SPC MD 1439

MD 1439 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF FAR NORTH-NORTHEAST WISCONSIN INTO THE WESTERN UPPER PENINSULA OF MICHIGAN

Mesoscale Discussion 1439
NWS Storm Prediction Center Norman OK
0701 PM CDT Sun Aug 09 2020

Areas affected...Portions of far north-northeast Wisconsin into the
western Upper Peninsula of Michigan

Concerning...Severe potential...Watch unlikely 

Valid 100001Z - 100200Z

Probability of Watch Issuance...20 percent

SUMMARY...A couple damaging gusts and perhaps a brief tornado may
accompany the stronger storms. The isolated, brief nature of the
severe threat suggests that a WW issuance may not be needed.

DISCUSSION...Semi-discrete cells and cellular cluster have recently
experienced a modest uptick in intensity across far northern
Wisconsin in closer proximity to the center of an MCV based on
trends via the latest mosaic MRMS composite radar data. These storms
are approaching an ambient environment characterized by 7+ C/km
low-level lapse rates (per latest Mesoanalysis) and near 70F surface
dewpoints (based on METAR observations), contributing to 2000 J/kg
MLCAPE, with up to 200 J/kg concentrated in the lowest 3km. In
addition, modest veering and strengthening of the winds with height
in the lowest 3km are contributing to 30-35 knots of effective bulk
shear and 100 m2/s2 effective SRH, with decently curved hodographs
noted in the latest RAP forecast soundings. 

As such, some severe threat may accompany any of the stronger,
longer lasting storms, particularly with storms that can remain
discrete. The primary threat would be damaging gusts given the
steeper low-level lapse rates. However, any storm that can become
highly organized may be able to take advantage of the stronger
low-level CAPE/shear to support the development of a brief tornado
or two. Nonetheless, the severe threat is expected to remain
localized, and a WW issuance is not currently anticipated.

..Squitieri/Dial.. 08/10/2020

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

ATTN...WFO...MQT...GRB...DLH...

LAT...LON   45969094 46349084 46669047 46888985 47078875 46978788
            46728741 46458742 46108775 45838818 45728895 45739015
            45969094 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1439.html