Alert archive / Virginia / Excessive Heat Warnings in 2011

Excessive Heat Warning 2, NWS Baltimore/Washington

July 20, 201127 counties in Virginia; 11 counties in Maryland; Berkeley County, Jefferson County, Morgan County, West Virginia

NWS Baltimore/Washington issued this excessive heat warning at Jul 20, 2011, 3:19 PM EDT for 27 counties in Virginia; 11 counties in Maryland; Berkeley County, Jefferson County, Morgan County, West Virginia. It took effect at Jul 22, 2011, 10:00 AM EDT. It was in force for 11 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 20, 2011, 3:19 PM EDT (19:19 UTC)
In effect from: Jul 22, 2011, 10:00 AM EDT
Expired: Jul 22, 2011, 9:21 PM EDT
In force: 11 hr
Issued by: NWS Baltimore/Washington

All 41 counties

Allegany County, MD, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Carroll County, MD, Charles County, MD, City of Baltimore, MD, Frederick County, MD, Prince George's County, MD, Saint Mary's County, MD, Washington County, MD, Arlington 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 Harrisonburg, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Frederick County, VA, Greene County, VA, King George County, VA, Madison County, VA, Nelson County, VA, Orange County, VA, Page County, VA, Rappahannock County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Berkeley County, WV, Jefferson County, WV, Morgan County, WV

The radar

The Sterling radar (KLWX), 34 km from the middle of the area, began a volume at 19:19 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, 7.3 hours before the alert went out and 38 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: 1142 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 675 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 9 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 excessive heat 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 excessive heat warning went out at Jul 20, 10:36 AM EDT, 4 hours 43 minutes earlier.

Area forecast discussion, Jul 20, 10:36 AM EDT, 4 hours 43 minutes before

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Hazardous weather outlook, Jul 20, 3:23 AM EDT, 11 hours 56 minutes before

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In the hours before

Special weather statement, Jul 20, 1:13 PM EDT, 2 hours 6 minutes before

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Special weather statement, Jul 20, 2:50 PM EDT, 29 minutes before

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Special weather statement, Jul 20, 2:54 PM EDT, 25 minutes before

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Special weather statement, Jul 20, 3:05 PM EDT, 14 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
Jul 19, 8:18 PM EDT	Special Marine Warning	LWX		99 min
Jul 19, 9:11 PM EDT	Special Marine Warning	LWX		49 min
Jul 19, 10:17 PM EDT	Special Marine Warning	LWX		33 min
Jul 19, 10:30 PM EDT	Special Weather Statement	LWX	King George	30 min
Jul 19, 10:37 PM EDT	Severe Thunderstorm Warning	LWX	King George	23 min
Jul 20, 1:13 PM EDT	Special Weather Statement	LWX	Albemarle, Greene, Madison, Nelson, Rappahannock, City of Charlottesville	62 min
Jul 20, 2:50 PM EDT	Special Weather Statement	LWX	Augusta, Highland, City of Staunton	55 min
Jul 20, 2:54 PM EDT	Special Weather Statement	LWX	Madison	66 min
Jul 20, 3:19 PM EDT	Excessive Heat Warning	LWX	Arlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 21 more	31 hr
Jul 20, 6:29 PM EDT	Special Weather Statement	LWX	City of Buena Vista	61 min
Jul 20, 6:49 PM EDT	Areal Flood Advisory	LWX	Augusta, Nelson	84 min
Jul 19, 8:02 PM EDT	Severe Thunderstorm Warning	LWX	Calvert, Saint Mary's	43 min
Jul 19, 8:45 PM EDT	Special Weather Statement	LWX	Charles, Saint Mary's	45 min
Jul 19, 10:14 PM EDT	Special Weather Statement	LWX	Baltimore	31 min
Jul 19, 11:17 PM EDT	Special Weather Statement	LWX	Saint Mary's	28 min
Jul 20, 3:05 PM EDT	Special Weather Statement	LWX	Prince George's	55 min
Jul 20, 4:14 PM EDT	Special Weather Statement	LWX	Berkeley	61 min
Jul 20, 4:45 PM EDT	Areal Flood Advisory	LWX	Berkeley, Morgan	48 min

Nearby

Excessive Heat Warnings in Virginia, 2011 Excessive Heat Warnings in Maryland, 2011 Excessive Heat Warnings in West Virginia, 2011 Every excessive heat warning 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.