Alert archive / Virginia / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 452

July 1, 20124 states

The Storm Prediction Center issued this severe thunderstorm watch at Jul 1, 2012, 9:06 PM EDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jul 1, 2012, 9:06 PM EDT (01:06 UTC)
Expired
Jul 2, 2012, 2:00 AM EDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 91 counties

Breathitt County, KY, Estill County, KY, Floyd County, KY, Harlan County, KY, Knott County, KY, Lee County, KY, Leslie County, KY, Letcher County, KY, Owsley County, KY, Perry County, KY, Pike County, KY, Allegany County, MD, Garrett County, MD, Washington County, MD, Alleghany County, VA, Amherst County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Buchanan County, VA, Carroll County, VA, City of Buena Vista, VA, City of Covington, VA, City of Danville, VA, City of Galax, VA, City of Harrisonburg, 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, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Craig County, VA, Dickenson County, VA, Floyd County, VA, Franklin County, VA, Frederick County, VA, Giles County, VA, Grayson County, VA, Henry County, VA, Highland County, VA, Montgomery County, VA, Nelson County, VA, Page County, VA, Patrick County, VA, Pittsylvania County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Smyth County, VA, Tazewell County, VA, Warren County, VA, Wythe County, VA, Barbour County, WV, Berkeley County, WV, Braxton County, WV, Fayette County, WV, Grant County, WV, Greenbrier County, WV, Hampshire County, WV, Hardy County, WV, Harrison County, WV, Jefferson County, WV, Lewis County, WV, Marion County, WV, McDowell County, WV, Mercer County, WV, Mineral County, WV, Monongalia County, WV, Monroe County, WV, Morgan County, WV, Nicholas County, WV, Pendleton County, WV, Pocahontas County, WV, Preston County, WV, Raleigh County, WV, Randolph County, WV, Summers County, WV, Taylor County, WV, Tucker County, WV, Upshur County, WV, Webster County, WV, Wyoming County, WV

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
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 1, 9:11 PM EDTSevere Thunderstorm WarningJKLFloyd, Johnson, Magoffin, Martin, Pike49 min
Jul 1, 9:15 PM EDTSevere Thunderstorm WarningRLXBoone, Cabell, Fayette, Kanawha, Lincoln, Logan and 5 more60 min
Jul 1, 9:24 PM EDTSevere Thunderstorm WarningRLXBarbour, Braxton, Doddridge, Gilmer, Harrison, Lewis and 2 more41 min
Jul 1, 9:26 PM EDTSevere Thunderstorm WarningJKLBreathitt, Floyd, Knott, Lee, Magoffin, Morgan and 2 more49 min
Jul 1, 9:52 PM EDTSevere Thunderstorm WarningJKLFloyd, Pike23 min
Jul 1, 10:09 PM EDTSevere Thunderstorm WarningJKLEstill, Jackson, Lee, Owsley, Rockcastle51 min
Jul 1, 10:18 PM EDTSevere Thunderstorm WarningRLXBoone, Logan, McDowell, Mingo, Wyoming42 min
Jul 1, 10:27 PM EDTSevere Thunderstorm WarningRLXBuchanan, Dickenson33 min
Jul 1, 10:38 PM EDTSevere Thunderstorm WarningRNKGreenbrier52 min
Jul 1, 10:48 PM EDTSevere Thunderstorm WarningRLXBuchanan27 min
Jul 1, 10:50 PM EDTSevere Thunderstorm WarningJKLEstill, Powell, Wolfe25 min
Jul 1, 10:53 PM EDTSevere Thunderstorm WarningRNKBland, Tazewell67 min
Jul 1, 10:56 PM EDTSevere Thunderstorm WarningRLXMcDowell, Raleigh, Wyoming19 min
Jul 1, 11:04 PM EDTSevere Thunderstorm WarningRLXFayette, Raleigh26 min
Jul 1, 11:20 PM EDTSevere Thunderstorm WarningRNKBland, Carroll, Grayson, Pulaski, Smyth, Tazewell and 1 more55 min
Jul 1, 11:33 PM EDTSevere Thunderstorm WarningRNKGrayson, Smyth57 min
Jul 1, 11:44 PM EDTSevere Thunderstorm WarningRNKFloyd, Giles, Montgomery, Pulaski, City of Radford61 min
Jul 1, 11:57 PM EDTSevere Thunderstorm WarningRNKCarroll, Floyd, Grayson, Patrick, Pulaski, Wythe and 1 more63 min
Jul 2, 12:24 AM EDTSevere Thunderstorm WarningRNKFloyd, Franklin, Henry, Montgomery, Patrick, Pittsylvania and 2 more66 min
Jul 2, 12:58 AM EDTSevere Thunderstorm WarningRNKPatrick62 min
Jul 2, 1:12 AM EDTSevere Thunderstorm WarningRNKFranklin, Halifax, Henry, Patrick, Pittsylvania, City of Danville and 1 more93 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 00:00Z, 1.1 hours before the alert went out and 163 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-pSkew-T log-p diagram, Roanoke, VA at 00:00Z on 2012-07-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 102 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Roanoke, VA at 00:00Z on 2012-07-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
102 J/kg
Mixed-layer CIN
-174 J/kg
Mixed-layer LCL
2439 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 1, 8:21 PM EDTMesoscale DiscussionSPCBoyd, Carter, Greenup, Lawrence54 min
Jul 1, 8:32 PM EDTMesoscale DiscussionSPCFloyd, Knott, Leslie, Letcher, Magoffin, Perry and 1 more88 min
Jul 1, 9:02 PM EDTMesoscale DiscussionSPCAnderson, Boone, Bourbon, Boyle, Bracken, Breckinridge and 33 more58 min
Jul 1, 10:26 PM EDTMesoscale DiscussionSPCAdair, Anderson, Bath, Bourbon, Boyd, Boyle and 46 more94 min
Jul 2, 6:16 PM EDTMesoscale DiscussionSPCAdair, Allen, Ballard, Barren, Breckinridge, Bullitt and 40 more2 hr
Jul 2, 12:39 AM EDTMesoscale DiscussionSPCMontgomery96 min

Nearby

Severe Thunderstorm Watches in Virginia, 2012Severe Thunderstorm Watches in West Virginia, 2012Severe Thunderstorm Watches in Kentucky, 2012Every severe thunderstorm watch in 2012

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.