Alert archive / Virginia / Flash Flood Watches in 2018

Flash Flood Watch 8, NWS Blacksburg, VA

August 1, 201837 counties in Virginia; 9 counties in North Carolina; 4 counties in West Virginia

NWS Blacksburg, VA issued this flash flood watch at Aug 1, 2018, 3:44 AM EDT for 37 counties in Virginia; 9 counties in North Carolina; 4 counties in West Virginia. It took effect at Aug 1, 2018, 12:00 PM EDT. It was in force for 56 hr.

The area

The counties it named.

The facts

Issued: Aug 1, 2018, 3:44 AM EDT (07:44 UTC)
In effect from: Aug 1, 2018, 12:00 PM EDT
Expired: Aug 3, 2018, 8:00 PM EDT
In force: 56 hr
Issued by: NWS Blacksburg, VA
Flood severity: None

All 50 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, Alleghany County, VA, Amherst County, VA, Appomattox County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Buckingham County, VA, Campbell County, VA, Carroll County, VA, Charlotte County, VA, City of Buena Vista, VA, City of Covington, 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, Craig County, VA, Floyd County, VA, Franklin County, VA, Giles 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, 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), 11 km from the middle of the area, began a volume at 07:45 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 7.7 hours before the alert went out and 320 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: 704 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 777 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.6

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash 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 flash flood watch went out at Aug 1, 1:45 AM EDT, 1 hour 59 minutes earlier.

Area forecast discussion, Aug 1, 1:45 AM EDT, 1 hour 59 minutes before

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Hazardous weather outlook, Aug 1, 12:35 AM EDT, 3 hours 9 minutes before

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In the hours before

Special weather statement, Jul 31, 10:03 PM EDT, 5 hours 41 minutes before

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Special weather statement, Jul 31, 11:29 PM EDT, 4 hours 15 minutes before

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Special weather statement, Aug 1, 12:11 AM EDT, 3 hours 33 minutes before

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Special weather statement, Aug 1, 12:50 AM EDT, 2 hours 54 minutes before

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Special weather statement, Aug 1, 3:08 AM EDT, 36 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
Jul 31, 9:08 PM EDT	Areal Flood Advisory	RNK	Appomattox, Buckingham	3 hr
Jul 31, 9:31 PM EDT	Areal Flood Advisory	RNK	Henry, Pittsylvania, City of Martinsville	3 hr
Jul 31, 9:40 PM EDT	Special Weather Statement	RNK	Amherst, City of Lynchburg	50 min
Jul 31, 10:03 PM EDT	Special Weather Statement	RNK	City of Martinsville	57 min
Jul 31, 11:20 PM EDT	Areal Flood Advisory	RNK	Amherst, Appomattox, Campbell, Halifax, Pittsylvania, City of Danville and 1 more	115 min
Jul 31, 11:29 PM EDT	Special Weather Statement	RNK	Charlotte, Halifax	61 min
Aug 1, 12:11 AM EDT	Special Weather Statement	RNK	Appomattox, Buckingham	64 min
Aug 1, 12:50 AM EDT	Special Weather Statement	RNK	Buckingham	55 min
Aug 1, 3:57 PM EDT	Special Weather Statement	RNK	Bath	63 min
Aug 1, 4:50 PM EDT	Areal Flood Advisory	RNK	Carroll, Patrick	3 hr
Aug 1, 4:58 PM EDT	Special Weather Statement	RNK	Henry, Patrick	62 min
Aug 1, 5:10 PM EDT	Severe Thunderstorm Warning	RNK	Henry, Patrick	50 min
Aug 1, 5:26 PM EDT	Areal Flood Advisory	RNK	Franklin, Henry, Patrick, City of Martinsville	3 hr
Aug 1, 5:57 PM EDT	Severe Thunderstorm Warning	RNK	Franklin, Henry, Patrick, City of Martinsville	63 min
Aug 1, 6:35 PM EDT	Special Weather Statement	RNK	Pittsylvania, City of Danville	55 min
Aug 1, 6:58 PM EDT	Areal Flood Advisory	RNK	Franklin, Henry, Pittsylvania, City of Danville	2 hr
Aug 1, 7:04 PM EDT	Severe Thunderstorm Warning	RNK	Bedford, Campbell, Halifax, Pittsylvania	41 min
Aug 1, 7:19 PM EDT	Special Weather Statement	RNK	City of Danville	26 min
Aug 1, 7:45 PM EDT	Severe Thunderstorm Warning	RNK	Appomattox, Campbell, Charlotte, Halifax, Pittsylvania	45 min
Aug 1, 7:50 PM EDT	Flash Flood Warning	RNK	Henry, Pittsylvania, City of Danville, City of Martinsville	6 hr
Aug 1, 7:53 PM EDT	Special Weather Statement	RNK	City of Danville	67 min
Jul 31, 8:29 PM EDT	Areal Flood Warning	RNK	Wilkes, Yadkin	2 hr
Jul 31, 9:00 PM EDT	Special Weather Statement	RNK	Rockingham	45 min
Jul 31, 9:57 PM EDT	Areal Flood Warning	RNK	Yadkin	2 hr
Aug 1, 4:15 PM EDT	Special Weather Statement	RNK	Surry, Yadkin	45 min
Aug 1, 7:38 PM EDT	Flash Flood Warning	RNK	Stokes, Surry, Yadkin	6 hr

Nearby

Flash Flood Watches in Virginia, 2018 Flash Flood Watches in North Carolina, 2018 Flash Flood Watches in West Virginia, 2018 Every flash 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.