Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 64

January 24, 201229 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jan 24, 2012, 7:13 PM CST for 29 counties in Texas. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Jan 24, 2012, 7:13 PM CST (01:13 UTC)
Expired
Jan 24, 2012, 8:45 PM CST
In force
92 min
Issued by
the Storm Prediction Center
All 29 counties

Atascosa County, TX, Bandera County, TX, Bastrop County, TX, Bexar County, TX, Blanco County, TX, Caldwell County, TX, Comal County, TX, Dimmit County, TX, Edwards County, TX, Frio County, TX, Gillespie County, TX, Guadalupe County, TX, Hays County, TX, Kendall County, TX, Kerr County, TX, Kimble County, TX, Kinney County, TX, Llano County, TX, Mason County, TX, Maverick County, TX, Medina County, TX, Menard County, TX, Real County, TX, Sutton County, TX, Travis County, TX, Uvalde County, TX, Val Verde County, TX, Wilson County, TX, Zavala County, TX

The radar

The Laughlin AFB radar (KDFX), 120 km from the middle of the area, began a volume at 01:16 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

Del Rio, TX (KDRT), launched 00:00Z, 1.2 hours before the alert went out and 160 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, Del Rio, TX at 00:00Z on 2012-01-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 619 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, Del Rio, TX at 00:00Z on 2012-01-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 253 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
619 J/kg
Mixed-layer CIN
-174 J/kg
Mixed-layer LCL
573 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
253 m²/s²
0-3 km storm-relative helicity
168 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.8

Open this sounding in Storm Lab

The text

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

475 
ACUS11 KWNS 250114
SWOMCD
SPC MCD 250113
TXZ000-250245-

MESOSCALE DISCUSSION 0064
NWS STORM PREDICTION CENTER NORMAN OK
0713 PM CST TUE JAN 24 2012

AREAS AFFECTED...EDWARDS PLATEAU...HILL COUNTRY

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 250113Z - 250245Z

THREAT FOR LARGE HAIL...ISOLATED DAMAGING WINDS...AND PERHAPS A
TORNADO WILL INCREASE AS TSTM COVERAGE GROWS LATER THIS EVENING.
ALTHOUGH UNCERTAINTY EXISTS OVER THE TYPE OF WW...THE PROBABILITY OF
ISSUANCE BY 03Z IS 60 PERCENT.

01Z SURFACE ANALYSIS PLACED A SERIES OF WEAK CYCLONES ACROSS THE
PERMIAN BASIN/BIG BEND...AND ALONG THE RIO GRANDE BETWEEN DRT AND
LRD. PRIMARY SURFACE WARM FRONT HAS BECOME QUASI-STATIONARY S OF THE
HILL COUNTRY WITH A RELATIVELY RICH WARM/MOIST AIR MASS ACROSS MUCH
OF S-CNTRL TX. FARTHER NW...MORE MARGINAL SURFACE-BASED INSTABILITY
EXISTS WITH A STRONG CAPPING INVERSION CENTERED NEAR 800 MB IN THE
00Z DRT RAOB. THIS CAPPING INVERSION WILL BE GRADUALLY REMOVED AS
BAND OF FORCED ASCENT /NOW CROSSING THE BIG BEND/ OVERSPREADS THE
MODIFIED WARM SECTOR OVER THE EDWARDS PLATEAU. STEEP MID-LEVEL LAPSE
RATES AND EFFECTIVE SHEAR OF 40-50 KT WILL PROVE FAVORABLE FOR LARGE
HAIL. WHILE A WEAKNESS IN THE LOW-LEVEL HODOGRAPH MAY PERSIST
BETWEEN 800-700 MB...VEERING MAY BE SUFFICIENT FOR A MARGINAL
TORNADO THREAT. HOWEVER...STRONGER LOW-LEVEL SLYS SHOULD REMAIN
CONFINED E OF THE I-35 CORRIDOR. IN ADDITION...CONVECTION-ALLOWING
MODELS LARGELY SUGGEST TSTMS WOULD QUICKLY TRANSITION INTO A CLUSTER
MODE WITH PROPAGATION TOWARDS THE NE INTO A LESS UNSTABLE AIR MASS.

..GRAMS.. 01/25/2012

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

ATTN...WFO...CRP...EWX...SJT...

LAT...LON   29730142 30260125 30810077 30960033 31049970 30999913
            30719865 30639781 30529732 30279702 29789710 29389761
            28699862 28439939 28380027 29250085 29730142

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
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, 10:09 AM CSTMesoscale DiscussionSPCBrazoria, Chambers, Fort Bend, Harris, Liberty, Matagorda and 5 more96 min
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.