Alert archive / Virginia / Winter Weather Advisories in 2017

Winter Weather Advisory 13, NWS Blacksburg, VA

December 8, 201712 counties in Virginia

NWS Blacksburg, VA issued this winter weather advisory at Dec 8, 2017, 2:34 PM EST for 12 counties in Virginia. It took effect at Dec 8, 2017, 4:00 PM EST. It was in force for 24 hr.

The area

The counties it named.

The facts

Issued
Dec 8, 2017, 2:34 PM EST (19:34 UTC)
In effect from
Dec 8, 2017, 4:00 PM EST
Expired
Dec 9, 2017, 3:47 PM EST
In force
24 hr
Issued by
NWS Blacksburg, VA

Counties Botetourt County, VA, City of Buena Vista, VA, City of Lexington, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, Montgomery County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Smyth County, VA, Wythe County, VA

The radar

The Roanoke radar (KFCX), 33 km from the middle of the area, began a volume at 19:34 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.6 hours before the alert went out and 305 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 2017-12-08Temperature 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 2017-12-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.1939587897117136156175Sfc1 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
1723 m above ground
0-6 km bulk shear
96 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
179 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

Everything else NWS Blacksburg, VA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 8, 4:15 AM ESTWinter Weather AdvisoryRNKAppomattox, Buckingham, Campbell, Carroll, Charlotte, Floyd and 10 more10 hr
Dec 8, 2:34 PM ESTWinter Storm WarningRNKAmherst, Appomattox, Bedford, Buckingham, Campbell, Carroll and 12 more25 hr

Nearby

Winter Weather Advisories in Virginia, 2017Every winter weather advisory in 2017

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.