ZCZC SPCSWOMCD ALL
ACUS11 KWNS 180204 
SPC MCD 180204 
VAZ000-NCZ000-SCZ000-WVZ000-TNZ000-180400-

Mesoscale Discussion 1549
NWS Storm Prediction Center Norman OK
0904 PM CDT Tue Aug 17 2021

Areas affected...western north Carolina and southern virginia

Concerning...Tornado Watch 446...

Valid 180204Z - 180400Z

The severe weather threat for Tornado Watch 446 continues.

SUMMARY...A few tornadoes remain possible across WW462 this evening.
As instability decreases the tornado threat should dampen some
overnight.

DISCUSSION...As of 0150 UTC, regional radar imagery showed a loosely
organized rain band associated with tropical cyclone Fred extending
south through the western Carolinas. Within the band, a mostly
linear convective mode has limited the tornado potential somewhat
over the last couple of hours. The local environment still remain
favorable for updraft rotation and tornadoes with the FCX and TCLT
VADs showing large low-level hodographs and 0-1km SRH greater than
250 m2/s2. While thermodynamically, the loss of diurnal heating has
resulted in decreasing buoyancy, this will be offset somewhat by an
increasingly moist airmass (75+ F dewpoints) associated with the
warm core of Fred. MLCAPE values are generally expected to remain
below 1000 J/kg across upstate North Carolina and southwestern
Virginia, but this should remain adequate to support a few rotating
storms through this evening into southern Virginia.

..Lyons.. 08/18/2021

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

ATTN...WFO...RAH...RNK...CAE...GSP...MRX...

LAT...LON   34868029 34708094 34738137 34998163 35378163 35838168
            36288186 36578186 36918171 37128138 37228115 37488066
            37697995 37627960 37367928 36937924 36787923 36167946
            35477977 34868029 

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