Alert archive / Alabama / Mesoscale Discussions in 2003

Mesoscale Discussion 424

April 6, 200312 counties in Alabama; 11 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2003, 9:48 PM CDT for 12 counties in Alabama; 11 counties in Mississippi. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued
Apr 6, 2003, 9:48 PM CDT (02:48 UTC)
Expired
Apr 6, 2003, 11:15 PM CDT
In force
87 min
Issued by
the Storm Prediction Center
All 23 counties

Autauga County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Dallas County, AL, Hale County, AL, Marengo County, AL, Monroe County, AL, Perry County, AL, Sumter County, AL, Washington County, AL, Wilcox County, AL, Clarke County, MS, Covington County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lauderdale County, MS, Neshoba County, MS, Newton County, MS, Smith County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 156 km from the middle of the area, began a volume at 02:48 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

Jackson, MS (KJAN), launched 00:00Z, 2.8 hours before the alert went out and 179 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 00:00Z on 2003-04-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 614 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, Jackson, MS at 00:00Z on 2003-04-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 417 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
614 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
742 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
417 m²/s²
0-3 km storm-relative helicity
582 m²/s²
Significant tornado parameter
1.9
Supercell composite
7.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

136 
ACUS11 KWNS 070249
SWOMCD
SPC MCD 070248 
ALZ000-MSZ000-070415-

MESOSCALE DISCUSSION 0424
NWS STORM PREDICTION CENTER NORMAN OK
0948 PM CDT SUN APR 06 2003

AREAS AFFECTED...NERN LA...SWRN THROUGH CNTRL MS AND S
CNTRL/CNTRL AL

CONCERNING...TORNADO WATCH 108...

VALID 070248Z - 070415Z

PRIMARY SEVERE THREAT IS EXPECTED TO REMAIN WITH LONG LIVED
ISOLATED SUPERCELL AS IT CONTINUES EWD THROUGH SERN MS. THREAT OF
A SIGNIFICANT TORNADO MAY PERSIST WITH THIS STORM ANOTHER FEW
HOURS. THE STORM IS MOVING EWD AT AROUND 30 KT AND IF IT HOLDS
TOGETHER... WILL BEGIN TO CROSS INTO SWRN AL AROUND 04Z. CURRENT
THINKING IS THAT TORNADO WATCH 108 MAY BE REPLACED BY ANOTHER
TORNADO WATCH AROUND 0330Z THAT WILL ONLY INCLUDE A PART OF SWRN
THROUGH S CNTRL AL.

..DIAL.. 04/07/2003

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BMX...MOB...JAN...

31718680 31398761 31348944 31428993 31918983 32508938
32838911 32828816 32898653 32438658

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 6, 8:13 PM CDTMesoscale DiscussionSPCBibb, Chilton, Choctaw, Dallas, Fayette, Greene and 8 more2 hr
Apr 6, 10:15 PM CDTTornado WatchSPCAutauga, Butler, Choctaw, Clarke, Conecuh, Covington and 10 more5 hr
Apr 6, 11:39 PM CDTMesoscale DiscussionSPCAutauga, Butler, Choctaw, Clarke, Conecuh, Covington and 11 more2 hr
Apr 7, 1:51 AM CDTMesoscale DiscussionSPCBullock, Butler, Lowndes, Macon, Montgomery54 min
Apr 7, 2:55 AM CDTTornado WatchSPCAutauga, Barbour, Bullock, Chilton, Choctaw, Dallas and 13 more4 hr
Apr 7, 4:49 AM CDTMesoscale DiscussionSPCAutauga, Chambers, Chilton, Coosa, Dallas, Elmore and 11 more3 hr
Apr 7, 9:11 AM CDTMesoscale DiscussionSPCBarbour, Coffee, Conecuh, Covington, Crenshaw, Dale and 6 more3 hr
Apr 7, 9:40 AM CDTTornado WatchSPCBarbour, Bullock, Macon, Pike, Russell5 hr
Apr 7, 11:25 AM CDTMesoscale DiscussionSPCBaldwin, Butler, Clarke, Coffee, Conecuh, Covington and 6 more3 hr
Apr 7, 12:07 PM CDTMesoscale DiscussionSPCBaldwin, Butler, Clarke, Coffee, Conecuh, Covington and 6 more113 min
Apr 7, 12:22 PM CDTMesoscale DiscussionSPCBaldwin, Butler, Clarke, Coffee, Conecuh, Covington and 6 more113 min
Apr 7, 3:40 PM CDTSevere Thunderstorm WatchSPCBaldwin, Covington, Escambia, Mobile5 hr
Apr 7, 5:58 PM CDTMesoscale DiscussionSPCBaldwin, Escambia, Mobile2 hr
Apr 7, 10:05 AM CDTSevere Thunderstorm WatchSPCAmite, Forrest, George, Greene, Hancock, Harrison and 11 more6 hr
Apr 7, 11:02 AM CDTMesoscale DiscussionSPCForrest, Lamar, Pearl River, Perry, Stone3 hr
Apr 7, 2:13 PM CDTMesoscale DiscussionSPCHancock, Harrison, Pearl River, Perry, Stone3 hr
Apr 7, 2:36 PM CDTMesoscale DiscussionSPCHancock, Harrison, Pearl River, Perry, Stone114 min

Nearby

Mesoscale Discussions in Alabama, 2003Mesoscale Discussions in Mississippi, 2003Every mesoscale discussion in 2003

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.