Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 150742
SWOMCD
SPC MCD 150741
WIZ000-MIZ000-MNZ000-151015-

Mesoscale Discussion 0742
NWS Storm Prediction Center Norman OK
0241 AM CDT Fri Jun 15 2018

Areas affected...Northeast Minnesota/western Lake Superior vicinity
into central Wisconsin

Concerning...Severe potential...Watch unlikely

Valid 150741Z - 151015Z

Probability of Watch Issuance...20 percent

SUMMARY...Increasing thunderstorm development is expected through
the 4-6 AM CDT time frame, with the risk for large hail the primary
potential severe hazard.  Due to the generally isolated nature of
the expected threat, a severe weather watch is not anticipated, but
trends will be monitored.

DISCUSSION...The 40-50 kt low-level jet continues to gradually veer
to an increasingly southwesterly component while shifting east of
the Dakotas into the upper Mississippi Valley.  Downstream of a
short wave trough now progressing northeastward into southern
Saskatchewan, a zone of enhanced low-level warm advection is
forecast to develop across the Minnesota Arrowhead and western Lake
Superior vicinity into north central Wisconsin.  This is generally
just east of the nose of the warm and more strongly capping elevated
mixed layer plume emanating from the Great Basin.  Models suggest
that this will coincide with elevated moisture return (within the
850-700 mb layer) underrunning the cap, which may contribute to
rapid destabilization and increasing thunderstorm development
through the 09-11Z time frame.  This will generally be based above a
relatively cool/stable surface based air mass associated with a
surface high centered over the Great Lakes.  However, the
development of moderately large CAPE, in the presence of at least
modest vertical shear within the convective layer, probably will be
sufficient to support at least some risk for severe hail.

..Kerr/Hart.. 06/15/2018

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

ATTN...WFO...MQT...GRB...DLH...ARX...MPX...

LAT...LON   47858966 46648933 44978917 44049043 45059090 45839132
            46929199 48069275 49019083 47858966




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