Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 309

March 27, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2009, 11:51 PM CDT for 4 states. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
Mar 27, 2009, 11:51 PM CDT (04:51 UTC)
Expired
Mar 28, 2009, 1:15 AM CDT
In force
84 min
Issued by
the Storm Prediction Center
All 34 counties

Autauga County, AL, Baldwin County, AL, Butler County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Greene County, AL, Hale County, AL, Lowndes County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Sumter County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, Saint Bernard Parish, LA, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Perry County, MS, Stone County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 70 km from the middle of the area, began a volume at 04:54 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

Slidell Radar S, LA (KSIL), launched 00:00Z, 4.9 hours before the alert went out and 213 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, Slidell Radar S, LA at 00:00Z on 2009-03-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1844 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, Slidell Radar S, LA at 00:00Z on 2009-03-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 259 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
1844 J/kg
Mixed-layer CIN
-27 J/kg
Mixed-layer LCL
467 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
259 m²/s²
0-3 km storm-relative helicity
296 m²/s²
Significant tornado parameter
2.8
Supercell composite
13.4

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
Mar 27, 8:21 PM CDTMesoscale DiscussionSPCBaldwin, Escambia, Mobile, Washington84 min
Mar 27, 10:09 PM CDTTornado WatchSPCAutauga, Baldwin, Butler, Choctaw, Clarke, Conecuh and 16 more9 hr
Mar 28, 1:17 AM CDTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston4 hr
Mar 28, 3:14 AM CDTMesoscale DiscussionSPCAutauga, Baldwin, Butler, Chilton, Choctaw, Clarke and 17 more61 min
Mar 28, 4:25 AM CDTMesoscale DiscussionSPCAutauga, Baldwin, Barbour, Bibb, Bullock, Butler and 45 more35 min
Mar 28, 4:50 AM CDTTornado WatchSPCBaldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 11 more5 hr
Mar 28, 4:59 AM CDTSevere Thunderstorm WatchSPCAutauga, Barbour, Bibb, Bullock, Calhoun, Chambers and 24 more3 hr
Mar 28, 6:48 AM CDTMesoscale DiscussionSPCBaldwin, Barbour, Coffee, Conecuh, Covington, Crenshaw and 6 more57 min
Mar 28, 9:20 AM CDTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston8 hr
Mar 28, 12:58 PM CDTMesoscale DiscussionSPCBlount, Colbert, Cullman, Jackson, Lauderdale, Lawrence and 5 more92 min
Mar 28, 2:23 PM CDTTornado WatchSPCCullman, DeKalb, Jackson, Lauderdale, Lawrence, Limestone and 3 more7 hr
Mar 28, 5:18 PM CDTMesoscale DiscussionSPCDeKalb, Jackson, Limestone, Madison, Marshall, Morgan57 min
Mar 28, 2:19 PM CDTMesoscale DiscussionSPCCalhoun, Franklin, Gadsden, Gulf, Hamilton, Jefferson and 5 more56 min
Mar 27, 7:51 PM CDTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 36 more9 hr
Mar 27, 10:24 PM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, East Carroll and 13 more96 min
Mar 27, 11:06 PM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Caldwell and 32 more84 min
Mar 28, 1:33 AM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 14 more27 min
Mar 28, 2:20 AM CDTTornado WatchSPCClarke, Covington, Forrest, Jasper, Jefferson Davis, Jones and 10 more3 hr

Nearby

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