Alert archive / Virginia / Flood Watches in 2018

Flood Watch 4, NWS Blacksburg, VA

December 13, 201829 counties in Virginia; 9 counties in North Carolina

NWS Blacksburg, VA issued this flood watch at Dec 13, 2018, 2:54 PM EST for 29 counties in Virginia; 9 counties in North Carolina. It took effect at Dec 14, 2018, 1:00 PM EST. It was in force for 26 hr.

The area

The counties it named.

The facts

Issued: Dec 13, 2018, 2:54 PM EST (19:54 UTC)
In effect from: Dec 14, 2018, 1:00 PM EST
Expired: Dec 15, 2018, 2:44 PM EST
In force: 26 hr
Issued by: NWS Blacksburg, VA
Flood severity: None

All 38 counties

Alleghany County, NC, Ashe County, NC, Caswell County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Watauga 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, Carroll County, VA, Charlotte County, VA, City of Buena Vista, VA, City of Danville, VA, City of Galax, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, Floyd County, VA, Franklin County, VA, Grayson County, VA, Halifax County, VA, Henry County, VA, Montgomery County, VA, Patrick County, VA, Pittsylvania County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Wythe County, VA

The radar

The Roanoke radar (KFCX), 24 km from the middle of the area, began a volume at 19:55 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 12:00Z, 7.9 hours before the alert went out and 96 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: 1859 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 140 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 flood watch 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 flood watch went out at Dec 13, 11:55 AM EST, 2 hours 59 minutes earlier.

Area forecast discussion, Dec 13, 11:55 AM EST, 2 hours 59 minutes before

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Hazardous weather outlook, Dec 13, 4:17 AM EST, 10 hours 37 minutes before

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Nearby

Flood Watches in Virginia, 2018 Flood Watches in North Carolina, 2018 Every flood watch 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.