Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 979

June 18, 20164 parishes in Louisiana; 19 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2016, 3:20 PM CDT for 4 parishes in Louisiana; 19 counties in Texas. It was in force for 25 min.

The area

The outline as issued.

The facts

Issued
Jun 18, 2016, 3:20 PM CDT (20:20 UTC)
Expired
Jun 18, 2016, 3:45 PM CDT
In force
25 min
Issued by
the Storm Prediction Center
All 23 counties

Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Jefferson Davis Parish, LA, Angelina County, TX, Cherokee County, TX, Gregg County, TX, Hardin County, TX, Harrison County, TX, Jasper County, TX, Jefferson County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Tyler County, TX, Upshur County, TX

The radar

The Ft Polk radar (KPOE), 99 km from the middle of the area, began a volume at 20:24 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, 8.3 hours before the alert went out and 130 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 2016-06-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2313 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 2016-06-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -57 square meters per square second.1939Sfc1 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
2313 J/kg
Mixed-layer CIN
-44 J/kg
Mixed-layer LCL
781 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-57 m²/s²
0-3 km storm-relative helicity
11 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

784 
ACUS11 KWNS 182021
SWOMCD
SPC MCD 182020 
LAZ000-TXZ000-182045-

MESOSCALE DISCUSSION 0979
NWS STORM PREDICTION CENTER NORMAN OK
0320 PM CDT SAT JUN 18 2016

AREAS AFFECTED...SWRN LA / E TX

CONCERNING...SEVERE THUNDERSTORM WATCH 270...

VALID 182020Z - 182045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 270
CONTINUES.

SUMMARY...THE ISOLATED THREAT FOR DAMAGING STRAIGHT-LINE WINDS WILL
CONTINUE OWING TO GUSTS GENERALLY IN THE 45-60 MPH RANGE.

DISCUSSION...RADAR MOSAIC SHOWS A WELL-DEVELOPED ARCING GUST
FRONT/OUTFLOW FROM A WEAKLY ORGANIZED MCS MOVING WWD ACROSS THE
SABINE RIVER VALLEY.  A 42-KT GUST WAS OBSERVED AT KDTN IN NWRN LA
AROUND 19Z.  THE BOUNDARY LAYER DOWNSTREAM OVER E TX IS STRONGLY
UNSTABLE /2500 J PER KG MLCAPE/ PER THE 18Z LCH RAOB WITH TEMPS IN
THE LOWER 90S AND DEWPOINTS IN THE LOWER 70S.  THE 18Z LCH RAOB
FEATURED A LOWEST 100 MB MEAN MIXING RATIO AROUND 17 G/KG AND PW OF
1.7 INCHES.  THIS MOIST AIRMASS IS CO-LOCATED WITH RELATIVELY STEEP
0-3 KM LAPSE RATES /8-9 DEG C PER KM/ AND WILL PROBABLY SUPPORT
POCKETS OF STRONG TO LOW-END SEVERE GUSTS CAPABLE OF LOCALIZED WIND
DAMAGE FOR THE NEXT SEVERAL HOURS.

..SMITH.. 06/18/2016

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

ATTN...WFO...LCH...SHV...HGX...FWD...

LAT...LON   29719428 31689550 32749524 32769396 31839411 30939349
            30509253 29699273 29719428

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 18, 11:31 AM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, De Soto and 11 more89 min
Jun 18, 1:16 PM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Beauregard, Bossier, Caddo, Calcasieu and 11 more6 hr
Jun 18, 3:14 PM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Foard, Hardeman, Montague and 2 more2 hr

Nearby

Mesoscale Discussions in Texas, 2016Mesoscale Discussions in Louisiana, 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.