Alert archive / Virginia / Mesoscale Discussions in 2012

Mesoscale Discussion 1619

July 26, 20125 states

The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2012, 9:06 PM EDT for 5 states. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Jul 26, 2012, 9:06 PM EDT (01:06 UTC)
Expired: Jul 26, 2012, 10:30 PM EDT
In force: 84 min
Issued by: the Storm Prediction Center

All 51 counties

Kent County, DE, New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Talbot County, MD, Atlantic County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Salem County, NJ, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Frederick County, VA, Greene County, VA, Loudoun County, VA, Madison County, VA, Page County, VA, Prince William County, VA, Rappahannock County, VA, Rockingham County, VA, Shenandoah County, VA, Stafford County, VA, Warren County, VA, Berkeley County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Pendleton County, WV

The radar

The Sterling radar (KLWX), 31 km from the middle of the area, began a volume at 01:08 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 00:00Z, 1.1 hours before the alert went out and 26 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: 3611 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1590 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 97 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 7.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 27, 1:08 PM EDT	Mesoscale Discussion	SPC	Albemarle, Amelia, Amherst, Appomattox, Bedford, Botetourt and 36 more	67 min
Jul 27, 1:54 PM EDT	Severe Thunderstorm Watch	SPC	Albemarle, Alleghany, Amelia, Amherst, Appomattox, Augusta and 100 more	8 hr
Jul 27, 4:52 PM EDT	Mesoscale Discussion	SPC	Albemarle, Amelia, Amherst, Appomattox, Bedford, Botetourt and 44 more	53 min
Jul 27, 7:50 PM EDT	Mesoscale Discussion	SPC	City of Chesapeake, City of Norfolk, City of Portsmouth, City of Suffolk, City of Virginia Beach	85 min
Jul 26, 8:55 PM EDT	Mesoscale Discussion	SPC	Wayne	65 min
Jul 27, 5:15 PM EDT	Mesoscale Discussion	SPC	Cabell, Mason	90 min
Jul 27, 7:11 PM EDT	Severe Thunderstorm Watch	SPC	Cabell, Lincoln, Mason, Putnam, Wayne	4 hr

Nearby

Mesoscale Discussions in Virginia, 2012 Mesoscale Discussions in Maryland, 2012 Mesoscale Discussions in New Jersey, 2012 Every mesoscale discussion 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.