Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 2244

December 28, 2012Calcasieu Parish, Cameron Parish, Louisiana; Jefferson County, Orange County, Texas

The Storm Prediction Center issued this mesoscale discussion at Dec 28, 2012, 6:31 AM CST for Calcasieu Parish, Cameron Parish, Louisiana; Jefferson County, Orange County, Texas. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Dec 28, 2012, 6:31 AM CST (12:31 UTC)
Expired: Dec 28, 2012, 8:00 AM CST
In force: 89 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Calcasieu Parish, LA, Cameron Parish, LA, Jefferson County, TX, Orange County, TX

The radar

The Lake Charles radar (KLCH), 58 km from the middle of the area, began a volume at 12:31 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, 0.5 hours before the alert went out and 59 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 133 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 443 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 633 m²/s²
0-3 km storm-relative helicity: 834 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.6

Open this sounding in Storm Lab

The text

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

920 
ACUS11 KWNS 281231
SWOMCD
SPC MCD 281231 
LAZ000-TXZ000-281400-

MESOSCALE DISCUSSION 2244
NWS STORM PREDICTION CENTER NORMAN OK
0631 AM CST FRI DEC 28 2012

AREAS AFFECTED...FAR SERN TX...FAR SWRN LA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 281231Z - 281400Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A MARGINAL AND SPATIALLY LIMITED THREAT FOR A TORNADO
EXISTS THIS MORNING NEAR THE MOUTH OF THE SABINE RIVER.

DISCUSSION...12Z SURFACE ANALYSIS PLACED A 1007 MB CYCLONE JUST NW
OF BPT WITH A WARM FRONT ARCING E/SEWD NEAR THE LA COAST.
WEAK/TRANSIENT AREAS OF LOW-LEVEL ROTATION HAVE BEEN NOTED IN
SHOWERS WITHIN THE WARM FRONTAL ZONE AND A NNE/SSW-ORIENTED BAND OF
SHOWERS/EMBEDDED TSTMS...SUPPORTED BY 0-1 KM SHEAR AROUND 30-35 KT
PER INTERPOLATED VWP DATA/12Z LCH RAOB. MIDDLE 60S SURFACE DEW
POINTS ARE NEEDED PER MODIFIED 12Z LCH RAOB TO ELICIT EVEN MODEST
MLCAPE OF AROUND 250 J/KG...GIVEN THE PRESENCE OF POOR TROPOSPHERIC
LAPSE RATES. THIS SHOULD LARGELY DETER TORNADO POTENTIAL FROM BEING
REALIZED...BUT A BRIEF TORNADO CANNOT BE COMPLETELY RULED OUT.

..GRAMS/EDWARDS.. 12/28/2012

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

ATTN...WFO...LCH...HGX...

LAT...LON   30409438 30509394 30329346 30109308 29709300 29669376
            29549451 30409438

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 28, 9:41 AM CST	Mesoscale Discussion	SPC	Acadia, Calcasieu, Cameron, Iberia, Jefferson Davis, Lafayette and 3 more	94 min
Dec 28, 3:51 PM CST	Mesoscale Discussion	SPC	Jefferson, Lafourche, Plaquemines, Terrebonne	84 min

Nearby

Mesoscale Discussions in Louisiana, 2012 Mesoscale Discussions in Texas, 2012 Every 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.