Alert archive / Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 1195

June 12, 20117 counties in Maryland; 10 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jun 12, 2011, 3:39 PM EDT for 7 counties in Maryland; 10 counties in Virginia. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Jun 12, 2011, 3:39 PM EDT (19:39 UTC)
Expired: Jun 12, 2011, 5:15 PM EDT
In force: 96 min
Issued by: the Storm Prediction Center

Counties Anne Arundel County, MD, Baltimore County, MD, Charles County, MD, City of Baltimore, MD, Howard County, MD, Montgomery County, MD, Prince George's County, MD, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Manassas, VA, City of Manassas Park, VA, Fairfax County, VA, Fauquier County, VA, Prince William County, VA, Stafford County, VA

The radar

The Sterling radar (KLWX), 36 km from the middle of the area, began a volume at 19:39 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.7 hours before the alert went out and 28 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: 360 J/kg
Mixed-layer CIN: -50 J/kg
Mixed-layer LCL: 861 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -27 m²/s²
0-3 km storm-relative helicity: 2 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
Jun 12, 12:03 PM EDT	Mesoscale Discussion	SPC	Allegany, Anne Arundel, Baltimore, Carroll, Charles, Frederick and 8 more	87 min
Jun 12, 1:48 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Anne Arundel, Baltimore, Calvert, Caroline, Carroll and 14 more	6 hr

Nearby

Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in Maryland, 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.