Alert archive / Texas / Tornado Watches in 2020
Tornado Watch 178
The Storm Prediction Center issued this tornado watch at May 12, 2020, 10:48 AM CDT for 14 counties in Texas. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- May 12, 2020, 10:48 AM CDT (15:48 UTC)
- Expired
- May 12, 2020, 5:00 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
Counties Bastrop County, TX, Bexar County, TX, Blanco County, TX, Caldwell County, TX, Comal County, TX, Fayette County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Kendall County, TX, Lee County, TX, Travis County, TX, Williamson County, TX, Wilson County, TX
The radar
The Austin/San Antonio radar (KEWX), 36 km from the middle of the area, began a volume at 15:49 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
- 10%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 12, 10:50 AM CDT | Tornado Warning | EWX | Bexar, Comal, Kendall | 25 min |
| May 12, 10:53 AM CDT | Tornado Warning | EWX | Bastrop, Lee | 37 min |
| May 12, 11:10 AM CDT | Tornado Warning | EWX | Lee | 35 min |
| May 12, 11:14 AM CDT | Severe Thunderstorm Warning | EWX | Bexar, Comal, Kendall | 61 min |
| May 12, 11:25 AM CDT | Tornado Warning | EWX | Bastrop, Lee | 35 min |
| May 12, 11:28 AM CDT | Flash Flood Warning | EWX | Comal | 3 hr |
| May 12, 11:41 AM CDT | Severe Thunderstorm Warning | EWX | Lee | 34 min |
| May 12, 11:52 AM CDT | Flash Flood Warning | EWX | Hays, Travis | 3 hr |
| May 12, 11:55 AM CDT | Tornado Warning | EWX | Lee | 35 min |
| May 12, 12:23 PM CDT | Tornado Warning | EWX | Comal, Hays | 19 min |
| May 12, 12:27 PM CDT | Severe Thunderstorm Warning | EWX | Lee | 18 min |
| May 12, 3:14 PM CDT | Severe Thunderstorm Warning | EWX | Gonzales | 20 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 12:00Z, 3.8 hours before the alert went out and 264 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
- 1021 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 847 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 57 m²/s²
- 0-3 km storm-relative helicity
- 155 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 5.5
The text
As transmitted.
960 WWUS20 KWNS 121544 SEL8 SPC WW 121544 TXZ000-122200- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 178 NWS Storm Prediction Center Norman OK 1045 AM CDT Tue May 12 2020 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of A small part of central Texas * Effective this Tuesday morning and afternoon from 1045 AM until 500 PM CDT. * Primary threats include... A couple tornadoes possible Isolated damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...A small convective system across central Texas will likely persist into the afternoon, with embedded supercells capable of producing a couple of tornadoes. The tornado watch area is approximately along and 45 statute miles north and south of a line from 30 miles northwest of San Antonio TX to 55 miles east southeast of Austin TX. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... 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. && 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 550. Mean storm motion vector 22020. ...Thompson
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 11, 8:42 PM CDT | Mesoscale Discussion | SPC | Crane, Pecos, Terrell, Upton, Ward | 93 min |
| May 11, 8:45 PM CDT | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Castro, Childress, Cochran and 34 more | 90 min |
| May 11, 10:39 PM CDT | Mesoscale Discussion | SPC | Borden, Briscoe, Childress, Cottle, Crosby, Dawson and 15 more | 96 min |
| May 12, 10:00 AM CDT | Mesoscale Discussion | SPC | Bastrop, Bexar, Blanco, Burleson, Burnet, Caldwell and 11 more | 2 hr |
| May 12, 2:12 PM CDT | Mesoscale Discussion | SPC | Bastrop, Bexar, Blanco, Burleson, Burnet, Caldwell and 16 more | 93 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.