|Mesoscale Discussion 1248|
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Mesoscale Discussion 1248
NWS Storm Prediction Center Norman OK
0504 PM CDT Thu Jul 06 2017
Areas affected...portions of northern and central WI...western Upper
Peninsula of MI
Concerning...Severe potential...Watch possible
Valid 062204Z - 070000Z
Probability of Watch Issuance...40 percent
SUMMARY...Thunderstorms will likely intensify this afternoon while
moving southeast across the western Lake Superior vicinity and into
adjacent portions of WI and MI. Uncertainty remains how
thunderstorms will evolve and the overall strength/coverage of
strong to severe storm activity.
DISCUSSION...Visible satellite imagery shows a cumulus field
beginning to develop across north-central WI east-southeast to the
south of the Door Peninsula. Thunderstorms from early-day
convection have moved east towards Lake Huron but outflow from this
activity spread across northern WI into the western Upper Peninsula.
The region within the influence of the outflow is most evident in
both the lack of vigorous cumulus growth and drier low levels with
surface dewpoints in the upper 50s to lower 60s degrees F.
Veered boundary-layer flow (reference deep westerly flow from KDLH
and KGRB) has contributed to a lack of strong low-level convergence.
Nonetheless, strengthening winds with height (40-60 kt in the 4-8 km
layer per KDLH VAD data) will act to organize updrafts. It appears
the strongest storms will move southeast along the outflow/buoyancy
gradient located from near ASX to GRB. Isolated large hail and
isolated to scattered gusts (50-65 mph) capable of wind damage, are
possible this evening. Convective trends will be monitored for the
possibility of a severe thunderstorm watch.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 45579143 46099137 46569063 46838937 45548722 44998710
43828766 43768897 45579143
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