Alert archive / Maryland / Mesoscale Discussions in 2011

Mesoscale Discussion 1788

July 29, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Jul 29, 2011, 6:17 PM EDT for 4 states. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Jul 29, 2011, 6:17 PM EDT (22:17 UTC)
Expired: Jul 29, 2011, 7:45 PM EDT
In force: 88 min
Issued by: the Storm Prediction Center

All 21 counties

New Castle County, DE, Allegany County, MD, Baltimore County, MD, Carroll County, MD, Cecil County, MD, City of Baltimore, MD, Frederick County, MD, Garrett County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Washington County, MD, Salem County, NJ, Berkeley County, WV, Hampshire County, WV, Jefferson County, WV, Marion County, WV, Mineral County, WV, Monongalia County, WV, Morgan County, WV, Preston County, WV

The radar

The Sterling radar (KLWX), 82 km from the middle of the area, began a volume at 22:17 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, 10.3 hours before the alert went out and 89 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: 529 J/kg
Mixed-layer CIN: -105 J/kg
Mixed-layer LCL: 1236 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 128 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Jul 29, 12:57 PM EDT	Mesoscale Discussion	SPC	Bergen, Essex, Hudson, Hunterdon, Morris, Passaic and 4 more	2 hr
Jul 29, 2:40 PM EDT	Severe Thunderstorm Watch	SPC	Bergen, Burlington, Camden, Essex, Gloucester, Hudson and 11 more	8 hr
Jul 29, 4:40 PM EDT	Mesoscale Discussion	SPC	Bergen, Burlington, Camden, Essex, Hudson, Hunterdon and 10 more	95 min
Jul 29, 5:03 PM EDT	Tornado Watch	SPC	Bergen, Passaic, Sussex	3 hr
Jul 29, 2:06 PM EDT	Mesoscale Discussion	SPC	Brooke, Hancock, Marshall, Monongalia, Ohio, Wetzel	84 min

Nearby

Mesoscale Discussions in Maryland, 2011 Mesoscale Discussions in West Virginia, 2011 Mesoscale Discussions in Delaware, 2011 Every mesoscale discussion in 2011

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.