out cloudy, with scattered light rain showers
across much of the area north and west of the cold front
stalled across our area. Through the late morning into the
afternoon we`ll see clouds gradually clear in areas south and
east of the cold front. Areas north of the cold front will stay
cloudy. The upper-level shortwave arrives, kicking off storm
initiation around 2-4PM. Storms that develop in the warm sector
will have ample instability and shear to grow into discrete
supercells with potential for large hail, damaging winds, and
strong tornadoes. Expect similar storm evolution, growing into a
QLCS with embedded supercells, which exits our area by 10PM.
Several CAMs show a second line of storms which develops around
8-9PM over our western counties and moves through potentially
bringing another chance for severe hail and damaging winds.
These storms will be elevated in nature, but may still have 1500
J/kg of elevated MUCAPE to work with. This second line clears by
midnight, bringing an end to the long, several day stretch of
severe weather.

We`ll see the cold front clear well to the south and east of our
area by Tuesday, putting a cooler Canadian air mass in place
across the region. Tuesday will start out cloudy once again, but
really clear by the afternoon as high pressure builds over our
area. High temperatures on Tuesday will only reach into the
upper 50s to mid 60s. With clear skies and nearly calm winds,
this lends to potential for frost early Wednesday. Overnight
lows will drop into the mid 30s for northeast Nebraska to low
40s across southeast Nebraska and southwest Iowa. Cooler weather
holds into Wednesday though we do see a reversal to southerly
winds and start to advect moisture back into the region. An
upper-level shortwave could potentially bring a few showers to
the area Wednesday afternoon and evening, but the ensembles
haven`t picked up on this latest change in the deterministic
guidance. In any case, this wouldn`t be anything impactful.

A better chance for showers and storms moves in Thursday as the
longwave trough that`s been nearly stationary over the western
US shifts eastward toward our area. With temperatures still in
the sixties for highs, I wouldn`t anticipate much of a severe
weather threat with this system for our area.

Temperatures start to rebound on Friday though as we see
enhanced warm air advection ahead of a deepening surface low
which develops on the lee side of the Rockies over eastern
Colorado and western Nebraska. Depending on the track of this
system, we could potentially see more active weather next
weekend with several chances for storms.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1156 PM CDT Sun May 17 2026

A line of storms continues to exit the region to the east late
this evening. North winds and low ceilings have overspread the
region behind these storms. OFK and LNK have fallen to MVFR with
OMA expected to fall over the next hour or two. Winds remain
out of the north tonight. A further reduction to IFR ceilings
appears likely at OFK around 9Z and at OMA and LNK closer to
13Z. Our next low pressure system will quickly lift northeast
out of the southern Great Plains during the afternoon. This is
anticipated to result in another round of widespread
thunderstorms. Severe thunderstorms are anticipated with large
hail, damaging winds, and a few tornadoes possible. Current
timing has storms in the vicinity of LNK between 21-23Z with OFK
and OMA following shortly after between approximately 22Z and
00Z. Very heavy rainfall will reduce visibility at times with
the potential for gusty and erratic winds also. A cold front
pushes through the region behind these storms. Gusty northwest
winds and MVFR ceilings develop as the cold front moves east
across the area.

&&

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

&&

$$

DISCUSSION...McCoy
AVIATION...Chehak

NWS OAX Office Area Forecast Discussion

Forecast Discussion
NWS Hastings, NE

594
FXUS63 KGID 180736
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
236 AM CDT Mon May 18 2026

.KEY MESSAGES...

- A handful of severe storms capable of producing large hail,
  damaging wind gusts or an isolated tornado will be possible
  between 3-8PM today. The severe threat will mainly be for
  places near and east of HWY-81.

- A few showers, areas of drizzle and non-severe thunderstorms
  will be possible later this morning to afternoon across areas
  outside of the severe threat.

- Highs, following the passage of a cold front today, will peak
  in the 50s and 60s for much of the area. A few north central
  Kansas locations as well as far southeast nebraska areas could
  see highs in the 70s.

- The next chance of precipitation will come Wednesday night
  (40-50% chance).

- Highs the rest of the week will stay in the 60s for
  Tuesday/Wednesday/Thursday, the low to mid 70s for Friday and
  the upper 70s to low 80s for Saturday.


&&

.UPDATE...
Issued at 235 AM CDT Mon May 18 2026


Today...

Severe storms will again be possible across a few of the same
locations that have observed severe weather across the past two days
(Primarily north central Kansas and Nebraska locations east of HWY-
81). A persisting trough that has stalled out across the
intermountain west region this past weekend will once more steer a
southwesterly jet overtop of the Central Plains today. A cold front
this morning resides across parts of central Kansas and eastern
Nebraska. This feature will become the day`s primary storm forcing
mechanism. The cooler and drier airmass behind the front should
dampen the severe weather potential for much of our northwest half
of the area including our central/Tri-Cities area (though showers
and weak storms may still be possible). Highs in response to the
gusty cool air advecting winds behind the front should also struggle
to break out of the 50s to low 60s beyond a few north central Kansas
and far southeast Nebraska locations.

As far as the storms go this afternoon (between 3-8PM), all
convective types will be possible with all hazards in the mix (large
hail, damaging winds, and a few tornadoes). A warm, moist and
unstable airmass ahead of the cold front will offer plenty of energy
to allow storms to erupt and quickly become severe (up to 1,500-
4,000J/kg of MUCAPE). Southerly winds ahead of the front and
underneath the southwesterly jet will provide enough shear for a few
supercells to spin, though the strong frontal forcing should prevent
storms from staying isolated for too long (squall/MCS will be
favored). With how far the cold front has advanced today, its is
unlikely for the severe storms to impact much of our local area
(mainly for areas near and east of HWY-81 and for a few north central
Kansas locations). Only a southeast sliver of the area (areas
southeast of a line from York, NE to Osborne, KS) has been included
in a slight (level 2 of 5) or enhanced (level 3 of 5) severe weather
outlook.

Though the severe storms are expected to mainly stay concentrated to
the southeast of most of the area, widespread drizzle, light rain
and some non-severe thunderstorms will still be possible for part of
the morning and afternoon hours today. Up to 0.5" of precipitation
may be possible.


Tuesday & Wednesday...

Cooler temperatures will take over on Tuesday and Wednesday
following the passage of the cold front today. Highs are forecast to
remain in the 60s with overnight lows in the 30s to low 40s. The
formation of frost may have to be monitored closely across a few
locations closer to the Nebraska sandhills Tuesday night as winds
look to calm overnight. These calming winds will be a result from
the high pressure center swooping in near the middle of the week.
The next chance for precipitation will not come until Wednesday
night (40-50% chance) as a weak shortwave disturbance potentially
comes pivoting out of the Rockies.


&&

.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 /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1226 AM CDT Mon May 18 2026

For KGRI/KEAR Airports:

At least Low-end MVFR ceilings are expected to dominate the 6z
TAF period as a low deck of broken to overcast stratus remains
lock in overhead. Ceiling will gradually lower through the
night, reaching high end IFR levels just after sunrise (12-14z).
KGRI may even drop into low-end IFR and LIFR between 16-20z.

A period of drizzle to light rain is expected to impact both
terminals between 14 and 19z. There is a low-end chance for a
thunderstorm to be in the KGRI vicinity between 22-2z.

Otherwise, winds will remain out of a northerly direction
through the day (340-030 degrees) with speeds sustaining near
15-20kts and gusting as high as 25-35kts.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.

&&

$$

UPDATE...Stump
DISCUSSION...Mangels
AVIATION...Stump

NWS GID Office Area Forecast Discussion