SPC MD 1400

MD 1400 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WESTERN UP OF MICHIGAN AND LAKE SUPERIOR

Mesoscale Discussion 1400
NWS Storm Prediction Center Norman OK
1253 AM CDT Sat Sep 01 2018

Areas affected...Western UP of Michigan and Lake Superior

Concerning...Severe potential...Watch unlikely 

Valid 010553Z - 010800Z

Probability of Watch Issuance...5 percent

SUMMARY...A short-term threat for locally damaging wind and
marginally severe hail continues.

DISCUSSION...The fast-moving thunderstorm cluster currently
approaching the western UP of MI has been maintaining its intensity
within an environment characterized by moderate MLCAPE (1000-1500
J/kg) and effective shear of 30-40 kt. A relatively uncapped airmass
(for surface-based parcels) immediately downstream, characterized by
where surface temps remain near 70 F, should help to maintain this
cluster for the next 1-2 hours. Some potential remains for locally
damaging wind gusts, especially across the Keweenaw Peninsula as the
leading outflow approaches from Lake Superior. Sufficient
instability/shear will also support some threat of marginally severe
hail with the strongest cores. 

The wind/hail threat should diminish with time further east, as the
thunderstorm cluster encounters cooler boundary-layer temperatures
and stronger CINH. Given the relatively confined spatiotemporal
nature of the threat, watch issuance is not anticipated.

..Dean/Edwards.. 09/01/2018

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

ATTN...WFO...MQT...

LAT...LON   47248981 47518815 47378701 46248747 46148826 46288916
            46489000 46689019 47188994 47248981 

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