Alert archive / Texas / Tornado Watches in 2007
Tornado Watch 59
The Storm Prediction Center issued this tornado watch at Mar 12, 2007, 4:01 AM CDT for 11 counties in Texas. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 12, 2007, 4:01 AM CDT (09:01 UTC)
- Expired
- Mar 12, 2007, 7:38 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
Counties Austin County, TX, Brazoria County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Harris County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, Waller County, TX, Wharton County, TX
The radar
The Houston radar (KHGX), 57 km from the middle of the area, began a volume at 09:05 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
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 12, 4:28 AM CDT | Severe Thunderstorm Warning | HGX | Austin, Fort Bend, Waller, Wharton | 62 min |
| Mar 12, 4:58 AM CDT | Severe Thunderstorm Warning | HGX | Harris | 62 min |
| Mar 12, 5:03 AM CDT | Severe Thunderstorm Warning | HGX | Brazoria | 42 min |
| Mar 12, 5:08 AM CDT | Tornado Warning | HGX | Harris | 37 min |
| Mar 12, 5:15 AM CDT | Severe Thunderstorm Warning | HGX | Brazoria | 45 min |
| Mar 12, 5:50 AM CDT | Severe Thunderstorm Warning | HGX | Brazoria, Galveston, Harris | 44 min |
| Mar 12, 6:32 AM CDT | Severe Thunderstorm Warning | HGX | Chambers, Galveston | 58 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
Lake Charles Mun, LA (KLCH), launched 00:00Z, 9.0 hours before the alert went out and 248 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
- 9 J/kg
- Mixed-layer CIN
- -2 J/kg
- Mixed-layer LCL
- 968 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 47 m²/s²
- 0-3 km storm-relative helicity
- 53 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
WWUS20 KWNS 120902
SEL9
SPC WW 120902
TXZ000-CWZ000-121300-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 59
NWS STORM PREDICTION CENTER NORMAN OK
405 AM CDT MON MAR 12 2007
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
SOUTHEAST TEXAS
COASTAL WATERS
EFFECTIVE THIS MONDAY MORNING FROM 405 AM UNTIL 800 AM CDT.
TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH OF HOUSTON
TEXAS TO 25 MILES EAST SOUTHEAST OF PALACIOS TEXAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU9).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.
DISCUSSION...WELL ORGANIZED LINEAR MCS WITH SEVERAL EMBEDDED LEWP
STRUCTURES WILL CONTINUE EWD ACROSS SE TX THROUGH THE EARLY MORNING
HOURS. THE LOW LEVELS SHOULD DESTABILIZE SUFFICIENTLY FOR
CONVECTION TO BE BASED AT THE SURFACE...WHILE LOW-LEVEL SHEAR WILL
BE STRONG ENOUGH TO MAINTAIN A THREAT FOR A COUPLE OF TORNADOES AND
A FEW DAMAGING GUSTS WITHIN THE MOIST ENVIRONMENT.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 27030.
...THOMPSONSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 11, 9:09 PM CDT | Mesoscale Discussion | SPC | Atascosa, Bandera, Bexar, Blanco, Burnet, Caldwell and 19 more | 2 hr |
| Mar 11, 11:16 PM CDT | Mesoscale Discussion | SPC | Atascosa, Bexar, Caldwell, Comal, Dimmit, Frio and 8 more | 89 min |
| Mar 12, 1:39 AM CDT | Mesoscale Discussion | SPC | Austin, Bastrop, Bee, Colorado, DeWitt, Fayette and 13 more | 2 hr |
| Mar 12, 5:09 AM CDT | Mesoscale Discussion | SPC | Austin, Brazoria, Chambers, Colorado, Fort Bend, Galveston and 10 more | 96 min |
| Mar 12, 6:10 AM CDT | Mesoscale Discussion | SPC | Hardin, Jasper, Jefferson, Newton, Orange | 95 min |
Nearby
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.