Alert archive / Virginia / Heat Advisories in 2011

Heat Advisory 2, NWS Blacksburg, VA

July 20, 20114 counties in Virginia; Caswell County, Rockingham County, North Carolina

NWS Blacksburg, VA issued this heat advisory at Jul 20, 2011, 2:21 PM EDT for 4 counties in Virginia; Caswell County, Rockingham County, North Carolina. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued: Jul 20, 2011, 2:21 PM EDT (18:21 UTC)
Expired: Jul 20, 2011, 8:00 PM EDT
In force: 6 hr
Issued by: NWS Blacksburg, VA

Counties Caswell County, NC, Rockingham County, NC, Charlotte County, VA, City of Danville, VA, Halifax County, VA, Pittsylvania County, VA

The radar

The Roanoke radar (KFCX), 100 km from the middle of the area, began a volume at 18:23 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

Roanoke, VA (KRNK), launched 12:00Z, 6.4 hours before the alert went out and 64 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: 975 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 578 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 28 m²/s²
0-3 km storm-relative helicity: 11 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 20, 1:30 PM EDT, 51 minutes earlier.

Area forecast discussion, Jul 20, 1:30 PM EDT, 51 minutes before

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Hazardous weather outlook, Jul 20, 3:22 AM EDT, 10 hours 59 minutes before

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In the hours before

Local storm report, Jul 20, 9:28 AM EDT, 4 hours 53 minutes before

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Local storm report, Jul 20, 11:51 AM EDT, 2 hours 30 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
1151 AM EDT WED JUL 20 2011

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

0523 PM     TSTM WND DMG     3 SSW DANVILLE CITY     36.55N 79.44W
07/19/2011                   CITY OF DANVILLE   VA   PUBLIC

            POWER AND CABLE LINES DOWN ON HOLLAND ROAD JUST NORTH OF
            THE NC BORDER.

&&

CHENARD

Special weather statement, Jul 20, 1:24 PM EDT, 57 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
124 PM EDT WED JUL 20 2011

NCZ002-018-019-201815-
ALLEGHANY NC-WATAUGA NC-WILKES NC-
124 PM EDT WED JUL 20 2011

...THUNDERSTORMS WITH HEAVY RAINFALL WILL AFFECT ALLEGHANY...WATAUGA
AND WILKES COUNTIES...

AT 122 PM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM TRAPHILL
TO 9 MILES SOUTH OF DEEP GAP...MOVING SOUTHEAST AT 5 MPH.

WIND GUSTS TO 30 MPH ARE POSSIBLE WITH THESE STORMS. VERY HEAVY RAIN
WILL FALL FROM THESE STORMS...AND WILL CAUSE WATER TO POND ON ROADS
AND QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS. EXPECT FREQUENT
CLOUD TO GROUND LIGHTNING FROM THESE STORMS. DO NOT STAY IN THE OPEN
OR SEEK SHELTER UNDER TREES WHEN LIGHTNING THREATENS...MOVE INDOORS
WHEN A THUNDERSTORM APPROACHES.

THESE STORMS WILL BE NEAR ROARING GAP AROUND 135 PM...TRAPHILL AROUND
140 PM...DOCKERY AROUND 150 PM...MULBERRY...AND MILLERS CREEK AROUND
155 PM...MULBERRY AROUND 200 PM...HAYS...ELKVILLE AND AND BUCK AROUND
205 PM.

LAT...LON 3605 8140 3607 8142 3607 8144 3609 8149
      3609 8152 3611 8155 3611 8161 3613 8162
      3628 8137 3650 8105 3631 8086 3600 8134

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 2:21 PM EDT	Heat Advisory	RNK	Alleghany, Amherst, Appomattox, Bedford, Botetourt, Buckingham and 17 more	30 hr
Jul 20, 4:39 PM EDT	Special Weather Statement	RNK	Alleghany, City of Covington	36 min
Jul 20, 5:11 PM EDT	Special Weather Statement	RNK	Rockbridge, City of Lexington	34 min
Jul 20, 1:24 PM EDT	Special Weather Statement	RNK	Wilkes	51 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.