Alert archive / Louisiana / Mesoscale Discussions in 2021
Mesoscale Discussion 978
The Storm Prediction Center issued this mesoscale discussion at Jun 15, 2021, 1:26 PM CDT for 17 parishes in Louisiana; 8 counties in Texas. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 15, 2021, 1:26 PM CDT (18:26 UTC)
- Expired
- Jun 15, 2021, 4:00 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
All 25 counties
Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, West Baton Rouge Parish, LA, Chambers County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Newton County, TX, Orange County, TX, Tyler County, TX
The radar
The Lake Charles radar (KLCH), 41 km from the middle of the area, began a volume at 18:31 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, 6.4 hours before the alert went out and 39 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
- 2560 J/kg
- Mixed-layer CIN
- -30 J/kg
- Mixed-layer LCL
- 884 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 22 m²/s²
- 0-3 km storm-relative helicity
- 6 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
593
ACUS11 KWNS 151826
SWOMCD
SPC MCD 151826
LAZ000-TXZ000-152100-
Mesoscale Discussion 0978
NWS Storm Prediction Center Norman OK
0126 PM CDT Tue Jun 15 2021
Areas affected...southeast Texas through southern Louisiana
Concerning...Severe potential...Watch unlikely
Valid 151826Z - 152100Z
Probability of Watch Issuance...5 percent
SUMMARY...Storms may become capable of producing isolated downburst
winds from mid afternoon through early evening.
DISCUSSION...Visible satellite imagery continues to show an increase
in towering cumulus development from southeast TX into southern LA
with a few showers also indicated on radar. The boundary layer in
this region is very moist with low to mid 70s F dewpoints supporting
2500-3500 J/kg MLCAPE as temperatures climb through the upper 80s to
low 90s F. Thunderstorms will gradually increase in coverage this
afternoon within the pre-frontal warm sector and along sea-breeze
boundaries. Very weak vertical shear will promote pulse and
multicell storms. However, the thermodynamic environment (as
indicated by the 18Z LIX RAOB) appears favorable for a few instances
of downburst winds with the stronger storms.
..Dial/Grams.. 06/15/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LIX...LCH...SHV...HGX...
LAT...LON 29659048 29969298 29829425 29419520 30079547 31049447
30649209 30398975 29659048Nearby
Mesoscale Discussions in Louisiana, 2021Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021
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.