Alert archive / Tennessee / Mesoscale Discussions in 2009

Mesoscale Discussion 439

April 10, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Apr 10, 2009, 7:53 PM EDT for 4 states. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Apr 10, 2009, 7:53 PM EDT (23:53 UTC)
Expired
Apr 10, 2009, 9:00 PM EDT
In force
67 min
Issued by
the Storm Prediction Center
All 26 counties

Harlan County, KY, Letcher County, KY, Mitchell County, NC, Carter County, TN, Claiborne County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Jefferson County, TN, Johnson County, TN, Sullivan County, TN, Unicoi County, TN, Union County, TN, Washington County, TN, Buchanan County, VA, City of Bristol, VA, City of Norton, VA, Dickenson County, VA, Lee County, VA, Russell County, VA, Scott County, VA, Tazewell County, VA, Washington County, VA, Wise County, VA

The radar

The Knoxville radar (KMRX), 63 km from the middle of the area, began a volume at 23:55 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, 11.9 hours before the alert went out and 268 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 2009-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2009-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1528 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
127 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.

IssuedProductOfficeCountiesLasted
Apr 9, 11:52 PM EDTSevere Thunderstorm WatchSPCBallard, Calloway, Carlisle, Crittenden, Fulton, Graves and 5 more4 hr
Apr 10, 1:50 AM EDTMesoscale DiscussionSPCBallard, Breckinridge, Butler, Caldwell, Calloway, Carlisle and 26 more85 min
Apr 10, 2:22 AM EDTSevere Thunderstorm WatchSPCAllen, Barren, Breckinridge, Bullitt, Butler, Caldwell and 23 more4 hr
Apr 10, 4:33 AM EDTMesoscale DiscussionSPCAdair, Allen, Barren, Breckinridge, Bullitt, Butler and 28 more57 min
Apr 10, 9:22 AM EDTMesoscale DiscussionSPCCalloway, Marshall, Todd, Trigg83 min
Apr 10, 9:53 AM EDTTornado WatchSPCAdair, Allen, Anderson, Barren, Bourbon, Boyle and 64 more7 hr
Apr 10, 11:30 AM EDTMesoscale DiscussionSPCAnderson, Bourbon, Boyle, Breckinridge, Bullitt, Clark and 14 more60 min
Apr 10, 12:14 PM EDTMesoscale DiscussionSPCAllen, Calloway, Christian, Logan, Lyon, Marshall and 4 more76 min
Apr 10, 2:26 PM EDTMesoscale DiscussionSPCAdair, Allen, Anderson, Barren, Bath, Bell and 87 more64 min
Apr 10, 2:51 PM EDTTornado WatchSPCBath, Bell, Breathitt, Clay, Elliott, Estill and 27 more6 hr
Apr 10, 3:56 PM EDTMesoscale DiscussionSPCBreathitt, Clark, Elliott, Estill, Floyd, Jackson and 12 more64 min
Apr 10, 4:06 PM EDTMesoscale DiscussionSPCAdair, Allen, Barren, Breckinridge, Bullitt, Edmonson and 15 more54 min
Apr 10, 4:42 PM EDTMesoscale DiscussionSPCBreathitt, Clay, Elliott, Floyd, Harlan, Johnson and 14 more63 min
Apr 10, 8:04 AM EDTMesoscale DiscussionSPCClay86 min
Apr 10, 12:23 PM EDTTornado Watch PDSSPCCherokee, Clay8 hr
Apr 10, 3:39 PM EDTTornado Watch PDSSPCGraham, Haywood, Jackson, Macon, Swain8 hr
Apr 9, 11:48 PM EDTTornado WatchSPCCrockett, Dyer, Fayette, Gibson, Haywood, Lake and 4 more4 hr
Apr 10, 2:24 AM EDTMesoscale DiscussionSPCHardeman, Hardin, McNairy96 min
Apr 10, 1:58 PM EDTMesoscale DiscussionSPCBedford, Cannon, Coffee, DeKalb, Franklin, Giles and 17 more92 min
Apr 10, 4:43 PM EDTMesoscale DiscussionSPCPolk92 min

Nearby

Mesoscale Discussions in Tennessee, 2009Mesoscale Discussions in Virginia, 2009Mesoscale Discussions in Kentucky, 2009Every mesoscale discussion 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.