Alert archive / Louisiana / Mesoscale Discussions in 2015
Mesoscale Discussion 1908
The Storm Prediction Center issued this mesoscale discussion at Oct 31, 2015, 10:03 AM CDT for 14 parishes in Louisiana; 12 counties in Texas. It was in force for 57 min.
The area
The outline as issued.
The facts
- Issued
- Oct 31, 2015, 10:03 AM CDT (15:03 UTC)
- Expired
- Oct 31, 2015, 11:00 AM CDT
- In force
- 57 min
- Issued by
- the Storm Prediction Center
All 26 counties
Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Brazoria County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jefferson County, TX, Liberty County, TX, Matagorda County, TX, Newton County, TX, Orange County, TX, Wharton County, TX
The radar
The Lake Charles radar (KLCH), 98 km from the middle of the area, began a volume at 15:07 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, 3.1 hours before the alert went out and 100 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
- 1182 J/kg
- Mixed-layer CIN
- -2 J/kg
- Mixed-layer LCL
- 503 m above ground
- 0-6 km bulk shear
- 62 kt
- 0-1 km storm-relative helicity
- 441 m²/s²
- 0-3 km storm-relative helicity
- 556 m²/s²
- Significant tornado parameter
- 4.0
- Supercell composite
- 15.9
The text
As transmitted, in the capitals the NWS used until 2016.
655
ACUS11 KWNS 311504
SWOMCD
SPC MCD 311503
LAZ000-TXZ000-311600-
MESOSCALE DISCUSSION 1908
NWS STORM PREDICTION CENTER NORMAN OK
1003 AM CDT SAT OCT 31 2015
AREAS AFFECTED...UPPER TX COAST AND LA
CONCERNING...TORNADO WATCH 526...527...
VALID 311503Z - 311600Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 526...527...CONTINUES.
SUMMARY...ISOLATED TORNADOES REMAIN POSSIBLE ACROSS THE UPPER TX
COAST AND OVER SOUTHERN LA.
DISCUSSION...N-S LINEAR CONVECTION THAT DEVELOPED DURING THE
OVERNIGHT HOURS ACROSS TX HAS PROGRESSED INTO THE UPPER TX COAST.
THIS ACTIVITY HAS CAUGHT UP WITH EARLIER TSTM COMPLEX THAT EVOLVED
OVER THE UPPER TX COAST/NWRN GULF BASIN. WHILE FLOW IS BEGINNING TO
VEER ACROSS THE UPPER TX COAST IT APPEARS THERE IS A NON-ZERO CHANCE
FOR AN ISOLATED TORNADO WITH SWRN PORTIONS OF SQUALL LINE AS IT
PROGRESSES TOWARD COASTAL LA. STRONGER LOW-LEVEL SHEAR IS NOW
FOCUSED OVER SRN/SERN LA...AND WHILE CONVECTIVE MODE IS CURRENTLY
LINEAR IN NATURE...ISOLATED SUPERCELLS COULD EVOLVE OVER THE WARM
SECTOR WHERE CONDITIONS REMAIN FAVORABLE FOR TORNADOES.
..DARROW.. 10/31/2015
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...JAN...LIX...LCH...SHV...HGX...
LAT...LON 29589645 30469418 29939393 31259391 31319168 29579169
29529375 28619597 29589645SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 31, 6:54 AM CDT | Tornado Watch | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more | 5 hr |
| Oct 31, 11:01 AM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, Avoyelles, East Baton Rouge, East Feliciana, Iberia and 18 more | 89 min |
| Oct 31, 11:45 AM CDT | Tornado Watch | SPC | Acadia, Ascension, Assumption, Avoyelles, Cameron, Concordia and 27 more | 8 hr |
| Oct 31, 1:35 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana and 22 more | 55 min |
| Oct 31, 3:36 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana and 22 more | 54 min |
| Oct 31, 5:42 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana and 22 more | 93 min |
| Oct 30, 8:22 PM CDT | Mesoscale Discussion | SPC | Bandera, Dimmit, Edwards, Gillespie, Kerr, Kimble and 12 more | 113 min |
| Oct 30, 11:15 PM CDT | Mesoscale Discussion | SPC | Bandera, Blanco, Edwards, Gillespie, Kendall, Kerr and 7 more | 2 hr |
| Oct 31, 1:17 AM CDT | Mesoscale Discussion | SPC | Bastrop, Bexar, Blanco, Burnet, Caldwell, Comal and 6 more | 58 min |
| Oct 31, 1:51 AM CDT | Mesoscale Discussion | SPC | Austin, Brazoria, Chambers, Colorado, Fort Bend, Harris and 3 more | 114 min |
| Oct 31, 2:57 AM CDT | Tornado Watch | SPC | Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris and 5 more | 9 hr |
| Oct 31, 4:46 AM CDT | Mesoscale Discussion | SPC | Brazoria, Chambers | 119 min |
| Oct 31, 7:35 AM CDT | Mesoscale Discussion | SPC | Chambers, Jefferson | 85 min |
Nearby
Mesoscale Discussions in Louisiana, 2015Mesoscale Discussions in Texas, 2015Every mesoscale discussion in 2015
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.