Alert archive / Mississippi / Mesoscale Discussions in 2004

Mesoscale Discussion 85

February 5, 2004Choctaw County, Washington County, Alabama; 17 parishes in Louisiana; 22 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 5, 2004, 9:52 AM CST for Choctaw County, Washington County, Alabama; 17 parishes in Louisiana; 22 counties in Mississippi. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Feb 5, 2004, 9:52 AM CST (15:52 UTC)
Expired
Feb 5, 2004, 11:45 AM CST
In force
113 min
Issued by
the Storm Prediction Center
All 41 counties

Choctaw County, AL, Washington County, AL, Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Clarke County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS

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 12:00Z, 3.9 hours before the alert went out and 59 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 12:00Z on 2004-02-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 772 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 12:00Z on 2004-02-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 338 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
772 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
446 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
338 m²/s²
0-3 km storm-relative helicity
542 m²/s²
Significant tornado parameter
0.0
Supercell composite
7.2

Open this sounding in Storm Lab

The text

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

638 
ACUS11 KWNS 051553
SWOMCD
SPC MCD 051552 
ALZ000-MSZ000-LAZ000-051745-

MESOSCALE DISCUSSION 0085
NWS STORM PREDICTION CENTER NORMAN OK
0952 AM CST THU FEB 05 2004

AREAS AFFECTED...SERN LA...SRN/CNTRL MS....WRN AL

CONCERNING...HEAVY RAINFALL...TORNADO WATCH 5...

VALID 051552Z - 051745Z

SLOW MOVING AND INTENSE FRONTAL BOUNDARY WILL CONTINUE TO MOVE
GRADUALLY EAST ACROSS SRN MS AND SERN LA THROUGH THE REST OF THE DAY
AND PROVIDE A FOCUS FOR TRAINING STRONG TO SEVERE TSTMS. LATEST
INDICATIONS ARE THAT A NEW WATCH WILL PROBABLY BE NEEDED ACROSS
PORTIONS OF SERN LA/SERN MS...AND PERHAPS WRN AL PRIOR TO 18Z/NOON
CST.

FRONT WAS ALIGNED WITHIN INVERTED SURFACE TROUGH FROM SE OF LCH TO
NEAR JAN AT 15Z. SEVERAL SMALL SCALE FRONTAL WAVES ARE EVIDENT ALONG
THE BOUNDARY WITH ONE TO THE NE OF LCH AND ANOTHER NEAR THE INVERTED
TROUGH APEX NORTH OF JAN. AIRMASS AHEAD OF THE LINE OF FORCING WILL
REMAIN ONLY MARGINALLY UNSTABLE. HOWEVER...IT APPEARS THAT
SUFFICIENTLY FORCED SLAB ASCENT...WEAKENING SURFACE-BASED
INVERSION...AND STRONG SHEAR WITHIN THE WARM SECTOR WILL ALL
CONTRIBUTE TO SEVERE WIND AND ISOLD/BRIEF TORNADO POTENTIAL FROM
SUPERCELLS TRACKING NEWD ALONG/NEAR THE BOUNDARY OVER THE NEXT FEW
HOURS. THIS POTENTIAL IS PROBABLY GREATEST FROM EAST-CNTRL MS SWD
ACROSS SERN LA.

IN ADDITION...ALIGNMENT OF THE SURFACE BAROCLINIC ZONE TO THE DEEP
SWLY MEAN LAYER FLOW...AND INTENSE LOW LEVEL MOISTURE CONVERGENCE
ALONG THE SLOW MOVING BOUNDARY...SUGGEST THAT TRAINING CONVECTION
AND EXCESSIVE RAINFALL THREAT WILL CONTINUE TO DEVELOP ESEWD ACROSS
LA AND MS THROUGH THE DAY WITH RAINFALL RATES IN SOME LOCATIONS
APPROACHING 2 INCHES PER HOUR.

..CARBIN.. 02/05/2004

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

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

29519094 29719231 31369048 32458895 32348795 31098802
30258852

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 5, 11:35 AM CSTTornado WatchSPCAutauga, Chilton, Choctaw, Clarke, Dallas, Greene and 6 more5 hr
Feb 5, 1:11 PM CSTMesoscale DiscussionSPCChoctaw, Clarke, Greene, Hale, Marengo, Perry and 2 more2 hr
Feb 5, 3:22 PM CSTMesoscale DiscussionSPCChoctaw, Marengo, Sumter113 min
Feb 5, 4:43 PM CSTMesoscale DiscussionSPCAutauga, Chilton, Choctaw, Clarke, Dallas, Greene and 6 more32 min
Feb 5, 4:55 PM CSTTornado WatchSPCBibb, Chilton, Choctaw, Clarke, Dallas, Greene and 10 more6 hr
Feb 4, 11:37 PM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Evangeline and 10 more83 min
Feb 5, 1:16 AM CSTMesoscale DiscussionSPCBeauregard, Bienville, De Soto, Grant, Jackson, Lincoln and 6 more119 min
Feb 5, 5:08 AM CSTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 27 more3 hr
Feb 5, 5:40 AM CSTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 33 more6 hr
Feb 5, 7:35 AM CSTMesoscale DiscussionSPCAcadia, Calcasieu, Cameron, East Baton Rouge, East Feliciana, Evangeline and 11 more115 min
Feb 5, 8:02 AM CSTMesoscale DiscussionSPCAcadia, Calcasieu, Cameron, East Baton Rouge, East Feliciana, Evangeline and 11 more118 min

Nearby

Mesoscale Discussions in Mississippi, 2004Mesoscale Discussions in Louisiana, 2004Mesoscale Discussions in Alabama, 2004Every mesoscale discussion in 2004

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.