Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 71

January 25, 201230 parishes in Louisiana; 23 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jan 25, 2012, 4:49 PM CST for 30 parishes in Louisiana; 23 counties in Mississippi. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Jan 25, 2012, 4:49 PM CST (22:49 UTC)
Expired
Jan 25, 2012, 6:15 PM CST
In force
86 min
Issued by
the Storm Prediction Center
All 53 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Avoyelles Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hinds County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lawrence County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Pike County, MS, Rankin County, MS, Sharkey County, MS, Simpson County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS, Yazoo County, MS

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 10.8 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-pSkew-T log-p diagram, Jackson, MS at 12:00Z on 2012-01-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Jackson, MS at 12:00Z on 2012-01-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 245 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
737 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
245 m²/s²
0-3 km storm-relative helicity
348 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

305 
ACUS11 KWNS 252250
SWOMCD
SPC MCD 252249
MSZ000-LAZ000-ARZ000-260015-

MESOSCALE DISCUSSION 0071
NWS STORM PREDICTION CENTER NORMAN OK
0449 PM CST WED JAN 25 2012

AREAS AFFECTED...MUCH OF LA/FAR SOUTHERN AR TO CENTRAL/SOUTHERN MS

CONCERNING...TORNADO WATCH 16...

VALID 252249Z - 260015Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 16 CONTINUES.

TORNADO WATCH 16 CONTINUES UNTIL 03Z...WITH CONTINUED POTENTIAL FOR
ISOLATED TORNADOES AND WIND DAMAGE ALONG WITH LOCALLY HEAVY
RAINFALL. MONITORING FOR AN ADDITIONAL TORNADO WATCH FOR PORTIONS OF
CENTRAL/SOUTHERN MS.

A WELL-ORGANIZED SQUALL LINE CONTINUES TO STEADILY PROGRESS EASTWARD
ACROSS NORTHEAST/CENTRAL/SOUTHWEST PORTIONS OF LA AS OF
2245Z....WITH PRECEDING WARM SECTOR DEVELOPMENT ACROSS NORTHEAST
LA/FAR WESTERN MS. STRONG/DEEP SOUTHERLY FLOW WILL CONTINUE TO YIELD
A QUASI-LINEAR CONVECTIVE MODE WITH EMBEDDED BOWING
STRUCTURES/MESO-VORTICES AMID RELATIVELY STRONG WINDS/SRH WITHIN THE
LOWEST FEW KM. ACCORDINGLY...WIND DAMAGE AND ISOLATED TORNADOES WILL
REMAIN POSSIBLE INTO THIS EVENING...AND SUCH A THREAT MAY CONTINUE
INTO PORTIONS OF CENTRAL/EVENTUALLY SOUTHERN MS TO THE EAST OF
CURRENT WW 16. ADDITIONALLY...A MERIDIONAL-TYPE PATTERN AND
QLCS-PARALLEL DEEP SOUTHERLY FLOW...IN CONJUNCTION WITH AMPLE
MOISTURE...WILL ALSO CONTINUE TO FAVOR LOCALLY HEAVY RAINFALL.

..GUYER.. 01/25/2012

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

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

LAT...LON   32289168 32949151 33319097 32948981 30378968 29339359
            30899293 31729189 32289168

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 25, 7:56 AM CSTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Bossier and 24 more7 hr
Jan 25, 11:24 AM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Bossier and 25 more2 hr
Jan 25, 1:41 PM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 13 more94 min
Jan 25, 2:08 PM CSTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 41 more7 hr

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.