Alert archive / Tennessee / Mesoscale Discussions in 2009

Mesoscale Discussion 764

May 8, 2009Greene County, Mississippi County, Arkansas; 38 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at May 8, 2009, 3:24 PM CDT for Greene County, Mississippi County, Arkansas; 38 counties in Tennessee. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
May 8, 2009, 3:24 PM CDT (20:24 UTC)
Expired
May 8, 2009, 4:30 PM CDT
In force
66 min
Issued by
the Storm Prediction Center
All 40 counties

Greene County, AR, Mississippi County, AR, Bedford County, TN, Benton County, TN, Bledsoe County, TN, Cannon County, TN, Carroll County, TN, Cheatham County, TN, Chester County, TN, Coffee County, TN, Crockett County, TN, Cumberland County, TN, Davidson County, TN, Decatur County, TN, DeKalb County, TN, Dickson County, TN, Dyer County, TN, Fentress County, TN, Gibson County, TN, Haywood County, TN, Henderson County, TN, Hickman County, TN, Humphreys County, TN, Jackson County, TN, Lauderdale County, TN, Lewis County, TN, Madison County, TN, Marshall County, TN, Maury County, TN, Overton County, TN, Perry County, TN, Putnam County, TN, Rutherford County, TN, Smith County, TN, Tipton County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Williamson County, TN, Wilson County, TN

The radar

The Paducah radar (KPAH), 136 km from the middle of the area, began a volume at 20:23 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 8.4 hours before the alert went out and 166 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, Nashville Metro, TN at 12:00Z on 2009-05-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 117 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, Nashville Metro, TN at 12:00Z on 2009-05-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 88 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
117 J/kg
Mixed-layer CIN
-90 J/kg
Mixed-layer LCL
739 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
88 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

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
May 8, 4:31 AM CDTMesoscale DiscussionSPCBenton, Boone, Carroll, Crawford, Franklin, Johnson and 3 more59 min
May 8, 4:55 AM CDTSevere Thunderstorm Watch PDSSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 10 more7 hr
May 8, 7:17 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Fulton, Izard and 1 more58 min
May 8, 8:37 AM CDTMesoscale DiscussionSPCClay, Craighead, Crittenden, Cross, Faulkner, Greene and 12 more53 min
May 8, 9:21 AM CDTTornado WatchSPCClay, Cleburne, Craighead, Greene, Independence, Izard and 10 more7 hr
May 8, 11:08 AM CDTMesoscale DiscussionSPCBaxter, Boone, Carroll, Crawford, Franklin, Fulton and 6 more67 min
May 8, 2:16 PM CDTMesoscale DiscussionSPCClay, Craighead, Greene, Lawrence, Mississippi, Poinsett and 2 more89 min
May 8, 3:42 PM CDTTornado WatchSPCClay, Craighead, Greene, Mississippi, Poinsett7 hr
May 8, 5:52 PM CDTTornado WatchSPCBaxter, Benton, Boone, Carroll, Cleburne, Conway and 35 more11 hr
May 8, 4:29 AM CDTSevere Thunderstorm WatchSPCBedford, Benton, Cannon, Cheatham, Clay, Coffee and 30 more3 hr
May 8, 12:08 PM CDTMesoscale DiscussionSPCAnderson, Bledsoe, Campbell, Cannon, Clay, Coffee and 23 more97 min
May 8, 12:44 PM CDTSevere Thunderstorm WatchSPCAnderson, Bedford, Bledsoe, Blount, Campbell, Cannon and 31 more6 hr
May 8, 5:03 PM CDTMesoscale DiscussionSPCAnderson, Blount, Campbell, Carter, Claiborne, Cocke and 19 more87 min
May 8, 5:32 PM CDTTornado WatchSPCCarter, Cocke, Greene, Hawkins, Johnson, Sullivan and 2 more7 hr

Nearby

Mesoscale Discussions in Tennessee, 2009Mesoscale Discussions in Arkansas, 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.