Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 238
The Storm Prediction Center issued this mesoscale discussion at Mar 8, 2012, 7:32 PM CST for 39 counties in Texas. It was in force for 88 min.
The area
The outline as issued.
The facts
- Issued
- Mar 8, 2012, 7:32 PM CST (01:32 UTC)
- Expired
- Mar 8, 2012, 9:00 PM CST
- In force
- 88 min
- Issued by
- the Storm Prediction Center
All 39 counties
Atascosa County, TX, Austin County, TX, Bandera County, TX, Bastrop County, TX, Bee County, TX, Bexar County, TX, Caldwell County, TX, Colorado County, TX, Comal County, TX, DeWitt County, TX, Dimmit County, TX, Duval County, TX, Fayette County, TX, Fort Bend County, TX, Frio County, TX, Goliad County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Jackson County, TX, Jim Wells County, TX, Karnes County, TX, Kendall County, TX, La Salle County, TX, Lavaca County, TX, Lee County, TX, Live Oak County, TX, McMullen County, TX, Medina County, TX, Refugio County, TX, San Patricio County, TX, Travis County, TX, Uvalde County, TX, Victoria County, TX, Washington County, TX, Webb County, TX, Wharton County, TX, Wilson County, TX, Zavala County, TX
The radar
The Austin/San Antonio radar (KEWX), 87 km from the middle of the area, began a volume at 01:31 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
Corpus Christi, TX (KCRP), launched 00:00Z, 1.5 hours before the alert went out and 153 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
- 1750 J/kg
- Mixed-layer CIN
- -74 J/kg
- Mixed-layer LCL
- 661 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 137 m²/s²
- 0-3 km storm-relative helicity
- 179 m²/s²
- Significant tornado parameter
- 0.8
- Supercell composite
- 5.3
The text
As transmitted, in the capitals the NWS used until 2016.
207
ACUS11 KWNS 090132
SWOMCD
SPC MCD 090132
TXZ000-090300-
MESOSCALE DISCUSSION 0238
NWS STORM PREDICTION CENTER NORMAN OK
0732 PM CST THU MAR 08 2012
AREAS AFFECTED...PORTIONS OF THE LWR RIO GRANDE VALLEY/SRN TX
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 090132Z - 090300Z
THUNDERSTORMS ARE EXPECTED TO DEVELOP AND INCREASE IN COVERAGE
TONIGHT OVER PORTIONS OF THE LWR RIO GRANDE VALLEY/SRN TX. THOUGH
STORMS MAY POSE A THREAT FOR LARGE HAIL AND DAMAGING WIND GUSTS...IT
DOES NOT APPEAR THAT A WW WILL BE NECESSARY ATTM.
HOWEVER...CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED.
SURFACE OBSERVATIONS SHOW A COLD FRONT ADVANCING SWD INTO SRN TX AT
01Z. WARM SECTOR AIRMASS AHEAD OF THE FRONT IS CHARACTERIZED BY
TEMPERATURES IN THE 70S TO NEAR 80 WITH DEWPOINTS IN THE MID TO UPR
60S. BEHIND THE FRONT...A SHARP INVERSION EXISTS ABOVE THE SURFACE
PER 00Z DRT RAOB...THOUGH A SUFFICIENTLY WARM/MOIST LAYER CENTERED
NEAR 850 MB IS AIDING IN MUCAPE VALUES CLOSE TO 1000 J/KG.
COMBINATION OF LARGE-SCALE ASCENT AHEAD OF A SWRN CONUS CLOSED LOW
AND INCREASING CONVERGENCE INVOF THE COLD FRONT APPEARS TO BE AIDING
IN THUNDERSTORM DEVELOPMENT BASED ON RECENT REGIONAL RADAR IMAGERY.
THIS ACTIVITY IS EXPECTED TO STRENGTHEN AND EXPAND IN COVERAGE
DURING THE NIGHT OVER THE REGION AS THE FRONT CONTINUES TO SURGE S
AND EWD. STEEP MIDLEVEL LAPSE RATES NEAR 8 C/KM...MUCAPE VALUES FROM
1000-2000 J/KG...AND EFFECTIVE BULK SHEAR VALUES RANGING FROM 40 KT
OVER THE WARM SECTOR TO 50-70 KT BEHIND THE FRONT WILL FAVOR
SUPERCELLS POSING A THREAT FOR LARGE HAIL. IN ADDITION...STORMS
FORMING CLOSE TO THE LEADING EDGE OF THE SWD MOVING FRONT MAY POSE A
THREAT FOR DAMAGING WIND GUSTS...THOUGH BOUNDARY LAYER COOLING
DURING THE NIGHT MAY DECREASE THE WIND THREAT WITH TIME.
..GARNER.. 03/09/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...HGX...CRP...EWX...
LAT...LON 29559554 27609783 27369892 27729976 28430024 29490010
30229861 30439647 29559554SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 8, 8:58 PM CST | Severe Thunderstorm Watch | SPC | Brooks, Duval, Hidalgo, Jim Hogg, Jim Wells, La Salle and 5 more | 6 hr |
| Mar 8, 11:36 PM CST | Mesoscale Discussion | SPC | Brooks, Dimmit, Duval, Jim Hogg, Jim Wells, La Salle and 3 more | 54 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.