Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 181926
SPC MCD 181926

Mesoscale Discussion 0297
NWS Storm Prediction Center Norman OK
0226 PM CDT Sat Mar 18 2017

Areas affected...Central VA...Central NC...North-central SC...Far
eastern WV

Concerning...Severe potential...Watch unlikely

Valid 181926Z - 182200Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered thunderstorms will be capable of at least small
hail and locally damaging wind this afternoon. The magnitude of the
threat appears too low for watch issuance.

DISCUSSION...At 1915Z, scattered thunderstorms are ongoing across
portions of WV, with more isolated activity extending further south
down the Appalachians. These storms are associated with a strong
shortwave trough and associated cold front moving eastward through
the Ohio Valley. Minimal instability has limited the intensity of
these storms thus far, though steep midlevel lapse rates and cold
temperatures aloft have supported some small hail. Ahead of this
activity, clearing skies have allowed some heating to occur across
central VA/NC, and as storms advance/develop eastward with time,
some uptick in intensity is possible as available instability slowly

While convection may remain rather shallow across central VA and
north-central NC, effective shear will still be sufficient for some
storm organization. Cold temperatures aloft will continue to support
at least small hail, with a marginal severe hail risk present with
the strongest updrafts. Steep low-level lapse rates will support
locally gusty winds as well.

Further south across southern NC and northern SC, somewhat deeper
convection may evolve with time, given greater boundary-layer
theta-E compared to areas further north. Cumulus is increasing along
a weak east-west oriented surface boundary in this area. A marginal
severe hail risk will exist with the strongest updrafts in this
area, given sufficient effective shear. Also, somewhat greater cloud
water content may support a higher damaging wind risk, especially if
convection can evolve into one or more line segments with time.

Much of the short-term guidance indicates a relative minimum in
storm coverage across central NC, between the two areas described
above, though the environment would conditionally support a marginal
wind/hail risk in this area as well. Throughout the MCD area, the
overall threat is expected to remain too low for watch issuance.

..Dean/Hart.. 03/18/2017

...Please see for graphic product...


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