Alert archive / Tennessee / Mesoscale Discussions in 2009

Mesoscale Discussion 178

February 28, 20095 states

The Storm Prediction Center issued this mesoscale discussion at Feb 28, 2009, 3:57 PM CST for 5 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Feb 28, 2009, 3:57 PM CST (21:57 UTC)
Expired
Feb 28, 2009, 8:00 PM CST
In force
4 hr
Issued by
the Storm Prediction Center
All 41 counties

Colbert County, AL, Lauderdale County, AL, Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Mississippi County, AR, Poinsett County, AR, Dunklin County, MO, Pemiscot County, MO, Alcorn County, MS, Benton County, MS, DeSoto County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Pontotoc County, MS, Prentiss County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Shelby County, TN, Tipton County, TN, Wayne County, TN

The radar

The Memphis radar (KNQA), 69 km from the middle of the area, began a volume at 21:57 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

Birmingham, AL (KBMX), launched 12:00Z, 10.0 hours before the alert went out and 321 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, Birmingham, AL at 12:00Z on 2009-02-28Temperature 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, Birmingham, AL at 12:00Z on 2009-02-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 368 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
449 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
368 m²/s²
0-3 km storm-relative helicity
414 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

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
Feb 27, 6:38 PM CSTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Butler, Chambers and 30 more97 min
Feb 27, 7:45 PM CSTTornado WatchSPCAutauga, Barbour, Bibb, Bullock, Butler, Chambers and 28 more7 hr
Feb 27, 8:48 PM CSTMesoscale DiscussionSPCColbert, Cullman, Franklin, Lamar, Lauderdale, Lawrence and 4 more117 min
Feb 27, 10:47 PM CSTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Chambers, Chilton and 23 more118 min
Feb 28, 2:15 AM CSTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Chambers, Chilton and 25 more90 min
Feb 28, 2:52 AM CSTTornado WatchSPCAutauga, Barbour, Bibb, Bullock, Chambers, Chilton and 15 more9 hr
Feb 28, 5:40 AM CSTMesoscale DiscussionSPCAutauga, Bullock, Butler, Chilton, Choctaw, Clarke and 17 more2 hr
Feb 28, 9:49 AM CSTMesoscale DiscussionSPCBaldwin, Barbour, Bullock, Coffee, Conecuh, Covington and 8 more86 min
Feb 28, 10:39 AM CSTTornado WatchSPCCoffee, Covington, Dale, Geneva, Henry, Houston7 hr
Feb 28, 5:43 PM CSTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston8 hr
Feb 28, 11:47 AM CSTMesoscale DiscussionSPCClay, Craighead, Fulton, Greene, Lawrence, Mississippi and 3 more4 hr
Feb 27, 6:22 PM CSTMesoscale DiscussionSPCAndrew, Atchison, Buchanan, Caldwell, Clay, Clinton and 8 more4 hr

Nearby

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