Alert archive / North Carolina / Tornado Watches in 2009

Tornado Watch 273

May 8, 20095 states

The Storm Prediction Center issued this tornado watch at May 8, 2009, 6:32 PM EDT for 5 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
May 8, 2009, 6:32 PM EDT (22:32 UTC)
Expired
May 9, 2009, 2:00 AM EDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
50 kt
All 61 counties

Franklin County, GA, Habersham County, GA, Hart County, GA, Rabun County, GA, Stephens County, GA, Alexander County, NC, Alleghany County, NC, Ashe County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Catawba County, NC, Cleveland County, NC, Graham County, NC, Haywood County, NC, Henderson County, NC, Jackson County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Surry County, NC, Swain County, NC, Transylvania County, NC, Watauga County, NC, Wilkes County, NC, Yancey County, NC, Abbeville County, SC, Anderson County, SC, Cherokee County, SC, Greenville County, SC, Laurens County, SC, Oconee County, SC, Pickens County, SC, Spartanburg County, SC, Union County, SC, Carter County, TN, Cocke County, TN, Greene County, TN, Hawkins County, TN, Johnson County, TN, Sullivan County, TN, Unicoi County, TN, Washington County, TN, Bland County, VA, Carroll County, VA, City of Bristol, VA, City of Galax, VA, City of Radford, VA, Giles County, VA, Grayson County, VA, Pulaski County, VA, Russell County, VA, Scott County, VA, Smyth County, VA, Tazewell County, VA, Washington County, VA, Wythe County, VA

The radar

The Knoxville radar (KMRX), 129 km from the middle of the area, began a volume at 22:32 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
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 8, 6:50 PM EDTSevere Thunderstorm WarningGSPJackson, Swain39 min
May 8, 7:21 PM EDTSevere Thunderstorm WarningGSPHaywood, Jackson39 min
May 8, 7:26 PM EDTTornado WarningMRXClaiborne, Grainger, Greene, Hamblen, Hancock, Hawkins64 min
May 8, 7:47 PM EDTSevere Thunderstorm WarningRNKAlleghany, Ashe24 min
May 8, 8:09 PM EDTTornado WarningMRXGreene, Hawkins, Sullivan, Washington51 min
May 8, 8:49 PM EDTTornado WarningMRXCarter, Johnson, Sullivan, Washington43 min
May 8, 9:18 PM EDTTornado WarningMRXRussell27 min
May 8, 9:22 PM EDTTornado WarningMRXRussell, Scott, Wise, City of Norton53 min
May 8, 9:26 PM EDTTornado WarningRNKBland, Smyth, Tazewell, Wythe51 min
May 8, 9:31 PM EDTFlash Flood WarningRNKBland, Giles, Tazewell6 hr
May 8, 9:34 PM EDTTornado WarningRNKBland, Tazewell41 min
May 8, 10:08 PM EDTTornado WarningMRXRussell, Washington52 min
May 8, 10:39 PM EDTTornado WarningRNKSmyth, Tazewell, Wythe41 min
May 8, 11:05 PM EDTTornado WarningRNKGrayson, Smyth, Wythe40 min
May 8, 11:41 PM EDTSevere Thunderstorm WarningRNKAlleghany, Surry64 min
May 9, 12:46 AM EDTFlash Flood WarningRNKBland, Grayson, Smyth, Tazewell, Wythe4 hr

Discussions around it

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

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 10.5 hours before the alert went out and 187 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, Greensboro/Hi Pt, NC at 12:00Z on 2009-05-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 44 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, Greensboro/Hi Pt, NC at 12:00Z on 2009-05-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.19395878Sfc1 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
44 J/kg
Mixed-layer CIN
-125 J/kg
Mixed-layer LCL
1315 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
138 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
May 8, 11:35 AM EDTMesoscale DiscussionSPCColumbia, Elbert, Lincoln, Wilkes85 min
May 8, 6:03 PM EDTMesoscale DiscussionSPCRabun, Towns, Union87 min
May 7, 10:18 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Chowan, Cumberland, Duplin and 19 more87 min
May 8, 2:02 PM EDTSevere Thunderstorm WatchSPCAnson, Bladen, Brunswick, Carteret, Columbus, Craven and 17 more4 hr
May 8, 5:29 AM EDTSevere Thunderstorm WatchSPCBedford, Benton, Cannon, Cheatham, Clay, Coffee and 30 more3 hr
May 8, 9:37 AM EDTMesoscale DiscussionSPCBedford, Benton, Cannon, Carroll, Cheatham, Chester and 46 more53 min
May 8, 10:21 AM EDTTornado WatchSPCBenton, Carroll, Cheatham, Chester, Crockett, Davidson and 27 more7 hr
May 8, 1:08 PM EDTMesoscale DiscussionSPCAnderson, Bledsoe, Campbell, Cannon, Clay, Coffee and 23 more97 min
May 8, 1:44 PM EDTSevere Thunderstorm WatchSPCAnderson, Bedford, Bledsoe, Blount, Campbell, Cannon and 31 more6 hr
May 8, 3:16 PM EDTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Crockett, Decatur, Dickson and 17 more89 min
May 8, 4:24 PM EDTMesoscale DiscussionSPCBedford, Benton, Bledsoe, Cannon, Carroll, Cheatham and 32 more66 min
May 8, 4:42 PM EDTTornado WatchSPCAnderson, Bedford, Benton, Bledsoe, Blount, Campbell and 66 more7 hr

Nearby

Tornado Watches in North Carolina, 2009Tornado Watches in Virginia, 2009Tornado Watches in South Carolina, 2009Every tornado watch in 2009

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.