Alert archive / Virginia / Mesoscale Discussions in 2009

Mesoscale Discussion 893

May 29, 20095 states

The Storm Prediction Center issued this mesoscale discussion at May 29, 2009, 4:30 PM EDT for 5 states. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: May 29, 2009, 4:30 PM EDT (20:30 UTC)
Expired: May 29, 2009, 5:30 PM EDT
In force: 60 min
Issued by: the Storm Prediction Center

All 77 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, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Ocean County, NJ, Salem County, NJ, Chester County, PA, Delaware County, PA, Lancaster County, PA, Philadelphia County, PA, York County, PA, Albemarle County, VA, Amherst County, VA, Arlington County, VA, Buckingham County, VA, Caroline County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Richmond, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northumberland County, VA, Orange County, VA, Powhatan County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Spotsylvania County, VA, Stafford County, VA, Westmoreland County, VA

The radar

The Sterling radar (KLWX), 60 km from the middle of the area, began a volume at 20:31 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, 8.5 hours before the alert went out and 133 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: 4 J/kg
Mixed-layer CIN: -283 J/kg
Mixed-layer LCL: 620 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 58 m²/s²
0-3 km storm-relative helicity: 139 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 29, 12:20 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle	55 min
May 29, 1:26 PM EDT	Severe Thunderstorm Watch	SPC	Kent, New Castle, Sussex	8 hr
May 29, 6:20 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	55 min
May 29, 2:22 PM EDT	Mesoscale Discussion	SPC	Brunswick, Charlotte, Greensville, Halifax, Lunenburg, Mecklenburg and 6 more	23 min
May 29, 2:41 PM EDT	Severe Thunderstorm Watch	SPC	Amelia, Appomattox, Brunswick, Campbell, Charles City, Charlotte and 37 more	8 hr
May 29, 6:01 PM EDT	Mesoscale Discussion	SPC	Amelia, Appomattox, Brunswick, Campbell, Charles City, Charlotte and 37 more	59 min

Nearby

Mesoscale Discussions in Virginia, 2009 Mesoscale Discussions in Maryland, 2009 Mesoscale Discussions in New Jersey, 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.