Alert archive / Louisiana / Mesoscale Discussions in 2006
Mesoscale Discussion 331
The Storm Prediction Center issued this mesoscale discussion at Mar 20, 2006, 9:20 AM CST for 18 parishes in Louisiana; 8 counties in Mississippi; 7 counties in Texas. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Mar 20, 2006, 9:20 AM CST (15:20 UTC)
- Expired
- Mar 20, 2006, 10:45 AM CST
- In force
- 85 min
- Issued by
- the Storm Prediction Center
All 33 counties
Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Jefferson Davis Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Tangipahoa Parish, LA, Vernon Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Franklin County, MS, Lawrence County, MS, Lincoln County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS, Hardin County, TX, Jasper County, TX, Liberty County, TX, Newton County, TX, Polk County, TX, Sabine County, TX, Tyler County, TX
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, 3.3 hours before the alert went out and 97 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
- 175 J/kg
- Mixed-layer CIN
- -190 J/kg
- Mixed-layer LCL
- 896 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 216 m²/s²
- 0-3 km storm-relative helicity
- 283 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.9
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 201520 SWOMCD SPC MCD 201520 MSZ000-LAZ000-TXZ000-201645- MESOSCALE DISCUSSION 0331 NWS STORM PREDICTION CENTER NORMAN OK 0920 AM CST MON MAR 20 2006 AREAS AFFECTED...SERN TX / CNTRL AND SRN LA / SRN MS CONCERNING...TORNADO WATCH 101... VALID 201520Z - 201645Z WW 101 WILL EXPIRE AT 16Z AND A REPLACEMENT TORNADO WATCH WILL LIKELY BE REQUIRED. AS OF 15Z...REGIONAL RADAR IMAGERY SHOWED A CLUSTER OF STRONG TO POTENTIALLY SEVERE /SLIGHTLY ELEVATED/ TSTMS FROM NEAR LFK SWD TO 40 NW BPT EXTENDING EWD INTO CNTRL LA NEAR ESF. MESOANALYSIS AND VAD DATA INDICATE THAT THESE STORMS ARE LIKELY BEING DRIVEN BY LOW-LEVEL WAA ALONG AND JUST TO THE N OF WARM FRONTAL/OUTFLOW COMPOSITE BOUNDARY EXTENDING FROM NW OF BPT TO JUST N OF MCB. A MOIST LOW-LEVEL AIR MASS EXISTS S OF THIS BOUNDARY...CHARACTERIZED BY DEWPOINTS OF 65-70 F. THIS MOISTURE COUPLED WITH INCREASED DIABATIC HEATING ARE CONTRIBUTING TO A MODERATELY UNSTABLE AIR MASS ACROSS WARM SECTOR WITH MLCAPES OF 1000-1500 J/KG. THIS INSTABILITY IN CONJUNCTION WITH RELATIVELY STRONG LOW AND DEEP-LAYER SHEAR /I.E. 0-1 KM SRH OF 300-400 M2/S2 AND EFFECTIVE BULK SHEAR OF 50-60 KTS/ ARE RESULTING IN AN ENVIRONMENT FAVORABLE FOR SUPERCELLS CAPABLE OF ISOLATED TORNADOES...PRIMARILY ALONG OR JUST TO THE S OF THIS W-E ORIENTED BAROCLINIC ZONE...WHICH IS EXPECTED TO LIFT SLOWLY NWD. LARGE HAIL AND DAMAGING WINDS WILL ALSO BE POSSIBLE WITH THE STRONGEST STORMS. FARTHER TO THE W...ADDITIONAL STRONG TO SEVERE STORMS HAVE RECENTLY DEVELOPED ALONG COLD FRONT NW OF UTS. GIVEN THE RELATIVE CLOSE PROXIMITY OF THESE STORMS TO COLD POOL EMANATING FROM AFOREMENTIONED TSTM CLUSTER...THIS ACTIVITY WILL LIKELY BECOME SLIGHTLY ELEVATED WITH TIME WITH A THREAT OF ISOLATED LARGE HAIL. THE APPARENT GREATER SEVERE THREAT HERE WOULD BE ALONG SRN EXTENSION OF COLD FRONT NE OF PSX WHERE INFLOW AIR MASS REMAINS UNCONTAMINATED. ..MEAD.. 03/20/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...JAN...LIX...LCH...SHV...HGX... 30129498 31039501 31379398 31729105 31729009 31188998 30479049 30139370
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 20, 3:36 AM CST | Mesoscale Discussion | SPC | Beauregard, Calcasieu | 24 min |
| Mar 20, 4:21 AM CST | Mesoscale Discussion | SPC | Allen, Avoyelles, Beauregard, Calcasieu, Evangeline, Grant and 6 more | 24 min |
| Mar 20, 4:44 AM CST | Tornado Watch | SPC | Allen, Avoyelles, Beauregard, Evangeline, Rapides, Saint Landry and 1 more | 5 hr |
| Mar 20, 6:36 AM CST | Mesoscale Discussion | SPC | Acadia, Allen, Beauregard, Evangeline, Rapides, Vernon | 54 min |
| Mar 20, 9:53 AM CST | Tornado Watch | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Catahoula and 19 more | 7 hr |
| Mar 20, 2:12 PM CST | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Catahoula and 19 more | 93 min |
| Mar 20, 3:09 PM CST | Tornado Watch | SPC | Ascension, East Baton Rouge, East Feliciana, Iberville, Livingston, Pointe Coupee and 6 more | 7 hr |
| Mar 20, 5:47 PM CST | Mesoscale Discussion | SPC | George, Greene, Hancock, Harrison, Jackson, Pearl River and 2 more | 118 min |
| Mar 19, 6:09 PM CST | Severe Thunderstorm Watch | SPC | Andrews, Bailey, Castro, Cochran, Crane, Deaf Smith and 12 more | 7 hr |
| Mar 19, 8:34 PM CST | Tornado Watch | SPC | Atascosa, Austin, Bandera, Bastrop, Bell, Bexar and 39 more | 7 hr |
| Mar 19, 8:54 PM CST | Mesoscale Discussion | SPC | Andrews, Bailey, Castro, Cochran, Crosby, Dawson and 17 more | 2 hr |
| Mar 19, 9:48 PM CST | Severe Thunderstorm Watch | SPC | Baylor, Borden, Briscoe, Callahan, Childress, Coke and 33 more | 5 hr |
| Mar 19, 10:32 PM CST | Mesoscale Discussion | SPC | Atascosa, Austin, Bandera, Bastrop, Bexar, Brazos and 28 more | 118 min |
| Mar 19, 11:37 PM CST | Mesoscale Discussion | SPC | Atascosa, Austin, Bandera, Bastrop, Bexar, Brazos and 28 more | 83 min |
| Mar 20, 1:26 AM CST | Mesoscale Discussion | SPC | Angelina, Aransas, Atascosa, Austin, Bastrop, Bee and 59 more | 64 min |
| Mar 20, 2:08 AM CST | Mesoscale Discussion | SPC | Baylor, Callahan, Childress, Coke, Coleman, Cottle and 17 more | 67 min |
| Mar 20, 12:47 PM CST | Mesoscale Discussion | SPC | Clay, Hardeman, Montague, Wichita, Wilbarger | 88 min |
Nearby
Mesoscale Discussions in Louisiana, 2006Mesoscale Discussions in Mississippi, 2006Mesoscale Discussions in Texas, 2006Every mesoscale discussion in 2006
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.