Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 10

January 9, 20129 parishes in Louisiana; 15 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jan 9, 2012, 9:33 AM CST for 9 parishes in Louisiana; 15 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jan 9, 2012, 9:33 AM CST (15:33 UTC)
Expired: Jan 9, 2012, 11:30 AM CST
In force: 117 min
Issued by: the Storm Prediction Center

All 24 counties

Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Jefferson Davis Parish, LA, Rapides Parish, LA, Vernon Parish, LA, Brazoria County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, San Jacinto County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 72 km from the middle of the area, began a volume at 15:35 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, 3.6 hours before the alert went out and 73 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: 610 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 546 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: 108 m²/s²
0-3 km storm-relative helicity: 169 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.4

Open this sounding in Storm Lab

The text

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

119 
ACUS11 KWNS 091533
SWOMCD
SPC MCD 091533 
LAZ000-TXZ000-091730-

MESOSCALE DISCUSSION 0010
NWS STORM PREDICTION CENTER NORMAN OK
0933 AM CST MON JAN 09 2012

AREAS AFFECTED...SE TX...SW LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 091533Z - 091730Z

AN ISOLATED THREAT FOR TORNADOES...LARGE HAIL AND WIND DAMAGE WILL
BE POSSIBLE ACROSS SE TX AND SW LA LATE THIS MORNING INTO EARLY THIS
AFTERNOON. ALTHOUGH THE SEVERE THREAT COULD BE MARGINAL...WW
ISSUANCE CAN NOT BE RULED OUT LATE THIS MORNING.

A LINE OF STRONG THUNDERSTORMS CURRENTLY LOCATED FROM JUST WEST OF
HOUSTON TX NEWD TO NEAR ALEXANDRIA LA WILL CONTINUE TO MOVE EWD LATE
THIS MORNING INTO A MOIST AIRMASS WHERE SFC DEWPOINTS ARE IN THE MID
TO UPPER 60S F. THE MOISTURE COMBINED WITH A STRONGLY SHEARED
ENVIRONMENT WILL BE FAVORABLE FOR ISOLATED SEVERE STORMS. THE LATEST
WSR-88 VWPS FROM SE TX AND SW LA SHOW STRONG DIRECTIONAL SHEAR IN
THE BOUNDARY LAYER RESULTING IN STORM RELATIVELY HELICITIES OF 300
TO 400 M2/S2. THIS WILL BE FAVORABLE FOR STORM ROTATION AND A COUPLE
TORNADOES MAY OCCUR ESPECIALLY IN A CORRIDOR FROM HOUSTON TX ENEWD
TO LAKE CHARLES LA WHERE THE COMBINATION OF INSTABILITY AND
LOW-LEVEL SHEAR APPEAR MOST FAVORABLE. MESOANALYSIS ALSO SHOWS STEEP
MID-LEVEL LAPSE RATES OF 7.0 TO 7.5 C/KM SUGGESTING AN ISOLATED
LARGE HAIL MAY ACCOMPANY THE MORE INTENSE CELLS EMBEDDED IN THE
LINE. WIND DAMAGE WILL ALSO BE POSSIBLE ESPECIALLY WITH BOWING
LINE-SEGMENTS.

..BROYLES.. 01/09/2012

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

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

LAT...LON   31179407 30609521 29959586 29539603 29089590 28939536
            29299454 29579380 29619282 29849236 30229216 30829210
            31349232 31429280 31179407

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 9, 5:59 AM CST	Mesoscale Discussion	SPC	Allen, Beauregard, Calcasieu, Vernon	3 hr
Jan 9, 1:29 AM CST	Mesoscale Discussion	SPC	Aransas, Austin, Bee, Brazoria, Calhoun, Chambers and 23 more	3 hr
Jan 9, 6:51 AM CST	Mesoscale Discussion	SPC	Andrews, Borden, Crane, Dawson, Ector, Garza and 8 more	5 hr

Nearby

Mesoscale Discussions in Texas, 2012 Mesoscale Discussions in Louisiana, 2012 Every 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.