Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 180310
SWOMCD
SPC MCD 180309
NCZ000-VAZ000-180715-

Mesoscale Discussion 0031
NWS Storm Prediction Center Norman OK
0909 PM CST Wed Jan 17 2018

Areas affected...The Outer Banks area of North Carolina into the
Tidewater area of southeast Virginia

Concerning...Heavy snow

Valid 180309Z - 180715Z

SUMMARY...Heavy snow rates in excess of 1 inch per hour, including
occasional heavier convective bursts, may develop across the North
Carolina Outer Banks area, possibly into portions of the Virginia
Tidewater, during the 11 PM to 4 AM time frame.

DISCUSSION...A significant mid-level trough is forecast to continue
pivoting east of the southern Appalachians during the next few
hours.  As it does, models suggest that it may take on more of a
neutral to negative tilt, accompanied by an increasingly better
defined lower/mid tropospheric cyclonic circulation center across
the piedmont through coastal areas.  This appears likely to
contribute to a consolidating area of upward vertical motion, with
considerable strengthening by the 05-08Z time frame, centered across
the Outer Banks area of North Carolina.

Aided by dynamic cooling, cold advection and melting precipitation,
thermodynamic profiles near immediate coastal areas are expected to
cool entirely below freezing, supporting snow or a changeover to
snow.  Rapid Refresh forecast soundings indicate that lift may
become maximized within the dendritic growth layer for several
hours, supporting snow rates in excess of 1 inch per hour, in the
presence of precipitable water between .5 and .75 inches.  At least
some convective enhancement appears possible leading to occasional
heavier bursts of snow, before diminishing/spreading offshore after
08-09Z.

It is possible similar snow rates could impact portions of the
southeast Virginia Tidewater, but the most prolonged/heaviest snow
appears most likely to the south, across the Outer Banks area
near/north of Cape Hatteras.

..Kerr.. 01/18/2018

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

ATTN...WFO...AKQ...MHX...

LAT...LON   36377656 36697547 34977525 35127595 35307683 36377656




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