Alert archive / Virginia / Severe Thunderstorm Watches in 2013

Severe Thunderstorm Watch 22

January 30, 20139 counties in North Carolina; 31 counties in Virginia

The Storm Prediction Center issued this severe thunderstorm watch at Jan 30, 2013, 3:42 PM EST for 9 counties in North Carolina; 31 counties in Virginia. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jan 30, 2013, 3:42 PM EST (20:42 UTC)
Expired: Jan 30, 2013, 8:22 PM EST
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 65 kt

All 40 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, 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, Wythe County, VA

The radar

The Roanoke radar (KFCX), 29 km from the middle of the area, began a volume at 20:41 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 20%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 50%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 5%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jan 30, 4:02 PM EST	Severe Thunderstorm Warning	RNK	Alleghany, Bedford, Botetourt, Craig, Franklin, Giles and 4 more	58 min
Jan 30, 4:19 PM EST	Flash Flood Warning Emergency	RNK	Alleghany, Ashe, Watauga	10 hr
Jan 30, 4:52 PM EST	Severe Thunderstorm Warning	RNK	Alleghany, Amherst, Bedford, Botetourt, Roanoke, Rockbridge and 4 more	53 min
Jan 30, 5:48 PM EST	Severe Thunderstorm Warning	RNK	Amherst, Appomattox, City of Lynchburg	42 min
Jan 30, 6:25 PM EST	Flash Flood Warning	RNK	Alleghany, Ashe, Stokes, Surry, Watauga, Wilkes	6 hr
Jan 30, 6:39 PM EST	Flash Flood Warning	RNK	Alleghany, Amherst, Bath, Bedford, Botetourt, Craig and 8 more	6 hr
Jan 30, 7:59 PM EST	Flash Flood Warning	RNK	Rockingham, Stokes, Surry, Wilkes, Yadkin	6 hr
Jan 30, 8:02 PM EST	Flash Flood Warning	RNK	Amherst, Appomattox, Bedford, Campbell, Franklin, Henry and 4 more	6 hr
Jan 30, 8:22 PM EST	Severe Thunderstorm Warning	RNK	Rockingham, Stokes	53 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 8.7 hours before the alert went out and 43 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: 5 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 561 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 299 m²/s²
0-3 km storm-relative helicity: 488 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 30, 5:51 AM EST	Tornado Watch	SPC	Cherokee, Clay	7 hr
Jan 30, 7:38 AM EST	Mesoscale Discussion	SPC	Swain	97 min
Jan 30, 8:11 AM EST	Tornado Watch	SPC	Graham, Jackson, Macon, Swain	7 hr
Jan 30, 12:50 PM EST	Mesoscale Discussion	SPC	Alexander, Avery, Buncombe, Burke, Caldwell, Catawba and 21 more	85 min
Jan 30, 1:19 PM EST	Tornado Watch	SPC	Alexander, Avery, Buncombe, Burke, Cabarrus, Caldwell and 22 more	9 hr
Jan 30, 3:21 PM EST	Mesoscale Discussion	SPC	Alleghany, Rockingham, Stokes, Surry, Wilkes, Yadkin	84 min
Jan 30, 4:06 PM EST	Mesoscale Discussion	SPC	Alamance, Chatham, Davidson, Durham, Franklin, Granville and 6 more	114 min
Jan 30, 4:13 PM EST	Mesoscale Discussion	SPC	Gaston, Mecklenburg	2 hr
Jan 30, 8:31 AM EST	Severe Thunderstorm Watch	SPC	Bland, Carroll, Giles, Grayson, Pulaski, Smyth and 4 more	4 hr
Jan 30, 10:19 AM EST	Mesoscale Discussion	SPC	Albemarle, Alleghany, Amherst, Augusta, Bath, Bedford and 43 more	86 min
Jan 30, 12:54 PM EST	Mesoscale Discussion	SPC	Albemarle, Alleghany, Amelia, Amherst, Appomattox, Arlington and 74 more	96 min
Jan 30, 6:31 PM EST	Tornado Watch	SPC	Albemarle, Arlington, Caroline, Culpeper, Fairfax, Fauquier and 17 more	8 hr

Nearby

Severe Thunderstorm Watches in Virginia, 2013 Severe Thunderstorm Watches in North Carolina, 2013 Every severe thunderstorm watch in 2013

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.