Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 528

April 19, 200926 counties in Alabama; George County, Greene County, Wayne County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2009, 4:46 PM CDT for 26 counties in Alabama; George County, Greene County, Wayne County, Mississippi. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued
Apr 19, 2009, 4:46 PM CDT (21:46 UTC)
Expired
Apr 19, 2009, 6:15 PM CDT
In force
89 min
Issued by
the Storm Prediction Center
All 29 counties

Baldwin County, AL, Bibb County, AL, Butler County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Dallas County, AL, Escambia County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Marengo County, AL, Marion County, AL, Mobile County, AL, Monroe County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Winston County, AL, George County, MS, Greene County, MS, Wayne County, MS

The radar

The Birmingham radar (KBMX), 122 km from the middle of the area, began a volume at 21:48 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 12:00Z, 9.8 hours before the alert went out and 122 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 2009-04-19Temperature 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 2009-04-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 109 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
2056 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
136 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
Apr 19, 12:43 PM CDTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Fayette, Greene, Hale and 9 more3 hr
Apr 19, 2:19 PM CDTTornado WatchSPCAutauga, Baldwin, Barbour, Bibb, Blount, Bullock and 43 more7 hr
Apr 19, 4:30 PM CDTSevere Thunderstorm WatchSPCColbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more5 hr
Apr 19, 6:51 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Bullock, Butler, Chilton, Clarke and 19 more54 min
Apr 19, 12:14 PM CDTMesoscale DiscussionSPCCoahoma, DeSoto, Tunica61 min
Apr 19, 1:17 PM CDTSevere Thunderstorm WatchSPCAlcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more6 hr
Apr 19, 2:22 PM CDTMesoscale DiscussionSPCAlcorn, Benton, Bolivar, Calhoun, Chickasaw, Coahoma and 15 more53 min
Apr 19, 3:49 PM CDTMesoscale DiscussionSPCAlcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 13 more56 min
Apr 19, 5:47 PM CDTMesoscale DiscussionSPCAlcorn, Calhoun, Chickasaw, Itawamba, Lee, Monroe and 5 more58 min

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.