ZCZC SPCSWOMCD ALL
ACUS11 KWNS 271236 
SPC MCD 271236 
LAZ000-TXZ000-271400-

Mesoscale Discussion 1911
NWS Storm Prediction Center Norman OK
0736 AM CDT Wed Oct 27 2021

Areas affected...Parts of the upper Texas and Louisiana coast
vicinity

Concerning...Severe potential...Watch likely 

Valid 271236Z - 271400Z

Probability of Watch Issuance...80 percent

SUMMARY...Discrete thunderstorm development is ongoing and likely to
continue across the region into mid morning.  It appears that this
will include the evolution of a few supercell structures which may
begin to pose a risk for tornadoes.

DISCUSSION...Thunderstorm activity on the leading edge of the
southeastward advancing, convectively generated surface cold pool
has yet to show signs of appreciable intensification, and the window
of opportunity for this to occur appears to be narrowing, with it on
track to reach mid/upper Texas coastal areas by or shortly after
15Z.  However, this activity is now preceded by scattered discrete
thunderstorm development, likely rooted within the seasonably moist
and moderately unstable boundary layer, near upper Texas and
southwestern Louisiana coastal areas.  These storms probably have
been supported by forcing associated with weak low-level warm
advection, with at least one cell with a sustained low-level
mesocyclone offshore east of Galveston.  

The isolated supercell may advance inland across coastal areas
southwest of Beaumont/Port Arthur during the next hour or two, and
similar additional development near coastal areas appears at least
possible through 14-15Z.  Although cloud cover may slow
boundary-layer destabilization inland across southwestern into south
central Louisiana coastal areas, strengthening of southerly 850 mb
flow (in excess of 30 kt) is ongoing, and will contribute to
enlarging clockwise curved low-level hodographs.

..Kerr/Guyer.. 10/27/2021

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

ATTN...WFO...LIX...LCH...HGX...

LAT...LON   30799463 30949382 30489287 30149168 29779078 29089063
            28969144 29269316 29269464 29839501 30189475 30799463 

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