Alert archive / Virginia / Excessive Heat Warnings in 2012

Excessive Heat Warning 4, NWS Baltimore/Washington

July 6, 201219 counties in Virginia; 10 counties in Maryland; Berkeley County, Jefferson County, West Virginia

NWS Baltimore/Washington issued this excessive heat warning at Jul 6, 2012, 1:49 PM EDT for 19 counties in Virginia; 10 counties in Maryland; Berkeley County, Jefferson County, West Virginia. It took effect at Jul 7, 2012, 11:00 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 6, 2012, 1:49 PM EDT (17:49 UTC)
In effect from: Jul 7, 2012, 11:00 AM EDT
Expired: Jul 7, 2012, 9:35 PM EDT
In force: 11 hr
Issued by: NWS Baltimore/Washington

All 31 counties

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, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Greene County, VA, King George County, VA, Madison County, VA, Nelson County, VA, Orange County, VA, Rappahannock County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Berkeley County, WV, Jefferson County, WV

The radar

The Sterling radar (KLWX), 25 km from the middle of the area, began a volume at 17:53 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 24 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: 697 J/kg
Mixed-layer CIN: -96 J/kg
Mixed-layer LCL: 1152 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: -24 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 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 6, 9:45 AM EDT, 4 hours 4 minutes earlier.

Area forecast discussion, Jul 6, 9:45 AM EDT, 4 hours 4 minutes before

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Hazardous weather outlook, Jul 6, 9:15 AM EDT, 4 hours 34 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 5, 9:20 PM EDT	Excessive Heat Watch	LWX	Arlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 21 more	16 hr
Jul 6, 3:22 AM EDT	Heat Advisory	LWX	Arlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 17 more	17 hr
Jul 6, 1:49 PM EDT	Heat Advisory	LWX	Clarke, Fauquier, Frederick, Page, Rappahannock, Rockingham and 6 more	32 hr

Nearby

Excessive Heat Warnings in Virginia, 2012 Excessive Heat Warnings in Maryland, 2012 Excessive Heat Warnings in West Virginia, 2012 Every excessive heat warning in 2012

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.