Alert archive / Maryland / Mesoscale Discussions in 2020

Mesoscale Discussion 1027

June 27, 20204 states

The Storm Prediction Center issued this mesoscale discussion at Jun 27, 2020, 5:30 PM EDT for 4 states. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Jun 27, 2020, 5:30 PM EDT (21:30 UTC)
Expired: Jun 27, 2020, 6:30 PM EDT
In force: 60 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

All 22 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Anne Arundel County, MD, Calvert County, MD, Caroline County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Harford County, MD, Kent County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Talbot County, MD, Wicomico County, MD, Cumberland County, NJ, Salem County, NJ, Arlington County, VA, City of Alexandria, VA, Stafford County, VA

The radar

The Dover AFB radar (KDOX), 75 km from the middle of the area, began a volume at 21:30 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, 9.5 hours before the alert went out and 95 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: -198 J/kg
Mixed-layer LCL: 1545 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 173 m²/s²
0-3 km storm-relative helicity: 160 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 27, 12:34 PM EDT	Mesoscale Discussion	SPC	Bergen, Burlington, Essex, Hudson, Hunterdon, Mercer and 9 more	2 hr
Jun 27, 3:16 PM EDT	Severe Thunderstorm Watch	SPC	Atlantic, Burlington, Camden, Gloucester, Hunterdon, Mercer and 4 more	5 hr
Jun 27, 4:15 PM EDT	Mesoscale Discussion	SPC	Hunterdon, Mercer, Middlesex, Monmouth, Ocean, Somerset	90 min

Nearby

Mesoscale Discussions in Maryland, 2020 Mesoscale Discussions in Delaware, 2020 Mesoscale Discussions in 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.