Mesoscale Discussion 2038
NWS Storm Prediction Center Norman OK
0901 AM CDT Wed Aug 19 2026
Areas affected...parts of central and eastern Nebraska
Concerning...Severe potential...Watch possible
Valid 191401Z - 191600Z
Probability of Watch Issuance...40 percent
SUMMARY...An isolated supercell structure, perhaps with some upscale
growth into a small organizing cluster, may be maintained at least
into the 11 AM-1 PM CDT time frame, posing a continuing risk for
large hail and locally strong to severe gusts while moving
south-southeastward. It is not yet certain that this will require a
severe weather watch, but trends are being monitored for this
possibility.
DISCUSSION...Downstream of a low amplitude short wave trough,
digging within broader cyclonic northwesterly mid-level flow, at
least a localized area of stronger forcing for ascent (largely
associated with warm advection centered near/below the 700 mb level)
is maintaining isolated vigorous convection now propagating slowly
southeastward to the west and southwest of O'Neill. Strong shear
within the convective layer is contributing to a sustained supercell
structure, which still appears rooted above a relatively cool/stable
near surface layer.
Based on forecast soundings, convection appears based around 850 mb,
where a narrow corridor of higher moisture content may be supporting
updraft inflow of air characterized by most unstable CAPE on the
order of 1500-2000 J/kg. It appears that this could be maintained
at least into the 17-18Z time frame, as the stronger forcing for
ascent develops south-southeastward toward the Columbus and Grand
Island vicinities.
..Kerr/Smith.. 08/19/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OAX...GID...LBF...
LAT...LON 42249883 42399849 41939743 41489698 40939724 41179803
41779905 42059923 42249883
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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