Alert archive / Louisiana / Mesoscale Discussions in 2016

Mesoscale Discussion 10

January 9, 201621 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Jan 9, 2016, 2:52 AM CST for 21 parishes in Louisiana. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued: Jan 9, 2016, 2:52 AM CST (08:52 UTC)
Expired: Jan 9, 2016, 4:45 AM CST
In force: 113 min
Issued by: the Storm Prediction Center

All 21 counties

Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Pointe Coupee Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, West Baton Rouge Parish, LA

The radar

The Lake Charles radar (KLCH), 150 km from the middle of the area, began a volume at 08:52 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, 8.9 hours before the alert went out and 149 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: 1021 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 665 m above ground
0-6 km bulk shear: 71 kt
0-1 km storm-relative helicity: 201 m²/s²
0-3 km storm-relative helicity: 240 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 7.8

Open this sounding in Storm Lab

The text

As transmitted.

821 
ACUS11 KWNS 090853
SWOMCD
SPC MCD 090852 
LAZ000-091045-

MESOSCALE DISCUSSION 0010
NWS STORM PREDICTION CENTER NORMAN OK
0252 AM CST SAT JAN 09 2016

AREAS AFFECTED...SOUTHERN LA

CONCERNING...SEVERE THUNDERSTORM WATCH 2...

VALID 090852Z - 091045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 2 CONTINUES.

SUMMARY...ISOLATED HAIL AND/OR A STRONG WIND GUST REMAIN THE PRIMARY
SEVERE HAZARDS ACROSS SEVERE TSTM WATCH 2.  THE IMMEDIATE COASTAL
AREAS OF TERREBONNE PARISH HAS THE GREATEST POTENTIAL FOR A TORNADO
THREAT...THOUGH STORMS MAY NOT REACH THAT PART OF LA UNTIL CLOSER TO
12Z.  THIS LATTER THREAT WILL BE MONITORED NEAR AND EAST OF WW 2 FOR
ANY ADDITIONAL WW ISSUANCE OR AREAL/TEMPORAL EXTENSION OF WW 2.

DISCUSSION...AT 0830Z...MOSAIC RADAR IMAGERY INDICATED TWO PARALLEL
BANDS OF TSTMS EXTENDING FROM NNE-SSW ACROSS CENTRAL AND SOUTHERN LA
INTO THE NORTHWEST GULF OF MEXICO.  THE STORMS ACROSS LA AND WITHIN
A MAJORITY OF WW 2 WERE LIKELY ELEVATED GIVEN THEIR LOCATION NORTH
OF A WARM FRONT...WHICH AT 08Z REMAINED OFFSHORE EXTENDING FROM NEAR
KVBS /SABINE OIL PLATFORM/ TO THE EAST-SOUTHEAST...NORTH OF
KEIR...AND THEN JUST OFFSHORE SOUTHEAST TERREBONNE PARISH AND
THROUGH THE SOUTHEAST PORTION OF PLAQUEMINES PARISH.  THE STORMS
THAT HAVE POSED THE STRONGEST LOW-LEVEL ROTATION/TORNADO THREAT HAVE
REMAINED OFFSHORE...WITH THIS THREAT BEING THE GREATEST AS THEY
INTERACTED WITH THE WARM FRONT.  OTHERWISE...MUCAPE OF 200-400 J/KG
NORTH OF THE WARM FRONT AND EFFECTIVE BULK SHEAR AROUND 40 KT WILL
CONTINUE TO SUPPORT STORM ORGANIZATION AS STORMS CONTINUE TO FORM
WITHIN THE EXIT REGION OF A STRENGTHENING WLY MIDLEVEL JET.  HAIL
SHOULD BE THE PRIMARY THREAT...THOUGH LOCALLY STRONG WIND GUSTS WILL
BE POSSIBLE AS WELL WITH STORMS ACROSS SOUTHERN LA ENHANCED BY
MECHANICAL PROCESSES SUCH AS WATER LOADING.  

THE WESTERN BAND OF STORMS EXTENDING FROM EAST-CENTRAL LA TO JUST
EAST OF LCH AND INTO THE EXTREME NORTHWEST GULF OF MEXICO APPEARS TO
DELINEATE THE WESTERN EXTENT OF TSTM DEVELOPMENT WITHIN THIS
ENVIRONMENT.  VEERED 850-MB WINDS PER VWP DATA AT FORT POLK LA AND
HOUSTON TX SUPPORT THIS SCENARIO...AND SUGGEST PARISHES AND MARINE
ZONES WEST OF THIS BAND OF STORMS CAN BE CANCELLED FROM WW 2 WITH
ITS PASSAGE.

..PETERS.. 01/09/2016

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

ATTN...WFO...LIX...LCH...

LAT...LON   29489362 29969332 30769247 30829183 30669105 30249056
            29859025 29379002 28759009 28709068 28769116 28899187
            29139278 29329327 29489362

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 8, 6:31 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Caddo, Calcasieu, Cameron and 7 more	119 min
Jan 8, 9:52 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Beauregard, Calcasieu and 13 more	83 min
Jan 8, 10:44 PM CST	Severe Thunderstorm Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 19 more	7 hr
Jan 9, 5:28 AM CST	Mesoscale Discussion	SPC	Jefferson, Lafourche, Plaquemines	62 min

Nearby

Mesoscale Discussions in Louisiana, 2016 Every mesoscale discussion in 2016

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.