Alert archive / Pennsylvania / Mesoscale Discussions in 2015

Mesoscale Discussion 851

May 31, 20155 states

The Storm Prediction Center issued this mesoscale discussion at May 31, 2015, 12:51 PM EDT for 5 states. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: May 31, 2015, 12:51 PM EDT (16:51 UTC)
Expired: May 31, 2015, 2:45 PM EDT
In force: 114 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 55 counties

Allegany County, MD, Frederick County, MD, Washington County, MD, Columbiana County, OH, Jefferson County, OH, Adams County, PA, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Bedford County, PA, Blair County, PA, Butler County, PA, Cambria County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Cumberland County, PA, Dauphin County, PA, Elk County, PA, Fayette County, PA, Franklin County, PA, Fulton County, PA, Greene County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Lawrence County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Snyder County, PA, Somerset County, PA, Union County, PA, Washington County, PA, Westmoreland County, PA, City of Winchester, VA, Clarke County, VA, Frederick County, VA, Shenandoah County, VA, Warren County, VA, Berkeley County, WV, Brooke County, WV, Hampshire County, WV, Hancock County, WV, Hardy County, WV, Jefferson County, WV, Marshall County, WV, Mineral County, WV, Monongalia County, WV, Morgan County, WV, Ohio County, WV, Wetzel County, WV

The radar

The Pittsburgh radar (KPBZ), 104 km from the middle of the area, began a volume at 16:51 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 (KAGC), launched 12:00Z, 4.9 hours before the alert went out and 89 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: 78 J/kg
Mixed-layer CIN: -66 J/kg
Mixed-layer LCL: 964 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 146 m²/s²
0-3 km storm-relative helicity: 172 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

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Nearby

Mesoscale Discussions in Pennsylvania, 2015 Mesoscale Discussions in West Virginia, 2015 Mesoscale Discussions in Virginia, 2015 Every mesoscale discussion in 2015

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.