Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 68

January 25, 201211 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jan 25, 2012, 10:09 AM CST for 11 counties in Texas. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued
Jan 25, 2012, 10:09 AM CST (16:09 UTC)
Expired
Jan 25, 2012, 11:45 AM CST
In force
96 min
Issued by
the Storm Prediction Center

Counties Brazoria County, TX, Chambers County, TX, Fort Bend County, TX, Harris County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, Polk County, TX, San Jacinto County, TX, Waller County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 62 km from the middle of the area, began a volume at 16:11 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, 4.2 hours before the alert went out and 207 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 2012-01-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 28 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 2012-01-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 241 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
28 J/kg
Mixed-layer CIN
-201 J/kg
Mixed-layer LCL
576 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
241 m²/s²
0-3 km storm-relative helicity
341 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.6

Open this sounding in Storm Lab

The text

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

400 
ACUS11 KWNS 251610
SWOMCD
SPC MCD 251609
TXZ000-251745-

MESOSCALE DISCUSSION 0068
NWS STORM PREDICTION CENTER NORMAN OK
1009 AM CST WED JAN 25 2012

AREAS AFFECTED...SERN TX

CONCERNING...TORNADO WATCH 14...

VALID 251609Z - 251745Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 14 CONTINUES.

A LINE OF STORMS WILL CONTINUE TO SLOWLY MOVE AND PROPAGATE EWD
ACROSS THE REMAINDER OF SERN TEXAS OVER THE NEXT FEW HOURS. AT THE
CURRENT RATE OF MOTION...IT MAY TAKE AROUND 2-3 HOURS TO CLEAR THE
REMAINING PORTIONS OF TORNADO WATCH 14. THEREFORE...EITHER A LOCAL
EXTENSION OR PERHAPS AN ADDITIONAL/SMALL WATCH MAY BE NECESSARY.

ALTHOUGH STORM MODE IS QUASI-LINEAR...SHEAR PROFILES REMAIN QUITE
FAVORABLE FOR SUSTAINED LONG LIVED CONVECTIVE SYSTEMS WITH THE
POSSIBILITY OF ROTATION AND BRIEF TORNADOES.

..JEWELL.. 01/25/2012

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

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

LAT...LON   29499455 28309629 29239654 30219595 30749535 31419496
            31009458 29499455

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 24, 7:13 PM CSTMesoscale DiscussionSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Caldwell and 23 more92 min
Jan 24, 10:05 PM CSTTornado WatchSPCAtascosa, Bandera, Bastrop, Bee, Bexar, Blanco and 33 more5 hr
Jan 24, 11:34 PM CSTMesoscale DiscussionSPCAtascosa, Bandera, Bastrop, Bee, Bexar, Blanco and 38 more56 min
Jan 25, 2:12 AM CSTMesoscale DiscussionSPCAtascosa, Austin, Bandera, Bastrop, Bee, Bell and 56 more2 hr
Jan 25, 3:17 AM CSTTornado WatchSPCAnderson, Aransas, Atascosa, Austin, Bastrop, Bee and 67 more11 hr
Jan 25, 7:13 AM CSTMesoscale DiscussionSPCAnderson, Angelina, Aransas, Austin, Bee, Brazoria and 40 more2 hr
Jan 25, 7:56 AM CSTTornado WatchSPCAngelina, Cherokee, Hardin, Jasper, Jefferson, Nacogdoches and 8 more7 hr
Jan 25, 11:24 AM CSTMesoscale DiscussionSPCBrazoria, Chambers, Galveston, Hardin, Harrison, Jasper and 10 more2 hr
Jan 25, 2:08 PM CSTTornado WatchSPCJefferson, Orange7 hr

Nearby

Mesoscale Discussions in Texas, 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; radar from the NEXRAD Level II archive.