Alert archive / Virginia / Mesoscale Discussions in 2017

Mesoscale Discussion 1305

July 13, 2017Kent County, Sussex County, Delaware; 14 counties in Maryland; 17 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jul 13, 2017, 3:03 PM EDT for Kent County, Sussex County, Delaware; 14 counties in Maryland; 17 counties in Virginia. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued: Jul 13, 2017, 3:03 PM EDT (19:03 UTC)
Expired: Jul 13, 2017, 4:00 PM EDT
In force: 57 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 33 counties

Kent County, DE, Sussex County, DE, Anne Arundel County, MD, Calvert County, MD, Caroline County, MD, Cecil County, MD, Charles County, MD, Dorchester County, MD, Kent County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Arlington County, VA, Caroline County, VA, City of Alexandria, VA, City of Fredericksburg, VA, Essex County, VA, Hanover County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Northumberland County, VA, Orange County, VA, Richmond County, VA, Spotsylvania County, VA, Stafford County, VA, Westmoreland County, VA

The radar

The Sterling radar (KLWX), 90 km from the middle of the area, began a volume at 19:06 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, 7.1 hours before the alert went out and 83 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: 135 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 1715 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 49 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 13, 11:09 AM EDT	Mesoscale Discussion	SPC	Kent, New Castle	2 hr

Nearby

Mesoscale Discussions in Virginia, 2017 Mesoscale Discussions in Maryland, 2017 Mesoscale Discussions in Delaware, 2017 Every mesoscale discussion in 2017

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.