Isolated thunderstorms formed in a conditionally unstable airmass. Two of these storms sparked structure fires in Austin.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS EWX wrote it up.
Isolated thunderstorms formed in a conditionally unstable airmass. Two of these storms sparked structure fires in Austin.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Austin/San Antonio, TX wrote its last area forecast discussion before the first event at May 9, 11:56 AM CST, 34 minutes earlier.
Area Forecast Discussion National Weather Service Austin/San Antonio TX 1256 PM CDT Tue May 9 2017 .AVIATION... /18Z TAFS/ A slug of locally enhanced pwat values of 1.9 to 2.0 inches is well depicted in the morning model runs and is analyzed in the SPC mesoanalysis. The moisture surge centered near Beeville at noon will move almost due north toward AUS later today, resulting in some afternoon enhancements of deeper convection and numerous lighter showers. Some newly developed deeper convection at the time of this writing is forming over Hays County and looks to skirt just west of the AUS vcnty. With most of the activity remaining as showers, will leave out thunder for the 18Z TAFs and update as needed. Farther west, some light sprinkles could impact DRT with a brief reduction in vsby, but radar trends suggest less coverage and better mixing from gusty surface winds. Later today, dry mid level air should enhance capping and provide less lift going into the latter part of the TAF periods. Some vfr skies are expected for the late afternoon and evening with borderline mvfr/ifr cigs to resume around midnight or shortly afterwards. With good low level moisture pooling and increased capping aloft, will assume most of the midday hours Wednesday to be mvfr. && .PREV DISCUSSION... /ISSUED 324 AM CDT Tue May 9 2017/ SHORT TERM (Today through Wednesday)... Low clouds continue to be in place across the region as strong southerly flow continues in the lower-levels of the atmosphere. A deep upper level low pressure system can be seen on water vapor imagery south of Arizona with deep southwest flow aloft in the mid- levels of the atmosphere in place over Texas. The SW flow is leading to a capping inversion as warmer air near 750 mb advects over the region. This CAP can be seen nicely on the 00z DRT RAOB. Expect this inversion to remain in place for much of the short-term forecast as the upper low slowly moves east. This should overall limit the chances for deep convection as any upward motions originating from the surface would cease once it hits the inversion around 6kft above ground level. Weak ascent within the low-level flow below the CAP should initiate some upward motions which could lead to some weak showers below the inversion this afternoon. Would be surprised to see any lightning this afternoon, but if thunderstorms do develop it would be across the northern Hill Country where CIN values are slightly weaker. High temperatures today will be similar to yesterday as cloud cover is expected to remain in place for much if not all of the day as moisture remains trapped under the inversion. The coverage of expected isolated to scattered showers should diminish overnight with the loss of day time heating, but will keep the mention of some showers for the western counties in slightly closer proximity to the upper low. On Wednesday afternoon, the upper low is expected to be centered over eastern New Mexico with increasing lift expected for the western CWA. This increase in upward motions should help to slightly lift/weaken the CAP for mainly the Edwards Plateau region of the CWA. In addition, a dryline should be pushing east but should mainly remain north of our area. Therefore, the bulk of any shower and thunderstorm activity will be north of the area on Wednesday afternoon. With the weaker CAP, can't rule out some thunderstorms, but the main weather type should be showers for most of the CWA. Where thunderstorms do form, the convective environment could support some strong storms and the Day 2 outlook from SPC does have the northwest CWA in a marginal risk which seems warranted. LONG TERM (Wednesday Night through Monday)... On Thursday, the upper low will be finally ejecting to the northeast with an expected track over the TX Panhandle and into northern Oklahoma. This track would keep the best lift and therefore, the better rain chances to our north as well. However, the dryline is expected to push more into our CWA Thursday afternoon which could help slightly increase the coverage of activity in relation to Wednesday. Thermodynamic and shear profiles again support a marginal risk for severe weather for much of the area through Thursday night. The upper low will finally eject far enough east to allow the associated cold front to move south through the region Friday morning. This should end any additional rain chances from west to east. This front will not have much effect on high temperatures, as clearer skies will actually lead to slightly warmer temperatures for the weekend. However, the drier air will lead to cooler overnight lows on Saturday and Sunday morning. Southerly flow returns on Sunday which will allow those overnight temps to begin to increase once again. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 81 70 82 70 85 / 30 10 30 30 40 Austin Bergstrom Intl Airport 81 70 83 69 85 / 30 10 20 30 40 New Braunfels Muni Airport 81 70 83 70 85 / 40 20 20 30 40 Burnet Muni Airport 78 68 79 67 83 / 40 20 30 30 40 Del Rio Intl Airport 85 71 89 68 89 / 20 40 20 40 20 Georgetown Muni Airport 80 69 81 69 84 / 30 10 30 20 50 Hondo Muni Airport 82 70 83 69 86 / 30 20 30 30 40 San Marcos Muni Airport 81 70 83 70 85 / 30 10 20 30 40 La Grange - Fayette Regional 82 70 86 71 85 / 20 10 10 20 40 San Antonio Intl Airport 81 71 83 70 85 / 40 20 30 30 40 Stinson Muni Airport 82 71 83 71 85 / 40 20 20 20 40 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && Mesoscale/Aviation...Oaks Synoptic/Grids...Allen Public Service/Data Collection...Treadway
Hazardous Weather Outlook National Weather Service Austin/San Antonio TX 513 AM CDT Tue May 9 2017 TXZ171>173-183>194-202>209-217>225-228-101015- Llano-Burnet-Williamson-Val Verde-Edwards-Real-Kerr-Bandera- Gillespie-Kendall-Blanco-Hays-Travis-Bastrop-Lee-Kinney-Uvalde- Medina-Bexar-Comal-Guadalupe-Caldwell-Fayette-Maverick-Zavala- Frio-Atascosa-Wilson-Karnes-Gonzales-De Witt-Lavaca-Dimmit- 513 AM CDT Tue May 9 2017 This Hazardous Weather Outlook is for South-Central Texas.. .DAY ONE...Today And Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Strong to severe thunderstorms are possible Wednesday and Thursday during the afternoon and evening. Wednesday storms will be over the northwestern part of the area and Thursday they will spread across most of the region. The most likely threats will be large hail and damaging winds. .SPOTTER INFORMATION STATEMENT... Spotters should be prepared to report any severe weather.
The Ft Hood radar (KGRK), 44 km away, was scanning. The volume nearest the first event began at 18:30 UTC.
2 lightning. Local standard time, as filed.
A thunderstorm produced lightning that caused a house fire in northwestern Austin. The fire caused the roof of the house to collapse.
A thunderstorm produced lightning that caused an apartment fire in northern Austin. Ten apartment units were affected.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2017Every state in 2017This day in weather historyWarnings in Texas, May 2017
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 698110, 698111.