Alert archive / Louisiana / Mesoscale Discussions in 2016

Mesoscale Discussion 35

January 21, 201635 parishes in Louisiana; 19 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jan 21, 2016, 1:44 PM CST for 35 parishes in Louisiana; 19 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jan 21, 2016, 1:44 PM CST (19:44 UTC)
Expired
Jan 21, 2016, 3:45 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
All 54 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Vernon Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Wilkinson County, MS

The radar

The Ft Polk radar (KPOE), 128 km from the middle of the area, began a volume at 19:43 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 7.7 hours before the alert went out and 179 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 2016-01-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1051 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 2016-01-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 192 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
1051 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
548 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
192 m²/s²
0-3 km storm-relative helicity
215 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.2

Open this sounding in Storm Lab

The text

As transmitted.

755 
ACUS11 KWNS 211945
SWOMCD
SPC MCD 211944 
MSZ000-LAZ000-212145-

MESOSCALE DISCUSSION 0035
NWS STORM PREDICTION CENTER NORMAN OK
0144 PM CST THU JAN 21 2016

AREAS AFFECTED...LA...SW-SCNTRL MS

CONCERNING...TORNADO WATCH 5...

VALID 211944Z - 212145Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 5 CONTINUES.

SUMMARY...A SEVERE THREAT WILL GRADUALLY SPREAD EWD ACROSS ERN LA
AND INTO SCNTRL MS THIS AFTERNOON. TORNADOES...ISOLATED LARGE HAIL
AND WIND DAMAGE WILL BE POSSIBLE WITH THE MORE INTENSE STORMS. WW
ISSUANCE WILL LIKELY BE NEEDED TO THE EAST OF WW 5.

DISCUSSION...THE LATEST RADAR TRENDS SHOW A CLUSTER OF ROTATING
THUNDERSTORMS ALONG A PRE-FRONTAL CONFLUENCE ZONE IN WRN LA. STRONG
THUNDERSTORMS ARE ALSO ONGOING ALONG A COLD FRONT IN FAR ERN TX.
THIS ACTIVITY IS LOCATED VERY NEAR TO A SFC LOW WHICH WILL CONTINUE
TO DEEPEN AND TRACK EWD ACROSS LA LATE THIS AFTERNOON. SFC WINDS IN
THE NERN QUADRANT OF THE SFC LOW ARE BACKED TO THE EAST AND
SOUTHEAST WHICH IS ENHANCING LOW-LEVEL SHEAR PROFILES. ALTHOUGH SFC
WINDS ARE STARTING TO VEER TO THE SOUTH IN WRN LA...THE WSR-88D VWP
AT POE WITHIN THE LAST HOUR HAS HAD 0-3 KM STORM RELATIVE HELICITIES
NEAR 300 M2/S2. THIS SHOULD BE REPRESENTATIVE OF THE LOW-LEVEL SHEAR
FURTHER TO THE EAST NEAR THE MS RIVER WHERE INSTABILITY HAS MARKEDLY
INCREASED OVER THE NEXT 1 TO 2 HOURS. THIS ENVIRONMENT SHOULD
CONTINUE TO SUPPORT ROTATING STORMS CAPABLE OF PRODUCING TORNADOES
AND WIND DAMAGE. AN ISOLATED LARGE HAIL THREAT WILL ALSO EXIST WITH
THE STRONGER UPDRAFTS.

..BROYLES/THOMPSON.. 01/21/2016

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

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

LAT...LON   32109281 31089323 30389343 30119328 29979268 29849144
            29988969 31208915 32068943 32299008 32109281

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 21, 4:40 AM CSTMesoscale DiscussionSPCAllen, Beauregard, Bienville, Caddo, De Soto, Grant and 8 more95 min
Jan 21, 10:59 AM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Evangeline and 7 more2 hr
Jan 21, 11:48 AM CSTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 12 more5 hr
Jan 21, 2:14 PM CSTTornado WatchSPCAscension, Assumption, Catahoula, Concordia, East Baton Rouge, East Feliciana and 23 more6 hr
Jan 21, 4:57 PM CSTMesoscale DiscussionSPCEast Feliciana, Saint Helena63 min
Jan 21, 11:03 AM CSTMesoscale DiscussionSPCAttala, Hinds, Leake, Madison, Warren, Yazoo87 min
Jan 21, 5:29 PM CSTMesoscale DiscussionSPCClarke, George, Greene, Harrison, Jackson, Lauderdale and 3 more2 hr

Nearby

Mesoscale Discussions in Louisiana, 2016Mesoscale Discussions in Mississippi, 2016Every 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.