000
ACUS11 KWNS 240026
SWOMCD
SPC MCD 240025
NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-WVZ000-240130-

Mesoscale Discussion 1142
NWS Storm Prediction Center Norman OK
0725 PM CDT Fri Jun 23 2017

Areas affected...West Virginia...Maryland...Pennsylvania...New
Jersey...Delaware

Concerning...Severe Thunderstorm Watch 366...369...

Valid 240025Z - 240130Z

The severe weather threat for Severe Thunderstorm Watch 366, 369
continues.

SUMMARY...A severe threat is ongoing across parts of the
Mid-Atlantic early this evening. Damaging wind gusts or a brief
tornado will be possible but the severe threat is expected to
gradually diminish over the next couple of hours. Additional Weather
Watch issuance is not expected.

DISCUSSION...Radar imagery shows the remnants of Cindy across
central Kentucky with a band of convection extending to the
east-northeast across northern West Virginia, southern Pennsylvania
into northern New Jersey. Surface dewpoints along this corridor are
in the upper 60s and lower 70s F with the RAP showing moderate
instability mainly in the eastern part of the MCD area. This is
confirmed by the 00Z sounding at Washington DC which shows SBCAPE
near 1500 J/kg. This sounding also shows 0-6 km shear near 50 kt
along with 0-3 km storm relative helicity of 250 m2/s2. Low-level
shear is likely stronger westward into the northern part of West
Virginia. This is where a brief tornado will be possible over the
next hour or so with small discrete cells that rotate. A few strong
wind gusts will also be possible especially southeastern
Pennsylvania where a short line segment is ongoing. The severe
threat appears to be minimal and the watches will be allowed to
expire at 02Z. The situation will continue to be monitored in the
case that an isolated severe threat ramps up later this evening.

..Broyles/Hart.. 06/24/2017

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

ATTN...WFO...OKX...PHI...CTP...LWX...PBZ...RLX...

LAT...LON   39237438 39007648 38887973 38988038 39448032 39667953
            40777529 40597376 39237438