Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 172

February 28, 200931 counties in Alabama; 4 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 28, 2009, 2:15 AM CST for 31 counties in Alabama; 4 counties in Mississippi. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
Feb 28, 2009, 2:15 AM CST (08:15 UTC)
Expired
Feb 28, 2009, 3:45 AM CST
In force
90 min
Issued by
the Storm Prediction Center
All 35 counties

Autauga County, AL, Barbour County, AL, Bibb County, AL, Bullock County, AL, Chambers County, AL, Chilton County, AL, Clay County, AL, Coosa County, AL, Dallas County, AL, Elmore County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, Sumter County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Wilcox County, AL, Kemper County, MS, Lauderdale County, MS, Lowndes County, MS, Noxubee County, MS

The radar

The Birmingham radar (KBMX), 49 km from the middle of the area, began a volume at 08:16 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, 8.3 hours before the alert went out and 49 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 2009-02-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 30 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 2009-02-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -133 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
30 J/kg
Mixed-layer CIN
-66 J/kg
Mixed-layer LCL
539 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
-133 m²/s²
0-3 km storm-relative helicity
61 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
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, 2:52 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, 3:57 PM CSTMesoscale DiscussionSPCColbert, Lauderdale4 hr
Feb 28, 5:43 PM CSTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston8 hr

Nearby

Mesoscale 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.