Alert archive / Virginia / Mesoscale Discussions in 2014

Mesoscale Discussion 1830

October 7, 2014Charles County, Maryland; 29 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Oct 7, 2014, 9:17 PM EDT for Charles County, Maryland; 29 counties in Virginia. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Oct 7, 2014, 9:17 PM EDT (01:17 UTC)
Expired: Oct 7, 2014, 10:45 PM EDT
In force: 88 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 30 counties

Charles County, MD, Amelia County, VA, Appomattox County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charlotte County, VA, Chesterfield County, VA, City of Fredericksburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Richmond, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fluvanna County, VA, Goochland County, VA, Hanover County, VA, Henrico County, VA, King George County, VA, King William County, VA, Louisa County, VA, Nottoway County, VA, Orange County, VA, Powhatan County, VA, Prince Edward County, VA, Prince William County, VA, Spotsylvania County, VA, Stafford County, VA

The radar

The Sterling radar (KLWX), 106 km from the middle of the area, began a volume at 01:20 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

Roanoke, VA (KRNK), launched 00:00Z, 1.3 hours before the alert went out and 173 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: 44 J/kg
Mixed-layer CIN: -38 J/kg
Mixed-layer LCL: 671 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 488 m²/s²
0-3 km storm-relative helicity: 524 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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
Oct 7, 11:06 PM EDT	Mesoscale Discussion	SPC	Caroline, Dorchester, Somerset, Talbot, Wicomico	84 min

Nearby

Mesoscale Discussions in Virginia, 2014 Mesoscale Discussions in Maryland, 2014 Every mesoscale discussion in 2014

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.