Mesoscale Discussion 1099
NWS Storm Prediction Center Norman OK
1259 PM CDT Tue Jun 20 2017
Areas affected...Parts of northwestern/central Kansas and adjacent
Concerning...Severe potential...Watch possible
Valid 201759Z - 202000Z
Probability of Watch Issuance...60 percent
SUMMARY...Isolated to scattered rapid severe storm development
appears possible as early as 19-21Z, with large hail the primary
initial severe threat. Strong surface gusts may become an
increasing concern near storms later this afternoon. Trends are
being monitored for the possibility of a severe weather watch.
DISCUSSION...Surface heating along/west of a corridor of boundary
layer moisture return across the Liberal/Dodge City areas,
northeastward through Russell/Hill City, has already contributed to
strong potential instability. This is occurring beneath steepening
mid-level lapse rates associated with the leading edge of elevated
mixed layer air beginning to return eastward across the high Plains.
In the presence of generally weak but veering winds with height,
beneath 30-40 kt northwesterly flow around 500 mb, the environment
appears conditionally supportive of organized severe storm
development, including supercells.
Although the Rapid Refresh suggests that mid-level inhibition is
weakening with continuing insolation, this probably is being offset,
at least somewhat, by gradual warming aloft. Still, large-scale
ascent associated with lower/mid tropospheric warm advection could
support the initiation of thunderstorms. And there appears a
general consensus among various model output that this may occur as
early as 19-21Z, roughly centered around the Russell/Hill City area.
Once initiation of deep convection commences, fairly rapid
intensification appears possible, accompanied by a risk for severe
hail, some of which could be very large.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 40170051 40119928 39879787 39049775 38159854 38039998