Alert archive / Virginia / Frost Advisories in 2018

Frost Advisory 6, NWS Blacksburg, VA

October 18, 201822 counties in Virginia; 4 counties in West Virginia

NWS Blacksburg, VA issued this frost advisory at Oct 18, 2018, 3:50 PM EDT for 22 counties in Virginia; 4 counties in West Virginia. It took effect at Oct 19, 2018, 1:00 AM EDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued: Oct 18, 2018, 3:50 PM EDT (19:50 UTC)
In effect from: Oct 19, 2018, 1:00 AM EDT
Expired: Oct 19, 2018, 9:00 AM EDT
In force: 8 hr
Issued by: NWS Blacksburg, VA

All 26 counties

Alleghany County, VA, Amherst County, VA, Appomattox County, VA, Bath County, VA, Bland County, VA, Buckingham County, VA, Campbell County, VA, Charlotte County, VA, City of Buena Vista, VA, City of Covington, VA, City of Lexington, VA, City of Lynchburg, VA, City of Radford, VA, Craig County, VA, Giles County, VA, Grayson County, VA, Montgomery County, VA, Pulaski County, VA, Rockbridge County, VA, Smyth County, VA, Tazewell County, VA, Wythe County, VA, Greenbrier County, WV, Mercer County, WV, Monroe County, WV, Summers County, WV

The radar

The Roanoke radar (KFCX), 44 km from the middle of the area, began a volume at 19:50 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 12:00Z, 7.8 hours before the alert went out and 61 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: 1158 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 30 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 frost 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 frost advisory went out at Oct 17, 7:23 PM EDT, 20 hours 27 minutes earlier.

Area forecast discussion, Oct 17, 7:23 PM EDT, 20 hours 27 minutes before

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Nearby

Frost Advisories in Virginia, 2018 Frost Advisories in West Virginia, 2018 Every frost advisory in 2018

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.