Alert archive / Pennsylvania / Mesoscale Discussions in 2013

Mesoscale Discussion 846

May 28, 2013Trumbull County, Ohio; 14 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at May 28, 2013, 8:42 PM EDT for Trumbull County, Ohio; 14 counties in Pennsylvania. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: May 28, 2013, 8:42 PM EDT (00:42 UTC)
Expired: May 28, 2013, 10:15 PM EDT
In force: 93 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Trumbull County, OH, Cameron County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Crawford County, PA, Elk County, PA, Forest County, PA, Jefferson County, PA, McKean County, PA, Mercer County, PA, Potter County, PA, Venango County, PA, Warren County, PA

The radar

The State College radar (KCCX), 113 km from the middle of the area, began a volume at 00:45 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, 0.7 hours before the alert went out and 149 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: 182 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 1298 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 170 m²/s²
0-3 km storm-relative helicity: 220 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.0

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
May 28, 9:20 PM EDT	Mesoscale Discussion	SPC	Defiance, Erie, Fulton, Henry, Lucas, Ottawa and 6 more	115 min
May 28, 11:46 PM EDT	Mesoscale Discussion	SPC	Defiance, Fulton, Henry, Paulding, Williams	89 min
May 29, 11:38 AM EDT	Mesoscale Discussion	SPC	Bradford, Cameron, Centre, Clarion, Clearfield, Clinton and 19 more	2 hr
May 29, 3:19 PM EDT	Severe Thunderstorm Watch	SPC	Bradford, Lackawanna, Luzerne, Lycoming, McKean, Pike and 6 more	8 hr
May 29, 5:56 PM EDT	Mesoscale Discussion	SPC	Bradford, Lackawanna, Lycoming, Pike, Sullivan, Susquehanna and 3 more	64 min

Nearby

Mesoscale Discussions in Pennsylvania, 2013 Mesoscale Discussions in Ohio, 2013 Every mesoscale discussion in 2013

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.