000
ACUS11 KWNS 231554
SWOMCD
SPC MCD 231554
TNZ000-ALZ000-MSZ000-231730-

Mesoscale Discussion 1130
NWS Storm Prediction Center Norman OK
1054 AM CDT Fri Jun 23 2017

Areas affected...Middle TN...Northeast MS...Central/northern AL

Concerning...Severe potential...Watch likely

Valid 231554Z - 231730Z

Probability of Watch Issuance...80 percent

SUMMARY...A gradual increase in the severe threat is expected late
this morning into the afternoon. A few tornadoes and isolated
damaging wind gusts will be the primary threats. Watch issuance is
likely late this morning or early this afternoon.

DISCUSSION...Convection has been increasing in intensity this
morning, along the leading edge of the broader precipitation shield
associated with TC Cindy. The environment ahead this convection is
characterized by very moist/tropical profiles, with poor lapse rates
but favorable wind profiles for supercells and other organized storm
structures. As continued heating and modest destabilization occurs
downstream, the severe threat is expected to increase. Recent CAM
guidance is suggestive of a mixed-mode threat, with some tornado
threat resulting from mini-supercell development, while a threat of
damaging wind gusts will increase with larger-scale convective line
segments.

In a relative sense, the tornado threat will likely be greatest
across the northern portion of the MCD area, where backed low-level
flow will increase low-level shear/SRH, while the wind threat may be
maximized further south, where low-level flow remains strong but
vertical profiles would tend to favor line segments. One or more
watches are likely late this morning or early this afternoon to
cover these threats.

..Dean/Guyer.. 06/23/2017

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

ATTN...WFO...MRX...OHX...BMX...HUN...MEG...JAN...

LAT...LON   32738981 34308877 34918835 35978756 36608692 36558519
            35538531 34518597 32908682 32638729 32518820 32488932
            32738981