Alert archive / Virginia / Mesoscale Discussions in 2009

Mesoscale Discussion 920

June 2, 20095 states

The Storm Prediction Center issued this mesoscale discussion at Jun 2, 2009, 1:31 PM EDT for 5 states. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Jun 2, 2009, 1:31 PM EDT (17:31 UTC)
Expired: Jun 2, 2009, 3:00 PM EDT
In force: 89 min
Issued by: the Storm Prediction Center

All 57 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Salem County, NJ, Adams County, PA, Chester County, PA, Cumberland County, PA, Delaware County, PA, Lancaster County, PA, Philadelphia County, PA, York County, PA, Arlington County, VA, Caroline County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Manassas, VA, City of Manassas Park, VA, Culpeper County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, King George County, VA, Lancaster County, VA, Loudoun County, VA, Northumberland County, VA, Orange County, VA, Prince William County, VA, Richmond County, VA, Spotsylvania County, VA, Stafford County, VA, Westmoreland County, VA

The radar

The Dover AFB radar (KDOX), 83 km from the middle of the area, began a volume at 17:34 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.

Severe Thunderstorm Watch 322Jun 2, 1:55 PM EDT

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 5.5 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1348 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 63 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 2, 1:58 PM EDT	Severe Thunderstorm Watch	SPC	Kent, New Castle, Sussex	6 hr
Jun 2, 4:18 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	87 min
Jun 2, 6:47 PM EDT	Mesoscale Discussion	SPC	Calvert, Charles, Dorchester, Saint Mary's, Somerset	58 min
Jun 1, 9:32 PM EDT	Mesoscale Discussion	SPC	Beaver, Butler, Crawford, Lawrence, Mercer	58 min
Jun 2, 4:47 PM EDT	Mesoscale Discussion	SPC	Greene, Washington	88 min
Jun 2, 7:13 PM EDT	Mesoscale Discussion	SPC	Greene	62 min

Nearby

Mesoscale Discussions in Virginia, 2009 Mesoscale Discussions in Maryland, 2009 Mesoscale Discussions in Pennsylvania, 2009 Every mesoscale discussion in 2009

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.