Alert archive / Texas / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 70
The Storm Prediction Center issued this severe thunderstorm watch at Mar 8, 2012, 8:58 PM CST for 11 counties in Texas. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 8, 2012, 8:58 PM CST (02:58 UTC)
- Expired
- Mar 9, 2012, 2:45 AM CST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Brooks County, TX, Duval County, TX, Hidalgo County, TX, Jim Hogg County, TX, Jim Wells County, TX, La Salle County, TX, Live Oak County, TX, McMullen County, TX, Starr County, TX, Webb County, TX, Zapata County, TX
The radar
The Corpus Christi radar (KCRP), 137 km from the middle of the area, began a volume at 02:58 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 8, 9:08 PM CST | Severe Thunderstorm Warning | CRP | Webb | 67 min |
| Mar 8, 9:12 PM CST | Severe Thunderstorm Warning | CRP | La Salle | 63 min |
| Mar 8, 9:52 PM CST | Severe Thunderstorm Warning | CRP | Duval, La Salle, McMullen, Webb | 38 min |
| Mar 8, 10:05 PM CST | Severe Thunderstorm Warning | CRP | Duval, Webb | 25 min |
| Mar 8, 10:08 PM CST | Severe Thunderstorm Warning | BRO | Jim Hogg | 52 min |
| Mar 8, 10:57 PM CST | Severe Thunderstorm Warning | BRO | Jim Hogg | 17 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Corpus Christi, TX (KCRP), launched 00:00Z, 3.0 hours before the alert went out and 155 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.
737
WWUS20 KWNS 090300
SEL0
SPC WW 090300
TXZ000-091000-
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 70
NWS STORM PREDICTION CENTER NORMAN OK
900 PM CST THU MAR 8 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTH TEXAS
EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 900 PM
UNTIL 400 AM CST.
HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 45
STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES NORTHEAST OF
COTULLA TEXAS TO 130 MILES SOUTH SOUTHEAST OF COTULLA TEXAS. FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
DISCUSSION...TSTMS /INCLUDING A SUPERCELL/ HAVE DEVELOPED AHEAD OF
COLD FRONT TONIGHT WITHIN A MOIST...UNSTABLE AIR MASS WITH MUCAPE
VALUES OF 1000-2000 J/KG. CAP OBSERVED ON 00Z CRP/BRO SOUNDINGS IS
LIKELY BEING OFFSET TO SOME DEGREE BY THE STRENGTHENING SLY/SELY
LOW-LEVEL WINDS WHICH IS ENHANCING INFLOW INTO THE ONGOING STORMS.
GIVEN THE PRESENCE OF 50-60 KT DEEP-LAYER SHEAR...ENVIRONMENT WILL
REMAIN FAVORABLE FOR ORGANIZED STORM MODES WITH ATTENDANT THREATS
FOR DAMAGING WINDS AND LARGE HAIL.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 28020.
...MEADSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 8, 7:32 PM CST | Mesoscale Discussion | SPC | Atascosa, Austin, Bandera, Bastrop, Bee, Bexar and 33 more | 88 min |
| Mar 8, 11:36 PM CST | Mesoscale Discussion | SPC | Brooks, Dimmit, Duval, Jim Hogg, Jim Wells, La Salle and 3 more | 54 min |
Nearby
Severe Thunderstorm Watches in Texas, 2012Every severe thunderstorm watch 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.