Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 685

May 3, 200912 counties in Alabama; 12 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 3, 2009, 7:18 AM CDT for 12 counties in Alabama; 12 counties in Mississippi. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
May 3, 2009, 7:18 AM CDT (12:18 UTC)
Expired
May 3, 2009, 8:15 AM CDT
In force
57 min
Issued by
the Storm Prediction Center
All 24 counties

Bibb County, AL, Chilton County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Attala County, MS, Kemper County, MS, Lauderdale County, MS, Leake County, MS, Lowndes County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Rankin County, MS, Scott County, MS, Winston County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 111 km from the middle of the area, began a volume at 12:19 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

Jackson, MS (KJAN), launched 12:00Z, 0.3 hours before the alert went out and 118 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, Jackson, MS at 12:00Z on 2009-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1741 joules per kilogram.LCLEL10008507005003002001001 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, Jackson, MS at 12:00Z on 2009-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 200 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
1741 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
484 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
200 m²/s²
0-3 km storm-relative helicity
237 m²/s²
Significant tornado parameter
2.4
Supercell composite
9.4

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
May 2, 7:30 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Clay, Cullman, Etowah and 12 more60 min
May 2, 8:43 PM CDTTornado WatchSPCBibb, Blount, Chilton, Fayette, Greene, Hale and 9 more6 hr
May 2, 10:40 PM CDTMesoscale DiscussionSPCBibb, Greene, Hale, Jefferson, Pickens, Tuscaloosa2 hr
May 3, 7:44 AM CDTSevere Thunderstorm WatchSPCBibb, Chilton, Fayette, Greene, Hale, Jefferson and 8 more8 hr
May 3, 9:24 AM CDTMesoscale DiscussionSPCChoctaw, Greene, Hale, Lamar, Marengo, Perry and 3 more66 min
May 3, 10:56 AM CDTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Butler, Calhoun and 39 more64 min
May 3, 11:35 AM CDTSevere Thunderstorm WatchSPCAutauga, Baldwin, Barbour, Blount, Bullock, Butler and 29 more5 hr
May 3, 1:49 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Bullock, Butler, Calhoun, Chambers and 22 more56 min
May 3, 3:11 PM CDTSevere Thunderstorm WatchSPCCoffee, Dale, Geneva, Henry, Houston3 hr
May 3, 3:13 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Calhoun, Chambers, Cherokee, Clay and 16 more62 min
May 3, 5:36 PM CDTMesoscale DiscussionSPCHenry84 min
May 3, 2:39 AM CDTMesoscale DiscussionSPCIssaquena, Washington2 hr
May 3, 6:54 AM CDTMesoscale DiscussionSPCAdams, Amite, Claiborne, Franklin, Jefferson, Warren and 1 more2 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.