Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 131

February 18, 200933 counties in Alabama; 12 counties in Georgia; 15 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 18, 2009, 7:14 PM CST for 33 counties in Alabama; 12 counties in Georgia; 15 counties in Mississippi. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued
Feb 18, 2009, 7:14 PM CST (01:14 UTC)
Expired
Feb 18, 2009, 8:15 PM CST
In force
61 min
Issued by
the Storm Prediction Center
All 60 counties

Autauga County, AL, Bibb County, AL, Bullock County, AL, Butler County, AL, Calhoun County, AL, Chambers County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Cleburne County, AL, Conecuh County, AL, Coosa County, AL, Crenshaw County, AL, Dallas County, AL, Elmore County, AL, Greene County, AL, Hale County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Washington County, AL, Wilcox County, AL, Carroll County, GA, Coweta County, GA, Douglas County, GA, Fayette County, GA, Haralson County, GA, Harris County, GA, Heard County, GA, Meriwether County, GA, Muscogee County, GA, Paulding County, GA, Polk County, GA, Troup County, GA, Clarke County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Jasper County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Newton County, MS, Perry County, MS, Smith County, MS, Stone County, MS, Wayne County, MS

The radar

The Birmingham radar (KBMX), 84 km from the middle of the area, began a volume at 01:15 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

Birmingham, AL (KBMX), launched 00:00Z, 1.2 hours before the alert went out and 85 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 00:00Z on 2009-02-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 357 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, Birmingham, AL at 00:00Z on 2009-02-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 181 square meters per square second.1939587897117Sfc1 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
357 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
1137 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
181 m²/s²
0-3 km storm-relative helicity
168 m²/s²
Significant tornado parameter
0.4
Supercell composite
3.4

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 18, 7:42 PM CSTSevere Thunderstorm WatchSPCAutauga, Baldwin, Barbour, Bibb, Bullock, Butler and 31 more5 hr
Feb 18, 7:58 PM CSTMesoscale DiscussionSPCBarbour, Henry, Lee, Russell92 min
Feb 18, 9:14 PM CSTSevere Thunderstorm WatchSPCCoffee, Dale, Geneva, Henry, Houston6 hr
Feb 18, 10:55 PM CSTMesoscale DiscussionSPCBarbour, Bullock, Butler, Coffee, Conecuh, Covington and 10 more95 min
Feb 18, 7:02 PM CSTSevere Thunderstorm WatchSPCBryan, Bulloch, Candler, Chatham, Effingham, Evans and 6 more7 hr
Feb 18, 11:38 PM CSTSevere Thunderstorm WatchSPCAppling, Atkinson, Bacon, Brantley, Camden, Charlton and 8 more81 min
Feb 19, 12:41 AM CSTMesoscale DiscussionSPCBrantley, Brooks, Camden, Charlton, Clinch, Colquitt and 9 more49 min
Feb 19, 12:58 AM CSTTornado WatchSPCAppling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 31 more7 hr
Feb 19, 1:20 AM CSTMesoscale DiscussionSPCBryan, Bulloch, Candler, Chatham, Crisp, Dodge and 13 more25 min
Feb 19, 1:44 AM CSTTornado WatchSPCBryan, Chatham, Evans, Liberty, Long, McIntosh and 1 more3 hr
Feb 19, 3:19 AM CSTMesoscale DiscussionSPCAtkinson, Bacon, Brantley, Brooks, Bryan, Camden and 15 more56 min

Nearby

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