Alert archive / Pennsylvania / Mesoscale Discussions in 2013

Mesoscale Discussion 773

May 22, 2013Frederick County, Washington County, Maryland; 14 counties in Pennsylvania; Jefferson County, West Virginia

The Storm Prediction Center issued this mesoscale discussion at May 22, 2013, 6:20 PM EDT for Frederick County, Washington County, Maryland; 14 counties in Pennsylvania; Jefferson County, West Virginia. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: May 22, 2013, 6:20 PM EDT (22:20 UTC)
Expired: May 22, 2013, 7:45 PM EDT
In force: 85 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Frederick County, MD, Washington County, MD, Adams County, PA, Centre County, PA, Clinton County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Juniata County, PA, Lycoming County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Snyder County, PA, Union County, PA, Jefferson County, WV

The radar

The State College radar (KCCX), 85 km from the middle of the area, began a volume at 22:21 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.3 hours before the alert went out and 144 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: 745 J/kg
Mixed-layer CIN: -155 J/kg
Mixed-layer LCL: 742 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 40 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
May 22, 2:27 PM EDT	Severe Thunderstorm Watch	SPC	Garrett	7 hr
May 22, 3:53 PM EDT	Mesoscale Discussion	SPC	Allegany, Carroll, Frederick, Washington	67 min
May 22, 11:31 AM EDT	Mesoscale Discussion	SPC	Lackawanna, Monroe, Pike, Susquehanna, Wayne, Wyoming	119 min
May 22, 12:58 PM EDT	Severe Thunderstorm Watch	SPC	Lackawanna, Luzerne, Pike, Susquehanna, Wayne, Wyoming	10 hr
May 22, 2:08 PM EDT	Mesoscale Discussion	SPC	Allegheny, Armstrong, Beaver, Butler, Clarion, Crawford and 8 more	2 hr
May 22, 3:41 PM EDT	Severe Thunderstorm Watch	SPC	Bradford, Susquehanna, Wayne	7 hr
May 22, 4:28 PM EDT	Mesoscale Discussion	SPC	Lackawanna, Sullivan, Susquehanna, Wayne, Wyoming	92 min
May 22, 7:41 PM EDT	Mesoscale Discussion	SPC	Bradford, Lackawanna, Luzerne, Pike, Sullivan, Susquehanna and 3 more	94 min

Nearby

Mesoscale Discussions in Pennsylvania, 2013 Mesoscale Discussions in Maryland, 2013 Mesoscale Discussions in West Virginia, 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.