Alert archive / Virginia / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 239, NWS Baltimore/Washington

August 9, 2007Page County, Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Aug 9, 2007, 1:47 PM EDT for Page County, Virginia. It was in force for 43 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 9, 2007, 1:47 PM EDT (17:47 UTC)
Expired: Aug 9, 2007, 2:30 PM EDT
In force: 43 min
Issued by: NWS Baltimore/Washington
Area: Counties, with a storm outline in the text

County Page County, VA

The radar

The Sterling radar (KLWX), 95 km from the middle of the area, began a volume at 17:48 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, 5.8 hours before the alert went out and 101 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: 547 J/kg
Mixed-layer CIN: -121 J/kg
Mixed-layer LCL: 1213 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 40 m²/s²
0-3 km storm-relative helicity: 117 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.4

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 Baltimore/Washington wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 9, 10:13 AM EDT, 3 hours 34 minutes earlier.

Area forecast discussion, Aug 9, 10:13 AM EDT, 3 hours 34 minutes before

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Hazardous weather outlook, Aug 9, 10:39 AM EDT, 3 hours 8 minutes before

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In the hours before

Special weather statement, Aug 9, 10:40 AM EDT, 3 hours 7 minutes before

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Local storm report, Aug 9, 11:46 AM EDT, 2 hours 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1146 AM EDT THU AUG 09 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1130 AM     TSTM WND DMG     HALFWAY                 39.61N 77.77W
08/09/2007                   WASHINGTON         MD   EMERGENCY MNGR

            POWER LINE DOWN IN HALFWAY.

&&

SAR

Local storm report, Aug 9, 12:28 PM EDT, 1 hour 19 minutes before

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Special weather statement, Aug 9, 1:11 PM EDT, 36 minutes before

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Special weather statement, Aug 9, 1:16 PM EDT, 31 minutes before

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Special weather statement, Aug 9, 1:17 PM EDT, 30 minutes before

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The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 9, 12:16 PM EDT	Special Marine Warning	LWX		119 min
Aug 9, 12:53 PM EDT	Special Marine Warning	LWX		86 min
Aug 9, 1:19 PM EDT	Severe Thunderstorm Warning	LWX	Rappahannock	41 min
Aug 9, 1:47 PM EDT	Special Marine Warning	LWX		118 min
Aug 9, 2:12 PM EDT	Severe Thunderstorm Warning	LWX	Prince William	48 min
Aug 9, 2:28 PM EDT	Severe Thunderstorm Warning	LWX	Rockingham	35 min
Aug 9, 2:53 PM EDT	Severe Thunderstorm Warning	LWX	Stafford	67 min
Aug 9, 3:02 PM EDT	Severe Thunderstorm Warning	LWX	Prince William	28 min
Aug 9, 3:07 PM EDT	Special Marine Warning	LWX		95 min
Aug 9, 4:26 PM EDT	Severe Thunderstorm Warning	LWX	Albemarle	49 min
Aug 9, 5:04 PM EDT	Tornado Warning	LWX	Albemarle	20 min
Aug 9, 7:01 PM EDT	Special Marine Warning	LWX		102 min
Aug 9, 10:47 AM EDT	Severe Thunderstorm Warning	LWX	Washington	73 min
Aug 9, 11:18 AM EDT	Severe Thunderstorm Warning	LWX	Carroll, Frederick	72 min
Aug 9, 3:01 PM EDT	Severe Thunderstorm Warning	LWX	Saint Mary's	44 min
Aug 9, 3:16 PM EDT	Severe Thunderstorm Warning	LWX	Charles	44 min
Aug 9, 6:51 PM EDT	Severe Thunderstorm Warning	LWX	Carroll, Frederick	44 min
Aug 9, 6:11 PM EDT	Severe Thunderstorm Warning	LWX	Grant	64 min
Aug 9, 7:13 PM EDT	Severe Thunderstorm Warning	LWX	Hardy	37 min

Nearby

Severe Thunderstorm Warnings in Virginia, 2007 Every severe thunderstorm warning in 2007

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.