ZCZC SPCSWOMCD ALL
ACUS11 KWNS 221853 
SPC MCD 221853 
PAZ000-222100-

Mesoscale Discussion 1833
NWS Storm Prediction Center Norman OK
0153 PM CDT Thu Aug 22 2019

Areas affected...Pennsylvania

Concerning...Severe potential...Watch unlikely 

Valid 221853Z - 222100Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorm activity is expected to continue to develop
and increase across the region through 4-6 PM, accompanied by at
least some risk for potentially damaging wind gusts.  This threat
still appears isolated/marginal enough that a watch will not be
needed, but trends will continue to be monitored.

DISCUSSION...Deepening convection along the primary surface front,
near the Interstate 70 corridor through the western slopes of the
Allegheny mountains, may be aided by forcing for ascent associated
with a remnant convectively generated or enhanced mid-level
perturbation.  This impulse is accompanied by a seasonably strong
westerly mid-level speed maximum, including 30-50 kt in the 2-5 km
(AGL) layer, and forecast to progress east of the Alleghenies,
across much of central Pennsylvania through 20-22Z.

Due to generally weak mid/upper lapse rates, CAPE for moist boundary
layer air characterized by mid/upper 60s F surface dew points is
generally weak across much of the region.  However, it may still be
sufficient to support increasing convection and embedded
thunderstorm activity.  Coinciding with peak daytime heating, and
apparent relatively deep boundary layer mixing, the environment may
still become conducive to locally strong downbursts near the most
vigorous convection, which may be accompanied by potentially
damaging surface gusts.

..Kerr/Guyer.. 08/22/2019

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

ATTN...WFO...PHI...BGM...CTP...PBZ...

LAT...LON   41097889 41517644 40917557 40357630 40207691 40247838
            40257945 41097889 

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