Alert archive / Louisiana / Mesoscale Discussions in 2016

Mesoscale Discussion 32

January 21, 201614 parishes in Louisiana; 9 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jan 21, 2016, 4:40 AM CST for 14 parishes in Louisiana; 9 counties in Texas. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: Jan 21, 2016, 4:40 AM CST (10:40 UTC)
Expired: Jan 21, 2016, 6:15 AM CST
In force: 95 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 23 counties

Allen Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Cherokee County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX

The radar

The Shreveport radar (KSHV), 76 km from the middle of the area, began a volume at 10:41 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

Shreveport, LA (KBAD), launched 00:00Z, 10.7 hours before the alert went out and 80 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1116 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 119 m²/s²
0-3 km storm-relative helicity: 169 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

157 
ACUS11 KWNS 211041
SWOMCD
SPC MCD 211040 
LAZ000-TXZ000-211215-

MESOSCALE DISCUSSION 0032
NWS STORM PREDICTION CENTER NORMAN OK
0440 AM CST THU JAN 21 2016

AREAS AFFECTED...PORTIONS OF FAR EASTERN TX INTO CENTRAL LA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 211040Z - 211215Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORMS WILL CONTINUE TO TRACK NORTHEAST ACROSS
PORTIONS OF EASTERN TX INTO CENTRAL LA EARLY THIS MORNING. A FEW
STRONGER STORMS MAY PRODUCE MARGINALLY SEVERE HAIL. A WATCH IS NOT
EXPECTED AT THIS TIME.

DISCUSSION...ELEVATED THUNDERSTORMS ARE DEVELOPING EARLY THIS
MORNING ACROSS EAST TX INTO CENTRAL LA IN WEAK WARM ADVECTION REGIME
ON THE FRINGES OF STRONGER DEEP LAYER SHEAR NEAR THE UPPER TX AND
SOUTHWESTERN LA COAST. INSTABILITY IS FAIRLY WEAK ACROSS THE REGION
/MUCAPE NEAR 500 J PER KG/...BUT STEEP MIDLEVEL LAPSE RATES HAVE
ADVECTED EASTWARD ACROSS TX/LA AHEAD OF AN UPPER SHORTWAVE TROUGH.
THESE STEEP LAPSE RATES AND EFFECTIVE SHEAR FROM 30-40 KT WILL AID
IN UPDRAFT ROTATION AND AT LEAST SMALL HAIL PRODUCTION...WITH
ISOLATED INSTANCES OF MARGINALLY SEVERE HAIL. MODEST DEEP LAYER
FORCING FOR ASCENT COUPLED WITH LIMITED INSTABILITY SHOULD LIMIT
COVERAGE/LONGEVITY OF STRONGER UPDRAFTS. AS SUCH...A WATCH IS NOT
EXPECTED AT THIS TIME.

..LEITMAN/DIAL.. 01/21/2016

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

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

LAT...LON   32179543 32389500 32589412 32629325 32539263 32429244
            31919215 31239216 30699258 30579322 30789409 31049485
            31479533 31949551 32179543

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 21, 10:59 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Evangeline and 7 more	2 hr
Jan 21, 11:48 AM CST	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 12 more	5 hr
Jan 21, 1:44 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 29 more	2 hr
Jan 21, 2:14 PM CST	Tornado Watch	SPC	Ascension, Assumption, Catahoula, Concordia, East Baton Rouge, East Feliciana and 23 more	6 hr
Jan 21, 4:57 PM CST	Mesoscale Discussion	SPC	East Feliciana, Saint Helena	63 min

Nearby

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