Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 181632
SWOMCD
SPC MCD 181631
NYZ000-PAZ000-WVZ000-OHZ000-181830-

Mesoscale Discussion 1084
NWS Storm Prediction Center Norman OK
1131 AM CDT Sun Jun 18 2017

Areas affected...portions of western and central New York...northern
and western Pennsylvania...central and eastern Ohio...and the
northern West Virginia Panhandle

Concerning...Severe potential...Watch possible

Valid 181631Z - 181830Z

Probability of Watch Issuance...60 percent

SUMMARY...A gradually increasing cu field will likely lead to
scattered thunderstorm development over the next 1-2 hours.  With an
associated risk for locally damaging winds and marginal hail likely
to accompany stronger storms, WW issuance may be required.

DISCUSSION...Latest visible satellite loop shows an increasing
cumulus coverage/depth from southwest Ohio northeast to northwest
Pennsylvania and western New York, in the vicinity of Lake Erie.
This appears to be loosely tied to a pre-frontal confluence axis
lying across central Ohio, and hints of a lake-breeze boundary over
western New York.

Diurnal heating through broken cloud cover in conjunction with
boundary-layer dewpoints mainly in the upper 60s is supporting
mixed-layer cape now in excess of 1000 J/kg across the area, with
additional heating/destabilization expected to fuel eventual
development of scattered thunderstorms -- aided increasing
large-scale ascent spreading across the region ahead of the upper
Great Lakes short-wave trough.

Morning RAOBs and the latest VWP data from the region indicate
moderate/roughly unidirectional southwesterly flow with height,
which will support some updraft organization and likely eventual
upscale growth into lines/bands of storms.  With resulting potential
for locally damaging winds arising from the organizing convection,
along with some risk for hail, indications are that a WW will likely
be required across this area within the next 1-2 hours.

..Goss/Weiss.. 06/18/2017

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

ATTN...WFO...BGM...BUF...CTP...PBZ...RLX...CLE...ILN...

LAT...LON   43737541 42557565 40047931 39268190 40288303 41518298
            41988217 42837950 43527883 43937642 43737541




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