Alert archive / Maryland / Mesoscale Discussions in 2007

Mesoscale Discussion 1696

August 9, 20074 states

The Storm Prediction Center issued this mesoscale discussion at Aug 9, 2007, 12:35 PM EDT for 4 states. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: Aug 9, 2007, 12:35 PM EDT (16:35 UTC)
Expired: Aug 9, 2007, 2:00 PM EDT
In force: 85 min
Issued by: the Storm Prediction Center

All 24 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Cecil County, MD, City of Baltimore, MD, Dorchester County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Cumberland County, NJ, Salem County, NJ, Accomack County, VA, Northumberland County, VA

The radar

The Dover AFB radar (KDOX), 73 km from the middle of the area, began a volume at 16:34 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 574Aug 9, 12:50 PM EDT

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 4.6 hours before the alert went out and 52 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: 30 J/kg
Mixed-layer CIN: -330 J/kg
Mixed-layer LCL: 1529 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -22 m²/s²
0-3 km storm-relative helicity: 73 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
Aug 9, 12:48 PM EDT	Severe Thunderstorm Watch	SPC	Kent, New Castle, Sussex	3 hr
Aug 9, 7:23 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	67 min
Aug 9, 8:47 AM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Carroll, Cecil, Frederick, Harford and 6 more	58 min
Aug 9, 9:47 AM EDT	Severe Thunderstorm Watch	SPC	Allegany, Anne Arundel, Baltimore, Carroll, Frederick, Harford and 5 more	6 hr
Aug 9, 1:22 PM EDT	Severe Thunderstorm Watch	SPC	Garrett	7 hr
Aug 9, 2:25 PM EDT	Mesoscale Discussion	SPC	Calvert, Charles, Dorchester, Saint Mary's, Somerset, Wicomico	2 hr
Aug 9, 2:41 PM EDT	Mesoscale Discussion	SPC	Allegany, Anne Arundel, Calvert, Charles, Dorchester, Frederick and 9 more	94 min

Nearby

Mesoscale Discussions in Maryland, 2007 Mesoscale Discussions in Delaware, 2007 Mesoscale Discussions in New Jersey, 2007 Every mesoscale discussion in 2007

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.