Alert archive / Virginia / Heat Advisories in 2011

Heat Advisory 4, NWS Blacksburg, VA

July 21, 201120 counties in Virginia; 6 counties in North Carolina

NWS Blacksburg, VA issued this heat advisory at Jul 21, 2011, 3:28 PM EDT for 20 counties in Virginia; 6 counties in North Carolina. It took effect at Jul 22, 2011, 10:00 AM EDT. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued: Jul 21, 2011, 3:28 PM EDT (19:28 UTC)
In effect from: Jul 22, 2011, 10:00 AM EDT
Expired: Jul 22, 2011, 8:00 PM EDT
In force: 10 hr
Issued by: NWS Blacksburg, VA

All 26 counties

Caswell County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Wilkes County, NC, Yadkin County, NC, Alleghany County, VA, Amherst County, VA, Bedford County, VA, Botetourt County, VA, Campbell County, VA, City of Buena Vista, VA, City of Covington, VA, City of Danville, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Roanoke, VA, City of Salem, VA, Franklin County, VA, Halifax County, VA, Henry County, VA, Patrick County, VA, Pittsylvania County, VA, Roanoke County, VA, Rockbridge County, VA

The radar

The Roanoke radar (KFCX), 43 km from the middle of the area, began a volume at 19:30 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 7.5 hours before the alert went out and 107 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: 1698 J/kg
Mixed-layer CIN: -56 J/kg
Mixed-layer LCL: 1066 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: -12 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Blacksburg, VA wrote its last area forecast discussion before this heat advisory went out at Jul 21, 1:41 PM EDT, 1 hour 47 minutes earlier.

Area forecast discussion, Jul 21, 1:41 PM EDT, 1 hour 47 minutes before

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Hazardous weather outlook, Jul 21, 11:12 AM EDT, 4 hours 16 minutes before

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In the hours before

Special weather statement, Jul 21, 3:27 PM EDT, 1 minute before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 12:22 AM EDT	Special Weather Statement	RNK	Appomattox, City of Lynchburg	38 min
Jul 21, 1:49 AM EDT	Special Weather Statement	RNK	City of Lynchburg	41 min
Jul 21, 3:28 PM EDT	Excessive Heat Warning	RNK	Appomattox, Buckingham, Charlotte	29 hr
Jul 21, 3:27 PM EDT	Special Weather Statement	RNK	Watauga	63 min
Jul 21, 3:55 PM EDT	Special Weather Statement	RNK	Person	65 min

Nearby

Heat Advisories in Virginia, 2011 Heat Advisories in North Carolina, 2011 Every heat advisory 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.