MD 0703 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PARTS OF CENTRAL THROUGH NORTHEASTERN NEBRASKA INTO WESTERN IOWA
Mesoscale Discussion 0703
NWS Storm Prediction Center Norman OK
0451 AM CDT Sun May 07 2023
Areas affected...parts of central through northeastern Nebraska into
western Iowa
Concerning...Severe potential...Watch unlikely
Valid 070951Z - 071215Z
Probability of Watch Issuance...20 percent
SUMMARY...Strong thunderstorm development, perhaps including an
organizing cluster, may continue to pose at least some risk for
severe weather into and beyond daybreak. It is not clear that a
severe weather watch will be needed, but trends will continue to be
monitored for this possibility.
DISCUSSION...Thunderstorm activity (currently near Broken Bow
through areas west and northeast of Norfolk) has probably been
producing some severe hail while intensifying and gradually growing
upscale the past hour or two. This appears to be focused within a
zone of enhanced mid-level warm advection, on the northern periphery
of a plume of warm and capping elevated mixed-layer air. Given the
steep lapse rates aloft, elevated moisture return may be
contributing to moderately large CAPE, in the presence of strong
cloud-bearing layer shear.
It is possible that the forcing for ascent could contribute to the
evolution of a small organizing cluster across the Sioux City area
through daybreak, with additional thunderstorm development
downstream, to the southeast, across western Iowa. Despite the
presence of a sizable sub-cloud layer with warm temperatures and
large temperature/dew point spreads, weak ambient flow through this
layer, coupled with at least a shallow relatively cool near-surface
layer, may tend to minimize the risk for the development of strong
surface gusts.
..Kerr/Grams.. 05/07/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DMX...FSD...OAX...GID...LBF...
LAT...LON 42159817 42539612 41759400 40749498 41239676 41139829
41529908 42159817
