Alert archive / Virginia / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 270, NWS Wakefield, VA

August 11, 20094 counties in Virginia

NWS Wakefield, VA issued this severe thunderstorm warning at Aug 11, 2009, 7:40 PM EDT for 4 counties in Virginia. It was in force for 50 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 11, 2009, 7:40 PM EDT (23:40 UTC)
Expired: Aug 11, 2009, 8:30 PM EDT
In force: 50 min
Issued by: NWS Wakefield, VA
Area: Storm-based polygon

Counties Gloucester County, VA, King and Queen County, VA, King William County, VA, Middlesex County, VA

The radar

The Norfolk radar (KAKQ), 72 km from the middle of the area, began a volume at 23:40 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, 11.7 hours before the alert went out and 215 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: 93 J/kg
Mixed-layer CIN: -161 J/kg
Mixed-layer LCL: 1076 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -52 m²/s²
0-3 km storm-relative helicity: 27 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Wakefield, VA wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 11, 4:05 PM EDT, 3 hours 35 minutes earlier.

Area forecast discussion, Aug 11, 4:05 PM EDT, 3 hours 35 minutes before

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Hazardous weather outlook, Aug 11, 3:28 PM EDT, 4 hours 12 minutes before

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In the hours before

Special weather statement, Aug 11, 5:39 PM EDT, 2 hours 1 minute before

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Special weather statement, Aug 11, 5:53 PM EDT, 1 hour 47 minutes before

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Special weather statement, Aug 11, 6:18 PM EDT, 1 hour 22 minutes before

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Special weather statement, Aug 11, 6:32 PM EDT, 1 hour 8 minutes before

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Special weather statement, Aug 11, 7:35 PM EDT, 5 minutes before

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The office that day

Everything else NWS Wakefield, VA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 11, 7:23 PM EDT	Severe Thunderstorm Warning	AKQ	Lancaster, Northumberland	52 min
Aug 11, 7:27 PM EDT	Special Marine Warning	AKQ		63 min

Nearby

Severe Thunderstorm Warnings in Virginia, 2009 Every severe thunderstorm warning 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.