Alert archive / Virginia / Mesoscale Discussions in 2018

Mesoscale Discussion 415

May 14, 2018Somerset County, Maryland; 46 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at May 14, 2018, 5:37 PM EDT for Somerset County, Maryland; 46 counties in Virginia. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: May 14, 2018, 5:37 PM EDT (21:37 UTC)
Expired: May 14, 2018, 6:30 PM EDT
In force: 53 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 47 counties

Somerset County, MD, Accomack County, VA, Albemarle County, VA, Amelia County, VA, Appomattox County, VA, Buckingham County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Hampton, VA, City of Hopewell, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Richmond, VA, City of Virginia Beach, VA, City of Waynesboro, VA, City of Williamsburg, VA, Cumberland County, VA, Essex County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland County, VA, Hanover County, VA, Henrico County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Mathews County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Powhatan County, VA, Prince George County, VA, Richmond County, VA, Surry County, VA, Westmoreland County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 101 km from the middle of the area, began a volume at 21:40 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 92May 14, 6:10 PM EDT

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.6 hours before the alert went out and 138 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 828 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 138 m²/s²
0-3 km storm-relative helicity: 136 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
May 14, 11:56 AM EDT	Mesoscale Discussion	SPC	Allegany, Carroll, Frederick, Garrett, Howard, Montgomery and 1 more	64 min
May 14, 12:29 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 9 more	9 hr
May 14, 3:26 PM EDT	Mesoscale Discussion	SPC	Allegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 10 more	2 hr
May 14, 6:11 PM EDT	Severe Thunderstorm Watch	SPC	Dorchester, Somerset, Wicomico, Worcester	4 hr
May 14, 7:22 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Calvert, Charles, Howard, Prince George's, Saint Mary's and 1 more	53 min

Nearby

Mesoscale Discussions in Virginia, 2018 Mesoscale Discussions in Maryland, 2018 Every mesoscale discussion in 2018

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.