Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 2124
The Storm Prediction Center issued this mesoscale discussion at Nov 26, 2012, 5:08 PM CST for 29 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Nov 26, 2012, 5:08 PM CST (23:08 UTC)
- Expired
- Nov 26, 2012, 7:15 PM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 29 counties
Austin County, TX, Bastrop County, TX, Brazos County, TX, Burleson County, TX, Caldwell County, TX, Chambers County, TX, Colorado County, TX, Fayette County, TX, Fort Bend County, TX, Gonzales County, TX, Grimes County, TX, Hardin County, TX, Harris County, TX, Hays County, TX, Jefferson County, TX, Lavaca County, TX, Lee County, TX, Liberty County, TX, Madison County, TX, Milam County, TX, Montgomery County, TX, Robertson County, TX, San Jacinto County, TX, Travis County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Williamson County, TX
The radar
The Houston radar (KHGX), 113 km from the middle of the area, began a volume at 23:08 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, 11.1 hours before the alert went out and 265 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.
- Mixed-layer CAPE
- 1074 J/kg
- Mixed-layer CIN
- -9 J/kg
- Mixed-layer LCL
- 505 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 207 m²/s²
- 0-3 km storm-relative helicity
- 230 m²/s²
- Significant tornado parameter
- 0.8
- Supercell composite
- 5.5
The text
As transmitted, in the capitals the NWS used until 2016.
661
ACUS11 KWNS 262308
SWOMCD
SPC MCD 262308
LAZ000-TXZ000-270115-
MESOSCALE DISCUSSION 2124
NWS STORM PREDICTION CENTER NORMAN OK
0508 PM CST MON NOV 26 2012
AREAS AFFECTED...PORTIONS OF CNTRL/SERN TX
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 262308Z - 270115Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...ISOLATED SVR STORMS WITH SVR HAIL AND POSSIBLY SVR WINDS
MAY BE OF CONCERN LATE THIS AFTERNOON INTO THE EVENING...AND THE
ISSUANCE OF A WW IS POSSIBLE.
DISCUSSION...A COLD FRONT EXTENDS FROM THE ARKLATEX SWWD ACROSS THE
EDWARDS PLATEAU AND FARTHER W INTO THE TRANS-PECOS REGION. A FRONTAL
INFLECTION NOTED E OF JUNCTION TX APPEARS TO BE THE FOCUS FOR A
SMALL...BUT PERSISTENT...AREA OF CONVECTION. RECENT STORM
DEVELOPMENT IS NOTED IN CNTRL TX ALONG A PREFRONTAL TROUGH THAT
DELINEATES THE WRN EDGE OF RICHER GULF MOISTURE AND EXTENDS FROM
JUST NORTH OF SHREVEPORT LA TO NORTH OF AUSTIN. DURING THE NEXT FEW
HOURS...STORM COVERAGE WILL LIKELY INCREASE ALONG THE PREFRONTAL
TROUGH...WEST OF WHICH A DEEPER BOUNDARY LAYER/STEEP LOW-LEVEL LAPSE
RATE ENVIRONMENT IS PRESENT. FURTHERMORE...MID-LEVEL ASCENT
OVERSPREADING THE AREA...IN ASSOCIATION WITH A VORT MAX ABOUT TO
EMERGE OVER CNTRL/SRN TX PER WATER VAPOR IMAGERY...MAY ALSO LEAD TO
AN UPTICK IN CONVECTION. MLCAPE VALUES OF 1500-2000 J/KG NEAR/SE OF
THE PREFRONTAL TROUGH WILL SUPPORT INTENSE UPDRAFTS WITH SVR HAIL
POSSIBLE...THOUGH ONLY MODEST MID-LEVEL FLOW/DEEP SHEAR COULD LIMIT
THE THREAT. SVR WINDS MAY ALSO BE POSSIBLE...THOUGH THE UNDERCUTTING
NATURE OF THE COLD FRONT MAY MITIGATE THIS CONCERN.
..COHEN/DARROW.. 11/26/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LCH...HGX...FWD...EWX...
LAT...LON 29779389 29159550 29139676 29699819 30479838 30919740
31099640 30809520 30679395 29779389SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 26, 3:34 PM CST | Mesoscale Discussion | SPC | Anderson, Angelina, Camp, Cass, Cherokee, Gregg and 16 more | 86 min |
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.