Alert archive / Pennsylvania / Mesoscale Discussions in 2011

Mesoscale Discussion 586

April 26, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Apr 26, 2011, 1:18 PM EDT for 4 states. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued: Apr 26, 2011, 1:18 PM EDT (17:18 UTC)
Expired: Apr 26, 2011, 2:15 PM EDT
In force: 57 min
Issued by: the Storm Prediction Center

All 78 counties

Allegany County, MD, Garrett County, MD, Washington County, MD, Allegany County, NY, Broome County, NY, Cattaraugus County, NY, Cayuga County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Livingston County, NY, Madison County, NY, Oneida County, NY, Onondaga County, NY, Ontario County, NY, Otsego County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Wyoming County, NY, Yates County, NY, Allegheny County, PA, Armstrong County, PA, Bedford County, PA, Blair County, PA, Bradford County, PA, Butler County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Elk County, PA, Fayette County, PA, Forest County, PA, Franklin County, PA, Fulton County, PA, Greene County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Lycoming County, PA, McKean County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Washington County, PA, Westmoreland County, PA, Wyoming County, PA, Barbour County, WV, Berkeley County, WV, Doddridge County, WV, Grant County, WV, Hampshire County, WV, Harrison County, WV, Marion County, WV, Mineral County, WV, Monongalia County, WV, Morgan County, WV, Preston County, WV, Taylor County, WV, Tucker County, WV, Wetzel County, WV

The radar

The State College radar (KCCX), 69 km from the middle of the area, began a volume at 17:19 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 5.3 hours before the alert went out and 219 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 493 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 237 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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
Apr 26, 1:49 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett	56 min
Apr 26, 1:49 PM EDT	Severe Thunderstorm Watch	SPC	Garrett	7 hr
Apr 26, 2:09 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Washington	7 hr
Apr 26, 4:34 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett, Washington	56 min
Apr 26, 7:44 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett, Washington	61 min
Apr 26, 4:12 PM EDT	Mesoscale Discussion	SPC	Albany, Broome, Chemung, Chenango, Cortland, Delaware and 22 more	63 min
Apr 26, 6:51 PM EDT	Mesoscale Discussion	SPC	Allegany, Broome, Cayuga, Chemung, Chenango, Cortland and 21 more	54 min

Nearby

Mesoscale Discussions in Pennsylvania, 2011 Mesoscale Discussions in New York, 2011 Mesoscale Discussions in West Virginia, 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.