Alert archive / Virginia / Mesoscale Discussions in 2020

Mesoscale Discussion 994

June 25, 20204 states

The Storm Prediction Center issued this mesoscale discussion at Jun 25, 2020, 1:48 PM EDT for 4 states. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jun 25, 2020, 1:48 PM EDT (17:48 UTC)
Expired: Jun 25, 2020, 3:45 PM EDT
In force: 117 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

All 68 counties

Anne Arundel County, MD, Baltimore County, MD, Carroll County, MD, Charles County, MD, City of Baltimore, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Montgomery County, MD, Prince George's County, MD, Washington County, MD, Adams County, PA, Albemarle County, VA, Amherst County, VA, Arlington County, VA, Augusta County, VA, Buckingham County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Richmond, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Frederick County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, Henrico County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Nelson County, VA, New Kent County, VA, Orange County, VA, Page County, VA, Powhatan County, VA, Prince William County, VA, Rappahannock County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA, Berkeley County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Morgan County, WV

The radar

The Sterling radar (KLWX), 13 km from the middle of the area, began a volume at 17:49 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 20 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: 2 J/kg
Mixed-layer CIN: -176 J/kg
Mixed-layer LCL: 1731 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 68 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
Jun 25, 6:09 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 14 more	96 min
Jun 25, 5:48 PM EDT	Mesoscale Discussion	SPC	Charlotte, Halifax, Henry, Lunenburg, Mecklenburg, Nottoway and 3 more	87 min

Nearby

Mesoscale Discussions in Virginia, 2020 Mesoscale Discussions in Maryland, 2020 Mesoscale Discussions in West Virginia, 2020 Every mesoscale discussion in 2020

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.