Alert archive / Virginia / Dense Fog Advisories in 2021

Dense Fog Advisory 3, NWS Blacksburg, VA

January 16, 20214 counties in Virginia; Caswell County, North Carolina

NWS Blacksburg, VA issued this dense fog advisory at Jan 16, 2021, 1:09 AM EST for 4 counties in Virginia; Caswell County, North Carolina. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Jan 16, 2021, 1:09 AM EST (06:09 UTC)
Expired
Jan 16, 2021, 9:00 AM EST
In force
8 hr
Issued by
NWS Blacksburg, VA

Counties Caswell County, NC, Appomattox County, VA, Buckingham County, VA, Charlotte County, VA, Halifax County, VA

The radar

The Roanoke radar (KFCX), 126 km from the middle of the area, began a volume at 06:10 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

Roanoke, VA (KRNK), launched 00:00Z, 6.2 hours before the alert went out and 60 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, Roanoke, VA at 00:00Z on 2021-01-16Temperature 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, Roanoke, VA at 00:00Z on 2021-01-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -107 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
914 m above ground
0-6 km bulk shear
95 kt
0-1 km storm-relative helicity
-107 m²/s²
0-3 km storm-relative helicity
-51 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
Jan 16, 1:09 AM ESTFreezing Fog AdvisoryRNKAlleghany, Amherst, Bedford, Botetourt, Campbell, Carroll and 21 more8 hr
Jan 16, 3:26 PM ESTSpecial Weather StatementRNKBland, Giles, Montgomery, Pulaski, City of Radford34 min

Nearby

Dense Fog Advisories in Virginia, 2021Dense Fog Advisories in North Carolina, 2021Every dense fog advisory in 2021

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.