Alert archive / Louisiana / Mesoscale Discussions in 2012
Mesoscale Discussion 412
The Storm Prediction Center issued this mesoscale discussion at Apr 2, 2012, 9:57 AM CDT for 33 parishes in Louisiana; 11 counties in Texas. It was in force for 63 min.
The area
The outline as issued.
The facts
- Issued
- Apr 2, 2012, 9:57 AM CDT (14:57 UTC)
- Expired
- Apr 2, 2012, 11:00 AM CDT
- In force
- 63 min
- Issued by
- the Storm Prediction Center
All 44 counties
Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, De Soto Parish, LA, East Baton Rouge Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Saint James Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Angelina County, TX, Hardin County, TX, Jasper County, TX, Nacogdoches County, TX, Newton County, TX, Orange 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), 56 km from the middle of the area, began a volume at 14:59 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, 3.0 hours before the alert went out and 56 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
- 3588 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 441 m above ground
- 0-6 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- 104 m²/s²
- 0-3 km storm-relative helicity
- 119 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
695
ACUS11 KWNS 021457
SWOMCD
SPC MCD 021457
LAZ000-MSZ000-TXZ000-021600-
MESOSCALE DISCUSSION 0412
NWS STORM PREDICTION CENTER NORMAN OK
0957 AM CDT MON APR 02 2012
AREAS AFFECTED...SERN TX INTO SWRN LA
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 021457Z - 021600Z
MCS CROSSING THE UPPER TX COAST/SABINE RIVER VALLEY ATTM IS EXPECTED
TO INTENSIFY OVER THE NEXT FEW HOURS...WITH DAMAGING WIND/HAIL
POTENTIAL FORECAST TO INCREASE. WW WILL LIKELY BE ISSUED IN THE
NEXT HOUR.
LATEST RADAR SHOWS A BOWING LINE OF STORMS AT THE LEADING EDGE OF AN
ONGOING MCS MOVING ENEWD ALONG THE TX COAST ATTM. AIRMASS HEAD OF
THE CONVECTION IS QUITE UNSTABLE...WITH LOW 70S DEWPOINTS BENEATH
STEEP MID-TROPOSPHERIC LAPSE RATES YIELDING OVER 3000 J/KG
MIXED-LAYER CAPE ACROSS SRN LA AND VICINITY. AS DAYTIME HEATING OF
THE CLOUD-FREE BOUNDARY LAYER AHEAD OF THE SYSTEM CONTINUES --
ADDITIONAL DESTABILIZATION WILL FURTHER SUPPORT INTENSIFICATION OF
THE ONGOING STORMS.
WHILE FLOW ALOFT REMAINS RELATIVELY WEAK AHEAD OF THE SYSTEM...THE
WELL-ORGANIZED NATURE OF THE MCS AND ASSOCIATED COLD POOL -- WITH 40
KT REAR INFLOW JET NOTED ON KHGZ /HOUSTON TX/ WSR-88D VWP SUGGESTS
CONTINUED FORWARD PROPAGATION OF THE SYSTEM -- WITH DAMAGING GUSTS
INCREASINGLY LIKELY AS STORMS INTENSIFY THROUGH THE MORNING.
..GOSS.. 04/02/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...JAN...LIX...LCH...SHV...HGX...FWD...
LAT...LON 29589349 30689497 31759533 32549308 31829192 29539043
29249127 29589349SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 2, 10:10 AM CDT | Severe Thunderstorm Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 31 more | 7 hr |
| Apr 2, 12:15 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Avoyelles, Bienville, Bossier and 49 more | 90 min |
| Apr 2, 12:41 PM CDT | Severe Thunderstorm Watch | SPC | Claiborne, Lincoln, Ouachita, Union, Webster | 6 hr |
| Apr 2, 12:50 PM CDT | Severe Thunderstorm Watch | SPC | Ascension, Assumption, Catahoula, Concordia, East Baton Rouge, East Carroll and 25 more | 7 hr |
| Apr 2, 3:18 PM CDT | Mesoscale Discussion | SPC | Union | 117 min |
| Apr 2, 3:23 PM CDT | Mesoscale Discussion | SPC | East Carroll, East Feliciana, Livingston, Madison, Morehouse, Orleans and 9 more | 2 hr |
| Apr 2, 5:36 PM CDT | Mesoscale Discussion | SPC | Orleans, Saint Bernard, Saint Tammany | 54 min |
| Apr 2, 5:16 AM CDT | Mesoscale Discussion | SPC | Austin, Brazoria, Chambers, Colorado, Fayette, Fort Bend and 13 more | 2 hr |
| Apr 2, 3:00 PM CDT | Mesoscale Discussion | SPC | Baylor, Childress, Collingsworth, Foard, Hardeman, Hemphill and 7 more | 2 hr |
| Apr 2, 3:37 PM CDT | Severe Thunderstorm Watch | SPC | Archer, Baylor, Brown, Callahan, Clay, Coleman and 28 more | 7 hr |
| Apr 2, 6:51 PM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Brown, Callahan, Clay, Coleman and 17 more | 54 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.