SPC MD 1700

MD 1700 CONCERNING TORNADO WATCH 492... FOR THE CAROLINA COASTAL PLAIN

Mesoscale Discussion 1700
NWS Storm Prediction Center Norman OK
0927 AM CDT Thu Sep 17 2020

Areas affected...The Carolina coastal plain

Concerning...Tornado Watch 492...

Valid 171427Z - 171630Z

The severe weather threat for Tornado Watch 492 continues.

SUMMARY...Potential for tornadoes is expected to increase through
early to mid afternoon, with a strong tornado or two possible.

DISCUSSION...As the shearing remnants of Sally gradually migrate
east-northeastward toward the Carolinas, vigorous convective
development is already underway across the South Carolina coastal
plain, with  an isolated sustained supercell ongoing near/east of
Orangeburg SC.  This is occurring along a surface warm frontal zone
which extends east-northeastward across the South Carolina coastal
plain, north of the Myrtle Beach area, into immediate North Carolina
coastal areas.  At least some further inland advancement of this
front seems probable through early afternoon, particularly across
the North Carolina coastal plain.

Near the nose of a 30-40 kt southerly 850 mb jet, now curving across
southeast Georgia into the South Carolina Piedmont, and slowly
shifting eastward, near surface vertical shear will become maximized
along this front as the moist boundary layer destabilizes with at
least weak to modest boundary layer warming through early afternoon.
This environment seems likely to become increasingly conducive to
tornadic development through 18-20Z, and could include the risk for
a strong tornado.

..Kerr.. 09/17/2020

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

ATTN...WFO...RAH...ILM...CHS...CAE...

LAT...LON   34098075 35087945 35297860 34617859 34187871 33057998
            32708062 33628088 34098075 

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