Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 2103

November 5, 20125 parishes in Louisiana; 24 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Nov 5, 2012, 5:25 PM CST for 5 parishes in Louisiana; 24 counties in Texas. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Nov 5, 2012, 5:25 PM CST (23:25 UTC)
Expired
Nov 5, 2012, 7:00 PM CST
In force
95 min
Issued by
the Storm Prediction Center
All 29 counties

Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Jefferson Davis Parish, LA, Austin County, TX, Bastrop County, TX, Brazoria County, TX, Caldwell County, TX, Chambers County, TX, Colorado County, TX, DeWitt County, TX, Fayette County, TX, Fort Bend County, TX, Galveston County, TX, Gonzales County, TX, Hardin County, TX, Harris County, TX, Jackson County, TX, Jefferson County, TX, Lavaca County, TX, Lee County, TX, Liberty County, TX, Montgomery County, TX, Orange County, TX, Victoria County, TX, Waller County, TX, Washington County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 38 km from the middle of the area, began a volume at 23:27 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, 11.4 hours before the alert went out and 157 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 12:00Z on 2012-11-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 126 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 12:00Z on 2012-11-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 80 square meters per square second.19395878Sfc1 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
126 J/kg
Mixed-layer CIN
-139 J/kg
Mixed-layer LCL
665 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
80 m²/s²
0-3 km storm-relative helicity
112 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

458 
ACUS11 KWNS 052325
SWOMCD
SPC MCD 052325 
LAZ000-TXZ000-060100-

MESOSCALE DISCUSSION 2103
NWS STORM PREDICTION CENTER NORMAN OK
0525 PM CST MON NOV 05 2012

AREAS AFFECTED...PORTIONS OF SERN TX AND SWRN LA

CONCERNING...SEVERE THUNDERSTORM WATCH 673...

VALID 052325Z - 060100Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 673
CONTINUES.

SUMMARY...THE THREAT FOR STORMS WITH SVR WINDS/HAIL CONTINUES ACROSS
WW 673...WITH THE GREATEST THREAT FOR SVR STORMS LYING WITHIN 60-75
MILES OF THE UPPER TX COAST TO THE SW LA COAST.

DISCUSSION...LATEST SFC MESOANALYSIS DEPICTS A DIFFUSE FRONT
TRAILING WSW OF A MESOLOW LOCATED 30 SSE ALEXANDRIA TO 50 WNW
BEAUMONT TX WITH A REMNANT TROUGH AXIS EXTENDING FARTHER WEST INTO
S-CNTRL TX. THE STRONGEST SFC CONVERGENCE ALONG THESE FEATURES IS
APPARENT ACROSS CNTRL AND ERN PARTS OF THE WW AREA...WHERE
ADDITIONAL STORM INITIATION WOULD BE MOST LIKELY. STORMS COULD ALSO
EVOLVE FROM THE LOW-TO-MID-LEVEL CUMULUS DECK OVER E-CNTRL TX THAT
LEADS A REINFORCING COLD FRONT. THE GREATEST POTENTIAL FOR SVR
STORMS WILL EXIST WITHIN 60-75 MILES OF THE UPPER TX COAST TO THE SW
LA COAST...WHERE RELATIVELY HIGHER DEWPOINTS IN THE LOWER/MIDDLE 60S
ARE SUPPORTING MLCAPE VALUES OF 1000-1500 J/KG. IN THIS AREA...THE
PRESENCE OF 45-60 KT OF EFFECTIVE BULK SHEAR WILL SUPPORT ORGANIZED
CONVECTIVE STRUCTURES CAPABLE OF PRODUCING SVR WINDS/HAIL.
ELSEWHERE...LIMITED CONVECTIVE COVERAGE IS ANTICIPATED.

..COHEN.. 11/05/2012

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

ATTN...WFO...LCH...HGX...CRP...EWX...

LAT...LON   29169276 28729768 30309768 30739274 29169276

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 5, 1:19 PM CSTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 21 more86 min
Nov 5, 2:08 PM CSTSevere Thunderstorm WatchSPCBeauregard, Calcasieu, Cameron7 hr
Nov 5, 4:43 PM CSTMesoscale DiscussionSPCAcadia, Ascension, Assumption, East Baton Rouge, East Feliciana, Evangeline and 22 more92 min
Nov 5, 5:29 PM CSTSevere Thunderstorm WatchSPCAcadia, Allen, Ascension, Assumption, East Baton Rouge, East Feliciana and 26 more6 hr

Nearby

Mesoscale Discussions in Texas, 2012Mesoscale 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; radar from the NEXRAD Level II archive.