Alert archive / Virginia / Winter Storm Warnings in 2011

Winter Storm Warning 6, NWS Baltimore/Washington

October 29, 20116 counties in Virginia; Carroll County, Frederick County, Maryland

NWS Baltimore/Washington issued this winter storm warning at Oct 29, 2011, 5:30 AM EDT for 6 counties in Virginia; Carroll County, Frederick County, Maryland. It took effect at Oct 29, 2011, 8:00 AM EDT. It was in force for 10 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Oct 29, 2011, 5:30 AM EDT (09:30 UTC)
In effect from
Oct 29, 2011, 8:00 AM EDT
Expired
Oct 29, 2011, 6:00 PM EDT
In force
10 hr
Issued by
NWS Baltimore/Washington

Counties Carroll County, MD, Frederick County, MD, City of Charlottesville, VA, Fauquier County, VA, Greene County, VA, Madison County, VA, Nelson County, VA, Rappahannock County, VA

The radar

The Sterling radar (KLWX), 63 km from the middle of the area, began a volume at 09:32 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 00:00Z, 9.5 hours before the alert went out and 68 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 00:00Z on 2011-10-29Temperature 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 00:00Z on 2011-10-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 square meters per square second.1939587897117Sfc1 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
1309 m above ground
0-6 km bulk shear
63 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
308 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 28, 9:23 PM EDTCoastal Flood AdvisoryLWXArlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church3 hr
Oct 29, 5:02 AM EDTSmall Craft AdvisoryLWX3 hr
Oct 29, 5:30 AM EDTWinter Weather AdvisoryLWXFairfax, Fauquier, City of Fairfax15 hr
Oct 29, 8:17 AM EDTCoastal Flood AdvisoryLWXArlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church4 hr
Oct 29, 10:32 AM EDTFreeze WarningLWXArlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 21 more22 hr

Nearby

Winter Storm Warnings in Virginia, 2011Winter Storm Warnings in Maryland, 2011Every winter storm warning 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.