Alert archive / Pennsylvania / Mesoscale Discussions in 2011

Mesoscale Discussion 1699

July 22, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Jul 22, 2011, 8:13 PM EDT for 4 states. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued: Jul 22, 2011, 8:13 PM EDT (00:13 UTC)
Expired: Jul 22, 2011, 9:15 PM EDT
In force: 62 min
Issued by: the Storm Prediction Center

All 36 counties

Garrett County, MD, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Harrison County, OH, Jefferson County, OH, Mahoning County, OH, Monroe County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Bedford County, PA, Blair County, PA, Butler County, PA, Cambria County, PA, Clarion County, PA, Clearfield County, PA, Elk County, PA, Fayette County, PA, Greene County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, Mercer County, PA, Somerset County, PA, Venango County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Hancock County, WV, Marion County, WV, Marshall County, WV, Monongalia County, WV, Ohio County, WV, Preston County, WV, Wetzel County, WV

The radar

The Pittsburgh radar (KPBZ), 59 km from the middle of the area, began a volume at 00:13 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 00:00Z, 0.2 hours before the alert went out and 48 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 111 J/kg
Mixed-layer CIN: -262 J/kg
Mixed-layer LCL: 1450 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -46 m²/s²
0-3 km storm-relative helicity: -7 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 23, 3:18 PM EDT	Mesoscale Discussion	SPC	Allen, Ashland, Auglaize, Champaign, Coshocton, Crawford and 24 more	87 min
Jul 23, 7:06 PM EDT	Mesoscale Discussion	SPC	Cuyahoga, Defiance, Erie, Fulton, Geauga, Hancock and 12 more	114 min

Nearby

Mesoscale Discussions in Pennsylvania, 2011 Mesoscale Discussions in West Virginia, 2011 Mesoscale Discussions in Ohio, 2011 Every mesoscale discussion in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.