Alert archive / Virginia / Mesoscale Discussions in 2018

Mesoscale Discussion 1175

July 27, 201811 states

The Storm Prediction Center issued this mesoscale discussion at Jul 27, 2018, 4:50 PM EDT for 11 states. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued: Jul 27, 2018, 4:50 PM EDT (20:50 UTC)
Expired: Jul 27, 2018, 5:45 PM EDT
In force: 55 min
Issued by: the Storm Prediction Center

All 192 counties

Kent County, DE, New Castle County, DE, Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Worcester County, MA, 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, Dorchester County, 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, Saint Mary's County, MD, Talbot County, MD, Washington County, MD, Androscoggin County, ME, Cumberland County, ME, Franklin County, ME, Kennebec County, ME, Oxford County, ME, Somerset County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Grafton County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH, Sullivan County, NH, Bergen County, NJ, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Essex County, NJ, Gloucester County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Passaic County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Albany County, NY, Bronx County, NY, Columbia County, NY, Delaware County, NY, Dutchess County, NY, Greene County, NY, Kings County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Rensselaer County, NY, Richmond County, NY, Rockland County, NY, Schenectady County, NY, Schoharie County, NY, Sullivan County, NY, Ulster County, NY, Westchester County, NY, Adams County, PA, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA, Pike County, PA, Schuylkill County, PA, Wayne County, PA, York County, PA, Albemarle County, VA, Alleghany County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Botetourt County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Covington, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Hopewell, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Petersburg, VA, City of Richmond, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, City of Williamsburg, VA, City of Winchester, VA, Clarke County, VA, Craig County, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Frederick County, VA, Gloucester County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, Henrico County, VA, Highland County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Loudoun County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Page County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA, Bennington County, VT, Windham County, VT, Windsor County, VT, Berkeley County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Morgan County, WV, Pendleton County, WV

The radar

The Philadelphia radar (KDIX), 112 km from the middle of the area, began a volume at 20:50 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

Brookhaven, NY (KOKX), launched 12:00Z, 8.8 hours before the alert went out and 164 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: 752 J/kg
Mixed-layer CIN: -30 J/kg
Mixed-layer LCL: 998 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 53 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.5

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 27, 12:59 PM EDT	Mesoscale Discussion	SPC		91 min
Jul 27, 1:17 PM EDT	Severe Thunderstorm Watch	SPC	Greater Bridgeport Planning Region, Capitol Planning Region, Northwest Hills Planning Region, Naugatuck Valley Planning Region	9 hr
Jul 27, 7:06 PM EDT	Mesoscale Discussion	SPC		54 min
Jul 27, 1:31 PM EDT	Severe Thunderstorm Watch	SPC	Androscoggin, Cumberland, Franklin, Oxford, York	8 hr
Jul 27, 2:06 PM EDT	Mesoscale Discussion	SPC	Aroostook, Penobscot, Piscataquis, Somerset	114 min
Jul 27, 1:28 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Charles, Frederick, Howard, Montgomery, Prince George's	62 min
Jul 27, 1:52 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 12 more	7 hr

Nearby

Mesoscale Discussions in Virginia, 2018 Mesoscale Discussions in Pennsylvania, 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.