Alert archive / Virginia / Flash Flood Watches in 2018

Flash Flood Watch 6, NWS Blacksburg, VA

July 23, 201829 counties in Virginia; 9 counties in North Carolina

NWS Blacksburg, VA issued this flash flood watch at Jul 23, 2018, 2:45 PM EDT for 29 counties in Virginia; 9 counties in North Carolina. It was in force for 14 hr.

The area

The counties it named.

The facts

Issued: Jul 23, 2018, 2:45 PM EDT (18:45 UTC)
Expired: Jul 24, 2018, 5:00 AM EDT
In force: 14 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 18:48 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, 6.8 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: 295 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 561 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

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 Jul 23, 9:31 AM EDT, 5 hours 14 minutes earlier.

Area forecast discussion, Jul 23, 9:31 AM EDT, 5 hours 14 minutes before

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Hazardous weather outlook, Jul 23, 6:36 AM EDT, 8 hours 9 minutes before

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In the hours before

Local storm report, Jul 23, 9:45 AM EDT, 5 hours before

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Special weather statement, Jul 23, 1:30 PM EDT, 1 hour 15 minutes before

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Special weather statement, Jul 23, 2:31 PM EDT, 14 minutes before

Special Weather Statement
National Weather Service BLACKSBURG VA
231 PM EDT MON JUL 23 2018

VAZ011-013-014-231930-
Giles-Pulaski-Montgomery-
231 PM EDT MON JUL 23 2018

...A STRONG THUNDERSTORM WILL AFFECT
NORTHEASTERN PULASKI...SOUTHEASTERN GILES AND NORTHWESTERN MONTGOMERY
COUNTIES...

Until 330 PM EDT

At 229 PM EDT, a strong thunderstorm was located over Mc Coy. the
storm is nearly stationary.

Heavy rain, at a rate of an 1 to 2 inches per hour, is occurring
with this storm, and may cause localized flooding. Exercise caution
if driving along Dry Branch Road and Belspring road this afternoon.
Do not drive your vehicle through flooded roadways.

Locations impacted include...
Pembroke...
Mountain Lake...
Parrott...
Eggleston...
and Mc Coy.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 3720 8054 3717 8069 3734 8070 3736 8053
TIME...MOT...LOC 1829Z 191DEG 4KT 3725 8061

RS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 22, 8:31 PM EDT	Special Weather Statement	RNK	Halifax	29 min
Jul 22, 8:47 PM EDT	Severe Thunderstorm Warning	RNK	Halifax	42 min
Jul 22, 9:08 PM EDT	Severe Thunderstorm Warning	RNK	Franklin, Henry, Patrick, Pittsylvania, City of Danville, City of Martinsville	67 min
Jul 22, 9:53 PM EDT	Special Weather Statement	RNK	Bedford	37 min
Jul 22, 10:16 PM EDT	Special Weather Statement	RNK	Pittsylvania, City of Danville	44 min
Jul 22, 10:56 PM EDT	Special Weather Statement	RNK	Appomattox, Campbell	49 min
Jul 22, 10:59 PM EDT	Special Weather Statement	RNK	Roanoke, City of Roanoke, City of Salem	46 min
Jul 22, 11:05 PM EDT	Special Weather Statement	RNK	Halifax	25 min
Jul 22, 11:12 PM EDT	Special Weather Statement	RNK	Charlotte	18 min
Jul 22, 11:14 PM EDT	Special Weather Statement	RNK	Buckingham	46 min
Jul 22, 11:38 PM EDT	Special Weather Statement	RNK	City of Lynchburg	37 min
Jul 22, 11:59 PM EDT	Special Weather Statement	RNK	Amherst	46 min
Jul 23, 12:03 AM EDT	Special Weather Statement	RNK	Buckingham	57 min
Jul 23, 12:12 AM EDT	Special Weather Statement	RNK	Amherst	33 min
Jul 23, 7:49 AM EDT	Special Weather Statement	RNK	Botetourt	41 min
Jul 23, 1:30 PM EDT	Special Weather Statement	RNK	Giles	45 min
Jul 23, 2:31 PM EDT	Special Weather Statement	RNK	Giles	59 min
Jul 23, 5:28 PM EDT	Special Weather Statement	RNK	City of Danville	32 min
Jul 23, 5:57 PM EDT	Special Weather Statement	RNK	Pittsylvania	33 min
Jul 23, 6:26 PM EDT	Special Weather Statement	RNK	Pittsylvania	34 min
Jul 23, 6:29 PM EDT	Special Weather Statement	RNK	Halifax	31 min
Jul 22, 8:15 PM EDT	Severe Thunderstorm Warning	RNK	Caswell, Rockingham, Stokes	75 min
Jul 22, 9:45 PM EDT	Severe Thunderstorm Warning	RNK	Caswell	45 min
Jul 22, 10:31 PM EDT	Special Weather Statement	RNK	Caswell	29 min
Jul 23, 6:46 PM EDT	Special Weather Statement	RNK	Stokes, Surry, Wilkes, Yadkin	59 min
Jul 23, 7:41 PM EDT	Special Weather Statement	RNK	Alleghany	64 min

Nearby

Flash Flood Watches in Virginia, 2018 Flash Flood Watches in North Carolina, 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.