MD 2178 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PARTS OF WESTERN THROUGH CENTRAL NEBRASKA
Mesoscale Discussion 2178
NWS Storm Prediction Center Norman OK
0227 AM CDT Sat Sep 23 2023
Areas affected…parts of western through central Nebraska
Concerning…Severe potential…Watch unlikely
Valid 230727Z – 231000Z
Probability of Watch Issuance…20 percent
SUMMARY…Intensifying thunderstorm development appears probable
within the next couple of hours, with the evolution of an organizing
cluster possible through 5-7 AM CDT. Stronger storms may be
accompanied by a risk for severe hail, at least initially. The risk
for severe surface gusts currently appears low, but trends will be
monitored.
DISCUSSION…Beneath the leading (northern) edge of a plume of warm
and capping elevated mixed-layer air advecting across the central
Great Plains, lower level warming and moistening is contributing to
substantive destabilization across southwestern through central
Nebraska. CAPE for most unstable parcels, within a saturating
environment rooted above a more stable near-surface layer, now
appears to be increasing in excess of 2000 J/kg, as an upstream
mid-level low gradually shifts across and east of the northern
Rockies.
Mid-level forcing for ascent and cooling, within the exit region of
a mid-level jet streak (50-60 kt around 500 mb) propagating
east-northeast of the Colorado Rockies, is forecast to overspread
much of western through central Nebraska and adjacent portions of
South Dakota by 09-12Z. As it does, it will likely overcome the
inhibition and support increasing convective development. Given the
potential instability, and strong shear within the cloud-bearing
layer, this probably will include convection capable of producing
severe hail, at least initially. Aided by lift associated with the
lower/mid-tropospheric warm advection, an organizing cluster may
gradually develop through daybreak. This could eventually be
accompanied by a developing MCV and strengthening rear inflow toward
daybreak. However, even if this occurs, the potential for damaging
gusts to reach the surface current appears low, due to the stable
near-surface layer.
..Kerr/Edwards.. 09/23/2023
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…FSD…GID…LBF…UNR…
LAT…LON 42680158 43580048 42729849 40549931 40700131 42050164
42680158
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