Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 192044
SWOMCD
SPC MCD 192043
PAZ000-MDZ000-WVZ000-OHZ000-192245-

Mesoscale Discussion 1531
NWS Storm Prediction Center Norman OK
0343 PM CDT Sat Aug 19 2017

Areas affected...Eastern Ohio...Southwest and Central Pennsylvania

Concerning...Severe Thunderstorm Watch 457...

Valid 192043Z - 192245Z

The severe weather threat for Severe Thunderstorm Watch 457
continues.

SUMMARY...A wind damage and hail threat will likely continue for
several more hours as cells move across southwestern and central
Pennsylvania. The storms will likely approach the eastern edge of
the watch by early evening but the issuance of another watch appears
unlikely.

DISCUSSION...The latest radar data shows a mult-segmented line from
about 80 statute miles northeast of Pittsburgh extending
west-southwestward into eastern Ohio. The line of storms is located
along a cold front with mid 60s F surface dewpoints located ahead of
the front. This is resulting in a narrow corridor of instability
with the RAP showing MLCAPE values in the 1000 to 1200 J/kg range.
In addition, the Pittsburgh and College Station PA WSR-88D VWPs show
30 to 40 kts of westerly flow in the mid-levels. This is accompanied
by a slight backing of the winds with height. In spite of the
backing, the amount of flow combined with steep low-level lapse
rates of near 7.5 C/km according to the RAP should be favorable for
isolated damaging wind gusts with the stronger cells along the line.
Hail could also occur in the more intense cores.

..Broyles/Weiss.. 08/19/2017

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

ATTN...WFO...CTP...LWX...PBZ...RLX...CLE...ILN...

LAT...LON   39697746 39738083 39588090 39528108 39638142 39568146
            39568156 39768162 39758205 39828214 39938221 40428216
            40458162 40638166 40688107 40908107 40878050 41128053
            41048003 41167994 41157958 41357948 41647951 41627814
            41497798 41457757 41517753 41537690 41567685 41337665
            41297648 41197662 41197684 41087687 40927685 40807693
            40517700 40307681 40177694 39967742 39697746




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