Mesoscale Discussion 2023
NWS Storm Prediction Center Norman OK
0608 AM CDT Tue Aug 22 2023
Areas affected…the northern Wisconsin/western Upper Michigan
Concerning…Severe potential…Watch unlikely
Valid 221108Z – 221315Z
Probability of Watch Issuance…20 percent
SUMMARY…A few storms across the northern Wisconsin and western
Upper Michigan vicinity over the next couple of hours may be capable
of producing hail in excess of 1″ in diameter. However, it is
expected that risk should remain sufficiently isolated so as not to
require WW issuance.
DISCUSSION…Latest radar loop across the Great Lakes region shows a
gradual increase in convective coverage, within a zone of warm
advection being supported by a 30 kt west-southwesterly low-level
jet. However, convection has remained limited in intensity thus
far, likely inhibited by a warm layer indicated in model soundings
near within the 850mb to 700mb layer.
With that said, a low-level jet extending across the Mid Missouri
and Upper Mississippi Valleys continues to advect higher theta-e
low-level air into the region, beneath rather steep mid-level lapse
rates. Additionally, potential for convective intensification will
be supported by veering/increasing flow through the cloud-bearing
layer, with 40 to 50 kt west-northwesterlies observed at mid levels.
This, along with the aforementioned thermodynamic support, suggests
potential for isolated occurrences of hail in excess of 1″ in
diameter with a few of the stronger storms. With that said, it is
expected that the anticipated, isolated nature of the risk will
preclude the need for WW issuance.
…Please see www.spc.noaa.gov for graphic product…
LAT…LON 47179252 47539220 46798891 45858689 44428763 45228953
46039234 46869265 47179252