Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 241
The Storm Prediction Center issued this mesoscale discussion at Mar 11, 2012, 11:31 AM CDT for 5 parishes in Louisiana; 15 counties in Texas. It was in force for 89 min.
The area
The outline as issued.
The facts
- Issued
- Mar 11, 2012, 11:31 AM CDT (16:31 UTC)
- Expired
- Mar 11, 2012, 1:00 PM CDT
- In force
- 89 min
- Issued by
- the Storm Prediction Center
Counties Bossier Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Red River Parish, LA, Sabine Parish, LA, Angelina County, TX, Chambers County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Panola County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Tyler County, TX
The radar
The Lake Charles radar (KLCH), 134 km from the middle of the area, began a volume at 16:34 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
Lake Charles Mun, LA (KLCH), launched 12:00Z, 4.5 hours before the alert went out and 135 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.
- Mixed-layer CAPE
- 182 J/kg
- Mixed-layer CIN
- -71 J/kg
- Mixed-layer LCL
- 452 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 246 m²/s²
- 0-3 km storm-relative helicity
- 294 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.1
The text
As transmitted, in the capitals the NWS used until 2016.
441
ACUS11 KWNS 111632
SWOMCD
SPC MCD 111631
LAZ000-TXZ000-111800-
MESOSCALE DISCUSSION 0241
NWS STORM PREDICTION CENTER NORMAN OK
1131 AM CDT SUN MAR 11 2012
AREAS AFFECTED...ERN TX INTO NWRN LA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 111631Z - 111800Z
RECENT TRENDS HAVE BEEN FOR STORMS MOVING INTO SERN TX TO INCREASE
IN INTENSITY. THIS ACTIVITY COULD BECOME CAPABLE OF PRODUCING
ISOLATED DAMAGING WIND AND PERHAPS A COUPLE OF TORNADOES. CONVECTIVE
TRENDS ARE BEING MONITORED FOR A POSSIBLE WW.
TREND HAS BEEN FOR STORMS DEVELOPING ALONG PRE-FRONTAL CONVERGENCE
BAND FROM WEST OF THE HOUSTON METRO AREA NWD TO NEAR HUNTSVILLE TO
INTENSIFY AND BECOME A LITTLE BETTER ORGANIZED AS LINES. THE RECENT
INTENSIFICATION APPEARS TO BE OCCURRING AS THE CONVERGENCE BAND
BEGINS TO INTERACT WITH THE THETA-E AXIS WITH DEWPOINTS IN THE UPPER
60S AND TEMPERATURES IN THE LOW 70S SUPPORTING 500-800 J/KG MLCAPE
OVER SERN TX. THE ATMOSPHERE SHOULD DESTABILIZE SLOWLY NWD WITH
TIME. VWP DATA INDICATE 0-1 KM STORM RELATIVE HELICITY ON THE ORDER
OF 150-200 M2/S2 AND 0-6 KM SHEAR FROM 35-45 KT. TENDENCY WILL BE
FOR LOW LEVEL FLOW TO GRADUALLY DECREASE ACROSS SERN TX AS THE LLJ
SHIFTS NWD INTO THE LOWER MS VALLEY. HOWEVER...VERTICAL WIND
PROFILES WILL REMAIN SUFFICIENT FOR EMBEDDED ORGANIZED STORM
STRUCTURES INCLUDING SUPERCELLS AND BOWING SEGMENTS NEXT FEW HOURS.
..DIAL.. 03/11/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LCH...SHV...HGX...
LAT...LON 29389509 29999533 32509432 32809338 31799333 29899396
29389509SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 11, 11:55 AM CDT | Tornado Watch | SPC | Allen, Beauregard, Bienville, Bossier, Caddo, Calcasieu and 18 more | 7 hr |
| Mar 11, 2:47 PM CDT | Mesoscale Discussion | SPC | Allen, Beauregard, Bienville, Calcasieu, De Soto, Grant and 10 more | 118 min |
| Mar 11, 5:36 PM CDT | Mesoscale Discussion | SPC | Avoyelles, Caldwell, Catahoula, Concordia, East Carroll, Franklin and 12 more | 84 min |
| Mar 11, 6:42 PM CDT | Tornado Watch | SPC | Acadia, Allen, Avoyelles, Caldwell, Cameron, Catahoula and 20 more | 8 hr |
| Mar 11, 7:56 AM CDT | Mesoscale Discussion | SPC | Angelina, Brazoria, Chambers, Fort Bend, Galveston, Hardin and 15 more | 3 hr |
Nearby
Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Louisiana, 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.