Severe Thunderstorm Warning 365, NWS North Platte, NE

Area Forecast Discussion
National Weather Service North Platte NE
220 PM CDT Thu Aug 20 2026

.KEY MESSAGES...

- Strong to severe thunderstorms are possible, both this afternoon/evening
  and again early Friday morning for portions of central
  Nebraska with large hail, damaging winds, and heavy rain the
  main concerns.

- Additional strong to severe thunderstorms are possible Friday
  for portions of central Nebraska, though how morning activity
  affects later development casts some uncertainty.

- After a brief period of above normal temperatures tomorrow
  through the weekend, persistent active weather appears
  probable next week and should lead to daily rain/thunderstorm
  chances and more seasonable temperatures.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 220 PM CDT Thu Aug 20 2026

Early this afternoon, skies remained largely clear across the
region. Winds were largely out of the southwest around 10 to 15 mph
as temperatures climbed into the upper 70s to middle 80s. A subtle
wind shift continues to settle south through South Dakota towards
the Nebraska state line. This is largely occurring with little
change to sensible weather. That should change later this
afternoon/evening with details pertaining to this below.

This afternoon/this evening...modest high pressure drifts across
southern Canada and is propelling a wind shift line south through
South Dakota with gradual encroachment into western Nebraska through
the daytime. General south-southwesterly flow ahead of this is
helping sustain rich low-level moisture as dew points climb into the
60s. Aloft, broad upper ridging remains anchored over the Great
Basin and helping introduce a stout EML across the High Plains. As
afternoon temperatures reach the 80s, moderate to strong
destabilization will set up with various short-term solutions
depicting 1500-2500 j/kg of MLCAPE along a narrow corridor ahead of
the approaching wind shift line. Southerly surface flow beneath
moderate mid-level flow around 25 to 35 knots will promote an
adequately sheared environment with 0-6km BWD values of 30+ knots.
This will be more than enough to support storm organization within
ample instability/steep lapse rates aloft and lead to the potential
for strong to severe thunderstorms. The Storm Prediction Center
maintains a Slight Risk designation (level 2 of 5) which closely
aligns with the narrow corridor of greater instability previously
mentioned and have no qualms with this. While many ingredients are
in place to support a potential severe event, one uncertainty
remains and that focuses on storm coverage. Mesoanalysis data
suggests capping will likely linger through the day and with weak
forcing in place, may stymie development as a result. Current 18z
RAOB data from KLBF suggests capping closely aligns with the
mesoanalysis data and short-term CAM guidance fails to fully erode
this. This may lead to only isolated convection, perhaps widely
scattered at best, and limit the scope of the event as a result.
Still though, shear profiles showing long, straight hodographs
suggest splitting supercells with very large hail up to 2" possible
and damaging wind gusts around 70 mph the main concerns. Moderate
low-level helicity, namely in the 0-1km layer, could support a
tornado threat as well but confidence in this is low. Expect
convection to develop by late afternoon with a southeast motion.
Activity may struggle to sustain itself into the evening with the
loss of daytime heating and drier air becoming entrained into the
mid-levels leading to a fairly rapid decrease in available
instability.

Friday/Friday Night...Confidence is beginning to increase in at
least an isolated thunderstorm threat early Friday morning across
portions of central Nebraska. Should storms develop, strong to
severe hazards will be in play. A southwesterly developing low-level
jet tonight will arc anti-cyclonically with due westerly winds
pointed into north central Nebraska. While convergence/confluence
will be largely lacking, warm air advection will be reasonably
strong. Instability aloft will be strong, rooted around h7 with
around 1500-2000 j/kg CAPE as h7-h5 lapse rates near 6.5-7.5 C/km.
Within this layer of elevated instability, long/straight hodographs
with 25+ knots of BWD support additional strong to severe
thunderstorms. With forcing tied to winds aloft, parcels should be
largely uninhibited. What does cause some uncertainty is being on
the east periphery of the more impressive EML and whether the weaker
lapse rates play a role in storm strength. Either way, believe some
severe mention is worthy at this point with only isolated coverage
appearing likely. Through the day Friday, how the atmosphere
recovers from any morning activity will play a large role in the
severe potential later in the day. Residual clouds and any lingering
outflow may hinder afternoon temperatures slightly and this may
result in more stable conditions across our east. Precise details
may be murky at best until we see coverage of any early morning
development. Regardless, with the influence of a strong EML aloft
above warm and humid conditions, severe thunderstorms will again be
possible. The SPC highlights much of the region with a Slight Risk
(level 2 of 5) for Friday. Increased influence of a mid-level speed
max will promote a stronger sheared environment across the area with
strong instability in place to the tune of 2500-3500 j/kg MLCAPE.
Large hail and damaging winds, potentially significantly severe (2"+
or 75+ mph respectively) will be possible with any thunderstorms
that form. High storm bases with highs reaching the 90s should limit
any tornado threat though should any outflow boundary settle in the
area, this concern could increase in vicinity of this feature. HREF
highlights increased QPF probabilities during the typical late
summer window, late afternoon through the evening, and see no reason
to stray from that thus PoPs align with this idea. While widespread
wetting rains are not anticipated, the NBM does highlight portions
of the local area around a 40% chance of seeing 0.25" or greater
rainfall. This is likely to remain spotty though. Thunderstorms may
be slow to depart the area, but should do so prior to dawn on
Saturday.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 220 PM CDT Thu Aug 20 2026

