Alert archive / Maryland / Tornado Watches in 2006

Tornado Watch 343

May 11, 200620 counties in Maryland; Lancaster County, York County, Pennsylvania; 10 counties in Virginia

The Storm Prediction Center issued this tornado watch at May 11, 2006, 6:19 PM EDT for 20 counties in Maryland; Lancaster County, York County, Pennsylvania; 10 counties in Virginia. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
May 11, 2006, 6:19 PM EDT (22:19 UTC)
Expired
May 11, 2006, 11:00 PM EDT
In force
5 hr
Issued by
the Storm Prediction Center
All 32 counties

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, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Lancaster County, PA, York County, PA, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Manassas, VA, City of Manassas Park, VA, Fairfax County, VA, Fauquier County, VA, Loudoun County, VA, Prince William County, VA

The radar

The Sterling radar (KLWX), 50 km from the middle of the area, began a volume at 22:19 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.

Warnings issued inside it

4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 11, 6:32 PM EDTTornado WarningLWXCharles28 min
May 11, 6:55 PM EDTTornado WarningLWXCharles, Prince George's35 min
May 11, 7:02 PM EDTTornado WarningLWXCharles28 min
May 11, 7:45 PM EDTSevere Thunderstorm WarningLWXMontgomery18 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.3 hours before the alert went out and 43 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 2006-05-11Temperature 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 2006-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 square meters per square second.19395878Sfc1 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
567 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
192 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 11, 10:23 AM EDTMesoscale DiscussionSPCAllegany, Garrett2 hr
May 11, 2:57 PM EDTMesoscale DiscussionSPCCharles, Montgomery, Prince George's, Saint Mary's2 hr
May 11, 5:46 PM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Calvert, Carroll, Cecil, Charles and 9 more59 min
May 11, 4:02 PM EDTTornado WatchSPCAlbemarle, Amelia, Brunswick, Caroline, Charles City, Chesterfield and 55 more6 hr

Nearby

Tornado Watches in Maryland, 2006Tornado Watches in Virginia, 2006Tornado Watches in Pennsylvania, 2006Every tornado watch in 2006

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.