Alert archive / Alabama / Mesoscale Discussions in 2003

Mesoscale Discussion 280

March 18, 200320 counties in Alabama; Escambia County, Florida; 8 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2003, 9:10 PM CST for 20 counties in Alabama; Escambia County, Florida; 8 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Mar 18, 2003, 9:10 PM CST (03:10 UTC)
Expired
Mar 18, 2003, 11:45 PM CST
In force
3 hr
Issued by
the Storm Prediction Center
All 29 counties

Autauga County, AL, Baldwin County, AL, Bibb County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Dallas County, AL, Escambia County, AL, Greene County, AL, Hale County, AL, Lowndes County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Perry County, AL, Pickens County, AL, Sumter County, AL, Tuscaloosa County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Clarke County, MS, George County, MS, Greene County, MS, Jackson County, MS, Kemper County, MS, Lauderdale County, MS, Perry County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 91 km from the middle of the area, began a volume at 03:12 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

Slidell Radar S, LA (KSIL), launched 00:00Z, 3.2 hours before the alert went out and 202 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 2003-03-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 394 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 2003-03-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 150 square meters per square second.1939587897117Sfc1 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
394 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
631 m above ground
0-6 km bulk shear
71 kt
0-1 km storm-relative helicity
150 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
0.3
Supercell composite
3.1

Open this sounding in Storm Lab

The text

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

152 
ACUS11 KWNS 190310
SWOMCD
SPC MCD 190310 
ALZ000-FLZ000-MSZ000-190545-

MESOSCALE DISCUSSION 0280
NWS STORM PREDICTION CENTER NORMAN OK
0910 PM CST TUE MAR 18 2003

AREAS AFFECTED...ERN AND SERN MS/SWRN AND WCNTRL AL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 190310Z - 190545Z

SQUALL-LINE WILL CONTINUE TO MOVE INTO ERN MS AND WRN AL OVER THE
NEXT COUPLE OF HOURS. WIND DAMAGE WILL BE POSSIBLE WITH
MULTICELLS IN THE LINE WITH TORNADO POTENTIAL IN ISOLATED
SUPERCELLS AHEAD OF THE LINE. A NEW TORNADO WATCH MAY BE REQUIRED
FARTHER E SOON.



THE STRENGTHENING LOW-LEVEL JET OVER ECNTRL MS OF 35 KNOTS AND
APPROACHING MID-LEVEL SPEED MAX OF 80 KNOTS OVER THE NWRN GULF OF
MEXICO WERE COMBINING TO CREATE FAVORABLE DEEP LAYER SHEAR FOR
SUPERCELLS ACROSS ERN MS AND WRN AL. REGIONAL VAD WIND PROFILES
SHOW STORM RELATIVE HELICITY VALUES HAVE INCREASED TO NEARLY 500
M2/S2 IN THE LAST COUPLE OF HOURS. DUE TO INCREASING LOW-LEVEL
WIND SHEAR PROFILES...CELLS THAT MAY DEVELOP AHEAD OF THE
SQUALL-LINE MOVING INTO ERN MS AND WRN AL WILL HAVE A POTENTIAL
FOR ISOLATED TORNADOES.

..BROYLES.. 03/19/2003

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

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

30388880 30748907 31468906 32348888 33058863 33488795
33328697 32278653 31078691 30328734 30278830 30348875

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 18, 6:39 PM CSTMesoscale DiscussionSPCButler, Choctaw, Clarke, Coffee, Conecuh, Covington and 13 more3 hr
Mar 18, 7:30 PM CSTTornado WatchSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 5 more6 hr
Mar 18, 10:25 PM CSTTornado WatchSPCBaldwin, Bibb, Choctaw, Clarke, Colbert, Cullman and 24 more7 hr
Mar 18, 11:50 PM CSTMesoscale DiscussionSPCBibb, Choctaw, Clarke, Colbert, Cullman, Fayette and 18 more115 min
Mar 19, 2:02 AM CSTMesoscale DiscussionSPCBibb, Choctaw, Clarke, Colbert, Cullman, Dallas and 22 more118 min
Mar 19, 7:10 AM CSTMesoscale DiscussionSPCMadison2 hr
Mar 19, 8:00 AM CSTTornado WatchSPCDeKalb, Jackson, Madison, Marshall, Morgan4 hr
Mar 19, 9:28 AM CSTMesoscale DiscussionSPCBlount, DeKalb, Jackson, Madison, Marshall2 hr
Mar 19, 11:30 AM CSTTornado WatchSPCDeKalb, Jackson, Marshall7 hr
Mar 19, 11:58 AM CSTMesoscale DiscussionSPCDeKalb, Etowah, Jackson, Marshall2 hr
Mar 19, 12:59 PM CSTMesoscale DiscussionSPCBarbour, Bullock, Dale, Henry, Houston, Lee and 4 more3 hr
Mar 19, 1:30 PM CSTTornado WatchSPCAutauga, Barbour, Bullock, Butler, Calhoun, Chambers and 15 more6 hr
Mar 19, 2:06 PM CSTMesoscale DiscussionSPCCalhoun, Cherokee, DeKalb, Etowah, Jackson, Marshall and 1 more114 min
Mar 19, 3:35 PM CSTMesoscale DiscussionSPCBarbour, Chambers, Lee, Macon, Randolph, Russell and 1 more115 min
Mar 19, 3:52 PM CSTMesoscale DiscussionSPCCalhoun, Cherokee, Cleburne, DeKalb, Etowah113 min
Mar 18, 11:53 PM CSTMesoscale DiscussionSPCHamilton, Jefferson, Leon, Madison, Taylor3 hr
Mar 19, 2:08 PM CSTMesoscale DiscussionSPCBrevard, Broward, Duval, Flagler, Glades, Hardee and 17 more3 hr
Mar 19, 5:32 PM CSTMesoscale DiscussionSPCBaker, Bradford, Brevard, Clay, Duval, Flagler and 10 more118 min
Mar 18, 6:08 PM CSTMesoscale DiscussionSPCAdams, Amite, Claiborne, Copiah, Franklin, Hinds and 13 more2 hr

Nearby

Mesoscale Discussions in Alabama, 2003Mesoscale Discussions in Mississippi, 2003Mesoscale Discussions in Florida, 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.