Upper level ridging will amplify by early weekend with the ridge
axis approaching from the west. Broad upper troughing will remain
stalled out across the Hudson Bay with a second disturbance lifting
into the Pacific Northwest. This should result in ridge breakdown as
a lead shortwave ejects out of Wyoming. The result of this will be
increased rain and thunderstorms again, favoring late Saturday into
Sunday. Flow will generally flatten out as this Pacific Northwest
disturbance begins to translate across southern Canada by early
next week. A trailing frontal boundary with reinforcing high
pressure should traverse the area towards the middle of the week.
This will sustain daily rain and thunderstorm chances while keeping
temperatures more on the seasonable side (average highs for late
August are low to middle 80s). Should this pattern hold, recurring
rain chances will bring about potential for at least locally
beneficial rainfall to some drought stricken areas. Details remain
far from certain so continue to check back with later forecasts.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1214 PM CDT Thu Aug 20 2026

Early morning fog/low stratus have cleared, leaving largely
clear skies early this afternoon.

This is likely to persist until a weak frontal boundary settles
further south and serves as the focus for thunderstorm
development later this afternoon/evening. This will likely split
the LBF/VTN terminals while remaining to the east thus have no
direct impacts mentioned at either site. Periodic mid-level
cloudiness should envelope the VTN vicinity but is expected to
remain in the low-end VFR range. Will need to monitor potential
for any earlier or further west development of thunderstorms,
as subtly hinted at by recent HRRR runs, for later inclusion.
For now, confidence remains low in this occurring.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.

&&

SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...NMJ

Hazardous Weather Outlook
National Weather Service North Platte NE
307 PM CDT Thu Aug 20 2026

NEZ004>010-022>029-035>038-056>059-069>071-094-212015-
Sheridan-Eastern Cherry-Keya Paha-Boyd-Brown-Rock-Holt-Garden-Grant-
Hooker-Thomas-Blaine-Loup-Garfield-Wheeler-Arthur-McPherson-Logan-
Custer-Deuel-Keith-Perkins-Lincoln-Chase-Hayes-Frontier-
Western Cherry-
307 PM CDT Thu Aug 20 2026 /207 PM MDT Thu Aug 20 2026/

This Hazardous Weather Outlook is for portions of western and north
central Nebraska.

.DAY ONE...This afternoon and tonight.

Isolated to widely scattered thunderstorms remain possible through
this evening, mainly for areas along and east of Highway 83 and north
of Highway 2. Any storms that form will pose a risk for large to
very large hail, damaging winds, and locally heavy rainfall.

Renewed thunderstorm development is possible in the predawn hours
Friday, mainly for portions of central Nebraska. Should activity
develop, a few could be strong to severe with large hail, damaging
winds, and locally heavy rainfall the main concerns.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Isolated to scattered thunderstorms chances return Friday
afternoon/evening across western and north central Nebraska.
Confidence in precise evolution of the thunderstorm threat is limited
as morning activity may hamper the afternoon environment. Should
the environment recover and storms develop, strong to severe storms
will again be possible with large to very large hail and damaging
winds the primary threats. The main area of concern is generally
east of Highway 61. Continue to monitor later forecasts for up to
date thinking on the concern.

Thunderstorms will continue to be possible daily from Saturday
through Wednesday. At this time, the severe threat is uncertain.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed.

Special Weather Statement
National Weather Service North Platte NE
302 PM CDT Thu Aug 20 2026

NEZ005-008-202030-
Brown NE-Eastern Cherry NE-
302 PM CDT Thu Aug 20 2026

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL CHERRY AND WEST
CENTRAL BROWN COUNTIES THROUGH 330 PM CDT...

At 302 PM CDT, Doppler radar was tracking a strong thunderstorm 12
miles west of Johnstown, or 22 miles southeast of Valentine, moving
southeast at 20 mph.

HAZARD...Wind gusts up to 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Wood Lake.

This includes Highway 20 between mile markers 214 and 225.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4266 10043 4271 10034 4253 10004 4242 10025
TIME...MOT...LOC 2002Z 321DEG 19KT 4261 10030

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

NWS LBF

Special Weather Statement
National Weather Service North Platte NE
329 PM CDT Thu Aug 20 2026

NEZ005-008-202100-
Brown NE-Eastern Cherry NE-
329 PM CDT Thu Aug 20 2026

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL CHERRY AND WEST
CENTRAL BROWN COUNTIES THROUGH 400 PM CDT...

At 329 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles west of Johnstown, or 18 miles west of Ainsworth, moving
southeast at 20 mph.

HAZARD...Wind gusts up to 40 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Johnstown.

This includes Highway 20 between mile markers 222 and 237.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4259 10032 4265 10020 4256 9995 4242 10020
TIME...MOT...LOC 2029Z 318DEG 14KT 4257 10021

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

NWS LBF