Alert archive / Tennessee / Mesoscale Discussions in 2009

Mesoscale Discussion 430

April 10, 200914 counties in Alabama; Itawamba County, Mississippi; 23 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 10, 2009, 12:58 PM CDT for 14 counties in Alabama; Itawamba County, Mississippi; 23 counties in Tennessee. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Apr 10, 2009, 12:58 PM CDT (17:58 UTC)
Expired
Apr 10, 2009, 2:30 PM CDT
In force
92 min
Issued by
the Storm Prediction Center
All 38 counties

Colbert County, AL, Cullman County, AL, Fayette County, AL, Franklin County, AL, Jackson County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Morgan County, AL, Walker County, AL, Winston County, AL, Itawamba County, MS, Bedford County, TN, Cannon County, TN, Coffee County, TN, DeKalb County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Jackson County, TN, Lawrence County, TN, Lincoln County, TN, Marshall County, TN, Maury County, TN, Moore County, TN, Putnam County, TN, Rutherford County, TN, Smith County, TN, Sumner County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Williamson County, TN, Wilson County, TN

The radar

The Northeast Alabama radar (KHTX), 51 km from the middle of the area, began a volume at 18:00 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

Nashville Metro, TN (KBNA), launched 12:00Z, 6.0 hours before the alert went out and 107 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 2009-04-10Temperature 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, Nashville Metro, TN at 12:00Z on 2009-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -50 square meters per square second.1939587897Sfc1 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
1414 m above ground
0-6 km bulk shear
71 kt
0-1 km storm-relative helicity
-50 m²/s²
0-3 km storm-relative helicity
-4 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.

000 
ACUS11 KWNS 101759
SWOMCD
SPC MCD 101758 
TNZ000-ALZ000-MSZ000-101930-

MESOSCALE DISCUSSION 0430
NWS STORM PREDICTION CENTER NORMAN OK
1258 PM CDT FRI APR 10 2009

AREAS AFFECTED...NERN MS...NRN AL THROUGH MIDDLE TN

CONCERNING...TORNADO WATCH 132...

VALID 101758Z - 101930Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 132 CONTINUES.

THREAT FOR STRONG/DAMAGING TORNADOES WILL LIKELY PERSIST NEXT FEW
HOURS WITH STORMS MOVING THROUGH MIDDLE TN INTO NRN AL. LARGE HAIL
AND DAMAGING WIND MAY ALSO ACCOMPANY SOME OF THE STRONGER STORMS.

COUPLE OF LINES OF MOSTLY DISCRETE SUPERCELLS CONTINUE FROM MIDDLE
TN SWWD THROUGH EXTREME NERN MS INTO NW AL. THE ATMOSPHERE REMAINS
MODERATELY UNSTABLE WITH MINIMAL CONVECTIVE INHIBITION ALLOWING
STORMS TO CONTINUE DEVELOPING ALONG CLOUD STREETS IN WARM SECTOR
AHEAD OF THE EWD ADVANCING COLD FRONT. BULK SHEAR OF 50+ KT AND
LARGE HODOGRAPHS WITH 0-1 KM STORM RELATIVE HELICITY FROM 200-300
M2/S2 ASSOCIATED WITH THE EWD ADVANCING SHORTWAVE TROUGH WILL
CONTINUE TO PROMOTE SUPERCELLS WITH LOW LEVEL MESOCYCLONES. GIVEN
THE PROPENSITY TO MAINTAIN DISCRETE STORMS WITHIN THE FAVORABLY
SHEARED AND MODERATELY UNSTABLE ENVIRONMENT...SOME SUPERCELLS WILL
REMAIN CAPABLE OF PRODUCING STRONG TORNADOES NEXT FEW HOURS.

..DIAL.. 04/10/2009

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MRX...OHX...BMX...HUN...MEG...

LAT...LON   35588530 34408617 33568771 34038864 35298742 36538647
            36358553 35588530

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 10, 1:24 AM CDTMesoscale DiscussionSPCColbert, Fayette, Franklin, Lamar, Lauderdale, Marion and 1 more96 min
Apr 10, 1:43 AM CDTTornado WatchSPCBlount, Colbert, Cullman, Fayette, Franklin, Greene and 12 more5 hr
Apr 10, 4:25 AM CDTMesoscale DiscussionSPCBlount, Calhoun, Cherokee, Cleburne, Cullman, DeKalb and 13 more95 min
Apr 10, 8:22 AM CDTMesoscale DiscussionSPCLauderdale83 min
Apr 10, 11:14 AM CDTMesoscale DiscussionSPCColbert, Franklin, Jackson, Lauderdale, Lawrence, Limestone and 4 more76 min
Apr 10, 11:23 AM CDTTornado Watch PDSSPCBibb, Blount, Calhoun, Cherokee, Cleburne, Colbert and 25 more8 hr
Apr 10, 2:29 PM CDTMesoscale DiscussionSPCCleburne91 min
Apr 10, 2:39 PM CDTTornado Watch PDSSPCAutauga, Barbour, Bullock, Calhoun, Chambers, Cherokee and 19 more8 hr
Apr 10, 3:43 PM CDTMesoscale DiscussionSPCBlount, Calhoun, Cherokee, Cleburne, DeKalb, Etowah and 4 more92 min
Apr 10, 6:34 PM CDTMesoscale DiscussionSPCAutauga, Calhoun, Chambers, Chilton, Clay, Cleburne and 9 more56 min
Apr 9, 10:48 PM CDTTornado WatchSPCBolivar, Carroll, Coahoma, DeSoto, Grenada, Holmes and 17 more4 hr
Apr 10, 8:53 AM CDTTornado WatchSPCAlcorn, Benton, Calhoun, Chickasaw, DeSoto, Itawamba and 11 more7 hr
Apr 10, 12:50 AM CDTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Davidson, Decatur and 16 more85 min
Apr 10, 1:22 AM CDTSevere Thunderstorm WatchSPCBedford, Benton, Carroll, Cheatham, Chester, Davidson and 28 more4 hr
Apr 10, 3:33 AM CDTMesoscale DiscussionSPCBedford, Cannon, Cheatham, Clay, Coffee, Davidson and 24 more57 min
Apr 10, 1:51 PM CDTTornado WatchSPCCarter, Claiborne, Cocke, Grainger, Greene, Hamblen and 8 more6 hr
Apr 10, 3:42 PM CDTMesoscale DiscussionSPCCarter, Hancock, Hawkins, Johnson, Sullivan, Unicoi and 1 more63 min
Apr 10, 6:53 PM CDTMesoscale DiscussionSPCCarter, Claiborne, Grainger, Greene, Hamblen, Hancock and 7 more67 min

Nearby

Mesoscale Discussions in Tennessee, 2009Mesoscale Discussions in Alabama, 2009Mesoscale Discussions in Mississippi, 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.