273
ACUS11 KWNS 300325
SWOMCD
SPC MCD 300325
NEZ000-SDZ000-300530-

Mesoscale Discussion 1391
NWS Storm Prediction Center Norman OK
1025 PM CDT Mon Jun 29 2026

Areas affected...portions of central and northeastern Nebraska

Concerning...Severe Thunderstorm Watch 418...

Valid 300325Z - 300530Z

The severe weather threat for Severe Thunderstorm Watch 418
continues.

SUMMARY...The potential for severe wind gusts (potentially including
significant gusts up to 75-90 mph) and large hail is expected to
expand northeastward over the next 1-2 hours.

DISCUSSION...Ongoing convection across Severe Thunderstorm Watch 218
has been slow to develop/organize thus far, but an uptick in
convective intensity has recently been noted across central Nebraska
over the past 30-60 minutes. This activity is occurring along the
northern periphery of a surface instability/theta-e gradient and at
the northern tip of a strengthening southerly, low-level jet sampled
by the UEX VWP. While latest high-res model guidance has somewhat
struggled with the overall placement of convection, guidance
continues to suggest that upscale growth into a compact, bowing
cluster/complex will occur as convection evolves (and potentially
accelerates northeastward) along the aforementioned gradient.

While uncertainty remains regarding the exact convective evolution
over the next 1-2 hours owing to the complexity of cell/convective
interactions, strong to extreme instability (MLCAPE of 4000-5000
J/kg indicated by latest objective analysis and the 00z OAX observed
sounding) along and southeast of this gradient coupled with strong
effective shear (50-60+ kts) and steep mid-level lapse rates would
favor an increasing severe threat in this scenario. Severe to
significant wind gusts up to 75-90 mph (perhaps locally greater in a
higher-end scenario) remain conditionally plausible pending the
organization of ongoing convection into an organized cluster. Large
hail also remains possible with any semi-discrete or embedded
supercell structures, with additional potential for wind-driven hail
to accompany any stronger cluster.

..Chalmers.. 06/30/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FSD...OAX...GID...LBF...

LAT...LON   41239886 41269914 41409943 41659942 41939927 42389866
            42649826 42769802 42889768 42919723 42779671 42579656
            42309649 42089666 41899692 41629743 41389811 41239886

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...75-90 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN