Alert archive / Virginia / Dense Fog Advisories in 2021

Dense Fog Advisory 4, NWS Blacksburg, VA

January 26, 202121 counties in Virginia; 6 counties in North Carolina

NWS Blacksburg, VA issued this dense fog advisory at Jan 26, 2021, 7:40 PM EST for 21 counties in Virginia; 6 counties in North Carolina. It was in force for 11 hr.

The area

The counties it named.

The facts

Issued: Jan 26, 2021, 7:40 PM EST (00:40 UTC)
Expired: Jan 27, 2021, 6:18 AM EST
In force: 11 hr
Issued by: NWS Blacksburg, VA

All 27 counties

Caswell County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Wilkes County, NC, Yadkin County, NC, Amherst County, VA, Appomattox County, VA, Bedford County, VA, Botetourt County, VA, Buckingham County, VA, Campbell County, VA, Charlotte County, VA, City of Buena Vista, VA, City of Danville, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Roanoke, VA, City of Salem, VA, Franklin County, VA, Halifax County, VA, Henry County, VA, Patrick County, VA, Pittsylvania County, VA, Roanoke County, VA, Rockbridge County, VA

The radar

The Roanoke radar (KFCX), 55 km from the middle of the area, began a volume at 00:45 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

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 0.7 hours before the alert went out and 106 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1846 m above ground
0-6 km bulk shear: 84 kt
0-1 km storm-relative helicity: 127 m²/s²
0-3 km storm-relative helicity: 132 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Blacksburg, VA wrote its last area forecast discussion before this dense fog advisory went out at Jan 26, 7:08 PM EST, 32 minutes earlier.

Area forecast discussion, Jan 26, 7:08 PM EST, 32 minutes before

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Hazardous weather outlook, Jan 26, 4:22 PM EST, 3 hours 18 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jan 27, 4:32 AM EST	Winter Storm Warning	RNK	Bland, Grayson, Tazewell	31 hr
Jan 27, 4:32 AM EST	Winter Weather Advisory	RNK	Bland, Carroll, Craig, Floyd, Franklin, Giles and 17 more	31 hr

Nearby

Dense Fog Advisories in Virginia, 2021 Dense Fog Advisories in North Carolina, 2021 Every 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.