Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 2105

November 5, 20124 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Nov 5, 2012, 9:33 PM CST for 4 parishes in Louisiana. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Nov 5, 2012, 9:33 PM CST (03:33 UTC)
Expired
Nov 5, 2012, 10:30 PM CST
In force
57 min
Issued by
the Storm Prediction Center

Counties Jefferson Parish, LA, Lafourche Parish, LA, Plaquemines Parish, LA, Terrebonne Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 3.6 hours before the alert went out and 104 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, Slidell Radar S, LA at 00:00Z on 2012-11-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 356 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, Slidell Radar S, LA at 00:00Z on 2012-11-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 191 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
356 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
629 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
191 m²/s²
0-3 km storm-relative helicity
288 m²/s²
Significant tornado parameter
0.6
Supercell composite
5.6

Open this sounding in Storm Lab

The text

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

462 
ACUS11 KWNS 060333
SWOMCD
SPC MCD 060333 
LAZ000-060430-

MESOSCALE DISCUSSION 2105
NWS STORM PREDICTION CENTER NORMAN OK
0933 PM CST MON NOV 05 2012

AREAS AFFECTED...SERN LA

CONCERNING...SEVERE THUNDERSTORM WATCH 674...

VALID 060333Z - 060430Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 674
CONTINUES.

SUMMARY...THREAT FOR ISOLATED DAMAGING WIND AND HAIL WILL PERSIST AT
LEAST THROUGH 05Z ACROSS SERN LA. HOWEVER...IT APPEARS OVERALL
SEVERE THREAT IS BECOMING INCREASINGLY MARGINAL...AND MOST OF WW 674
WILL LIKELY NEED TO BE CANCELLED WELL BEFORE EXPIRATION TIME OF 07Z.

DISCUSSION...SCATTERED STORMS CONTINUE DEVELOPING ALONG PRE-FRONTAL
CONFLUENCE ZONE FROM THE NWRN GULF INTO EXTREME SERN LA. DEEP LAYER
WINDS ARE VEERING TO NWLY IN WAKE OF VORT MAX MOVING THROUGH LOWER
MS VALLEY...AND THIS SHOULD PROMOTE MOST OF ACTIVITY MOVING OFFSHORE
BY 05Z. OVERALL INTENSITY AND ORGANIZATION HAVE DECREASED LIKELY DUE
TO THE STABILIZING SFC LAYER. HOWEVER...40-50 KT EFFECTIVE SHEAR MAY
CONTINUE TO SUPPORT SOME ORGANIZATION WITH ONGOING STORMS.

..DIAL.. 11/06/2012

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

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

LAT...LON   29749050 29568966 29488902 29248897 29018940 29109092
            29469206 29589098 29749050

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 5, 7:35 PM CSTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Beauregard, Calcasieu and 27 more115 min

Nearby

Mesoscale Discussions in Louisiana, 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.