Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 1139

June 12, 201211 parishes in Louisiana; 7 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jun 12, 2012, 12:12 PM CDT for 11 parishes in Louisiana; 7 counties in Texas. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued
Jun 12, 2012, 12:12 PM CDT (17:12 UTC)
Expired
Jun 12, 2012, 1:15 PM CDT
In force
63 min
Issued by
the Storm Prediction Center

Counties Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Chambers County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 16 km from the middle of the area, began a volume at 17:15 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 5.2 hours before the alert went out and 17 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, Lake Charles Mun, LA at 12:00Z on 2012-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3877 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, Lake Charles Mun, LA at 12:00Z on 2012-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -3 square meters per square second.1939Sfc1 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
3877 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
540 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
49 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

645 
ACUS11 KWNS 121712
SWOMCD
SPC MCD 121712 
LAZ000-TXZ000-121815-

MESOSCALE DISCUSSION 1139
NWS STORM PREDICTION CENTER NORMAN OK
1212 PM CDT TUE JUN 12 2012

AREAS AFFECTED...TX...LA

CONCERNING...SEVERE THUNDERSTORM WATCH 380...

VALID 121712Z - 121815Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 380
CONTINUES.

SUMMARY...THE THREAT FOR ISOLATED STRONG WINDS AND SOME HAIL WILL
PERSIST ACROSS VALID PORTIONS OF THE WATCH AREA.

DISCUSSION...LOOSELY ORGANIZED LINEAR CONVECTIVE SYSTEM CONTINUES TO
SPREAD SOUTH INTO SWRN LA AND EXTREME ERN TX EARLY THIS AFTERNOON.
STRONG INSTABILITY HAS DEVELOPED ALONG THE SWN FLANK OF THE SYSTEM
WHERE RECENT INCREASE IN CONVECTIVE VIGOR HAS BEEN NOTED OVER TYLER
COUNTY TX. ELSEWHERE...STORMS HAVE BECOME OUTFLOW DOMINANT ACROSS
SWRN LA WHERE WIND SHIFT HAS TRACKED SOUTH AT ABOUT 26KT AHEAD OF
THE DEEPER CONVECTION TO ITS NORTH. OVERALL...SEVERE THREATS IN THE
FORMS OF HAIL/WIND OF WILL PROBABLY REMAIN QUITE ISOLATED FOR THE
REMAINDER OF THE WATCH VALID TIME. LOCAL HEAVY RAIN IS CERTAINLY A
CONCERN GIVEN SLOW MOVEMENT AND TRAINING OF STORMS IN A VERY MOIST
ENVIRONMENT.

..CARBIN.. 06/12/2012

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

ATTN...WFO...LIX...LCH...SHV...HGX...

LAT...LON   31099472 30409166 29849117 29499165 29559388 29599449
            29619471 31099472

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 11, 7:33 PM CDTMesoscale DiscussionSPCEast Carroll, Franklin, Madison, Morehouse, Richland, Tensas and 1 more57 min
Jun 11, 8:37 PM CDTSevere Thunderstorm WatchSPCCatahoula, Concordia, East Feliciana, Franklin, Saint Helena, Saint Tammany and 4 more4 hr
Jun 11, 10:51 PM CDTMesoscale DiscussionSPCEast Baton Rouge, East Feliciana, Saint Helena, Tangipahoa, Washington, West Baton Rouge and 1 more54 min
Jun 11, 11:52 PM CDTSevere Thunderstorm WatchSPCBossier, Caddo, Claiborne, Union, Webster6 hr
Jun 12, 2:54 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 15 more96 min
Jun 12, 3:21 AM CDTSevere Thunderstorm WatchSPCBienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 20 more8 hr
Jun 12, 6:08 AM CDTMesoscale DiscussionSPCBienville, Caldwell, Catahoula, Concordia, De Soto, East Carroll and 16 more2 hr
Jun 12, 7:11 AM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more8 hr
Jun 12, 9:23 AM CDTMesoscale DiscussionSPCGrant, LaSalle, Natchitoches, Sabine67 min
Jun 11, 7:11 PM CDTMesoscale DiscussionSPCBrown, Callahan, Clay, Coke, Coleman, Collin and 29 more94 min
Jun 11, 9:54 PM CDTMesoscale DiscussionSPCArcher, Baylor, Brown, Callahan, Clay, Coke and 31 more66 min
Jun 11, 11:29 PM CDTMesoscale DiscussionSPCGrayson61 min
Jun 12, 4:08 AM CDTMesoscale DiscussionSPCArmstrong, Bailey, Briscoe, Castro, Childress, Deaf Smith and 9 more2 hr
Jun 12, 10:32 AM CDTMesoscale DiscussionSPCArcher, Clay, Collin, Cooke, Dallas, Denton and 19 more88 min
Jun 12, 11:00 AM CDTSevere Thunderstorm WatchSPCAnderson, Bell, Bosque, Brown, Callahan, Collin and 36 more6 hr
Jun 12, 2:02 PM CDTMesoscale DiscussionSPCDallam, Deaf Smith, Hartley, Oldham88 min
Jun 12, 2:16 PM CDTSevere Thunderstorm WatchSPCDallam, Deaf Smith, Hartley, Oldham8 hr
Jun 12, 2:45 PM CDTMesoscale DiscussionSPCCoke, Coleman, Concho, Glasscock, Midland, Mitchell and 4 more60 min
Jun 12, 3:00 PM CDTMesoscale DiscussionSPCAndrews, Bailey, Cochran, Crane, Ector, Gaines and 7 more60 min
Jun 12, 3:28 PM CDTMesoscale DiscussionSPCAnderson, Bell, Bosque, Brazos, Brown, Burleson and 37 more62 min
Jun 12, 3:44 PM CDTSevere Thunderstorm WatchSPCAndrews, Bailey, Cochran, Crane, Culberson, Ector and 13 more8 hr
Jun 12, 3:56 PM CDTSevere Thunderstorm WatchSPCAnderson, Austin, Bell, Brazoria, Brazos, Burleson and 24 more4 hr
Jun 12, 5:42 PM CDTMesoscale DiscussionSPCDallam63 min

Nearby

Mesoscale Discussions in Louisiana, 2012Mesoscale Discussions in Texas, 2012Every mesoscale discussion in 2012

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.