Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 2019

October 3, 201226 parishes in Louisiana; Adams County, Wilkinson County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Oct 3, 2012, 2:52 AM CDT for 26 parishes in Louisiana; Adams County, Wilkinson County, Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Oct 3, 2012, 2:52 AM CDT (07:52 UTC)
Expired
Oct 3, 2012, 5:15 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 28 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Wilkinson County, MS

The radar

The Lake Charles radar (KLCH), 104 km from the middle of the area, began a volume at 07:54 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 00:00Z, 7.9 hours before the alert went out and 103 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.

Skew-T log-pSkew-T log-p diagram, Lake Charles Mun, LA at 00:00Z on 2012-10-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 609 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lake Charles Mun, LA at 00:00Z on 2012-10-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
609 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
1745 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

082 
ACUS11 KWNS 030753
SWOMCD
SPC MCD 030752
LAZ000-MSZ000-031015-

MESOSCALE DISCUSSION 2019
NWS STORM PREDICTION CENTER NORMAN OK
0252 AM CDT WED OCT 03 2012

AREAS AFFECTED...SRN COASTAL LA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 030752Z - 031015Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A FEW STORMS WITH LARGE HAIL WILL THREATEN COASTAL SWRN LA
THIS MORNING...BUT A WATCH IS NOT EXPECTED.

DISCUSSION...ISOLATED THUNDERSTORMS HAVE FORMED JUST OFF THE SWRN LA
COAST...WITH A FEW STORMS ACROSS NERN LA AS WELL. THESE STORMS ARE
FORMING IN A WEAK TROUGH JUST ABOVE THE SURFACE...AND UNDER THE
UPPER VORT CENTER WITH COOL TEMPERATURES ALOFT AND A RELATIVELY
SHELTERED/MOIST RH PROFILE. THE STRONGEST CELLS WERE NEAR THE
COAST...WHERE HEATING FROM THE OCEAN IS LIKELY CONTRIBUTING.

SHEAR IS WEAK FOR ANY ORGANIZED SEVERE THREAT...BUT STEEP LAPSE
RATES ALOFT ALONG WITH A THE WEAKLY VEERING WINDS WITH HEIGHT WILL
CONTINUE TO FAVOR SLOW MOVING...MARGINALLY SEVERE HAIL THIS MORNING.

..JEWELL/THOMPSON.. 10/03/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...JAN...LIX...LCH...SHV...

LAT...LON   29679366 31739273 32079226 31979148 31459093 30939084
            30349082 29869104 29339135 29079167 28969227 28959264
            29089324 29159342 29679366

Nearby

Mesoscale Discussions in Louisiana, 2012Mesoscale Discussions in Mississippi, 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.