Alert archive / Maryland / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 284, NWS Baltimore/Washington

August 11, 20124 counties in Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Aug 11, 2012, 5:20 PM EDT for 4 counties in Maryland. It was in force for 40 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 11, 2012, 5:20 PM EDT (21:20 UTC)
Expired
Aug 11, 2012, 6:00 PM EDT
In force
40 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon

Counties Calvert County, MD, Charles County, MD, Prince George's County, MD, Saint Mary's County, MD

The radar

The Sterling radar (KLWX), 83 km from the middle of the area, began a volume at 21:21 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, 9.3 hours before the alert went out and 76 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2012-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2012-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -38 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
0 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
-38 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

Hazardous weather outlook, Aug 10, 7:40 PM EDT, 21 hours 40 minutes before
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The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 10, 9:33 PM EDTSpecial Weather StatementLWXSpotsylvania42 min
Aug 10, 10:48 PM EDTSpecial Weather StatementLWXCity of Charlottesville42 min
Aug 11, 1:30 AM EDTSpecial Weather StatementLWXOrange30 min
Aug 11, 2:03 AM EDTSpecial Weather StatementLWXStafford, City of Fredericksburg27 min
Aug 11, 3:25 PM EDTSpecial Marine WarningLWX2 hr
Aug 11, 4:34 PM EDTSpecial Marine WarningLWX116 min
Aug 11, 4:38 PM EDTSpecial Marine WarningLWX2 hr
Aug 11, 5:57 PM EDTSpecial Marine WarningLWX93 min
Aug 11, 6:39 PM EDTSpecial Marine WarningLWX79 min
Aug 11, 7:06 PM EDTSpecial Marine WarningLWX73 min
Aug 11, 5:11 PM EDTSpecial Weather StatementLWXCharles34 min
Aug 11, 6:31 PM EDTSpecial Weather StatementLWXAnne Arundel29 min
Aug 11, 6:43 PM EDTSpecial Weather StatementLWXAnne Arundel32 min
Aug 11, 7:04 PM EDTSpecial Weather StatementLWXBaltimore, City of Baltimore26 min
Aug 11, 7:25 PM EDTSpecial Weather StatementLWXHarford35 min
Aug 11, 7:51 PM EDTSpecial Weather StatementLWXHarford24 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2012Every severe thunderstorm warning in 2012

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.