Alert archive / Virginia / Flash Flood Watches in 2020

Flash Flood Watch 4, NWS Blacksburg, VA

May 27, 202033 counties in Virginia; 8 counties in North Carolina; 4 counties in West Virginia

NWS Blacksburg, VA issued this flash flood watch at May 27, 2020, 3:25 AM EDT for 33 counties in Virginia; 8 counties in North Carolina; 4 counties in West Virginia. It took effect at May 27, 2020, 4:00 PM EDT. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued: May 27, 2020, 3:25 AM EDT (07:25 UTC)
In effect from: May 27, 2020, 4:00 PM EDT
Expired: May 28, 2020, 1:58 AM EDT
In force: 10 hr
Issued by: NWS Blacksburg, VA
Flood severity: None

All 45 counties

Alleghany County, NC, Ashe County, NC, Caswell County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Wilkes County, NC, Yadkin County, NC, Alleghany County, VA, Amherst County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Campbell County, VA, Carroll 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, 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), 7 km from the middle of the area, began a volume at 07:24 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, 7.4 hours before the alert went out and 117 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: 1209 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 23 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 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 May 27, 3:20 AM EDT, 5 minutes earlier.

Area forecast discussion, May 27, 3:20 AM EDT, 5 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
May 27, 5:39 PM EDT	Special Weather Statement	RNK	Pittsylvania	36 min
May 27, 6:15 PM EDT	Special Weather Statement	RNK	Pittsylvania	30 min

Nearby

Flash Flood Watches in Virginia, 2020 Flash Flood Watches in North Carolina, 2020 Flash Flood Watches in West Virginia, 2020 Every flash flood watch in 2020

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.