Severe Storm Outlook Narrative (AC)
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ACUS01 KWNS 231943
SWODY1
SPC AC 231942

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0242 PM CDT Wed Aug 23 2017

Valid 232000Z - 241200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
CAROLINAS INTO SOUTHEASTERN VIRGINIA...

...SUMMARY...
A few strong to severe storms may impact parts of the southern
Mid-Atlantic region and eastern Carolinas this afternoon and
evening. Gusty, damaging winds will be the main threat.

...20Z Outlook Update...
Minimal changes are needed to the ongoing outlook.  Scattered storms
have developed as anticipated in portions of Virginia and North
Carolina.  Isolated damaging wind gusts remain possible with the
most organized activity given moderate to strong instability within
the pre-convective airmass and 25-30 knot deep shear.

Elsewhere, scattered and mostly sub-severe storms have developed
across portions of the South westward to the Intermountain West.  A
diurnally driven uptick in this activity is expected to continue
into the early evening hours.

..Cook.. 08/23/2017

.PREV DISCUSSION... /ISSUED 1114 AM CDT Wed Aug 23 2017/

...Carolinas to Southeast Virginia...

Weak large-scale height falls will spread across the central
Appalachians into the Middle Atlantic region this afternoon along
southern fringes of OH Valley upper trough. Pre-frontal air mass is
warming rapidly through the mid 80s across the Carolinas into
southeast VA and low-level lapse rates should steepen sufficiently
for parcels to breach their convective temperatures by 18z. Latest
vis satellite imagery displays a substantial cumulus field over
southeast VA, with deeper updrafts along the advancing front, and
scattered thunderstorms should evolve along the front over southern
VA then spread/develop into eastern NC as the afternoon progresses.
Early-morning sounding data exhibits very high PW environment with
poor mid-level lapse rates. While modest westerly flow aloft will
skirt the VA/NC border region, enhancing the prospect for some
organization, thermodynamic profiles along with forecast shear
suggest 5% severe probs adequately reflect the overall severe wind
potential with afternoon/evening convection.

$$



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