An upper level shortwave trough moved through West Texas and interacted with a dryline to generate thunderstorms. The airmass was strongly unstable with only modest vertical wind shear and high precipitable water.
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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.
An upper level shortwave trough moved through West Texas and interacted with a dryline to generate thunderstorms. The airmass was strongly unstable with only modest vertical wind shear and high precipitable water. Storms evolved into a line as they moved across South Central Texas producing large hail, damaging wind gusts, and one tornado. They also produced heavy rain that led to flash flooding.
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 24, 5:36 AM CST, 1 hour 34 minutes earlier.
Area Forecast Discussion National Weather Service Austin/San Antonio TX 636 AM CDT Sun May 24 2020 .AVIATION... MVFR cigs have developed over the I-35 sites and AUS has even seen some IFR cigs. DRT should also see some MVFR conditions build in this morning as some low clouds can be seen building north out of Mexico on satellite. Should see improvement to VFR at the I-35 sites by 16Z and at DRT by 18-19Z. There is a chance for a few pop- up showers and storms at the I-35 sites this morning and although its not a guarantee the terminals will be impacted, confidence is high enough to include some tempo groups to cover this potential. However, there is higher confidence in the development of a line of strong storms late this afternoon that would likely impact DRT in the 23Z- 03Z Monday time frame, then reach the I-35 sites after that. Gusty winds and large hail are possible with these storms in addition to heavy rainfall that could reduce visibility to as low as 2 miles. Following their passage, MVFR cigs are likely to redevelop tonight. && .PREV DISCUSSION... /ISSUED 424 AM CDT Sun May 24 2020/ UPDATE... Although precipitation has ended over the area, a wake low appears to have developed over central portions of the region. Hondo gusted to 53 mph a couple hours ago despite only weak returns on radar, and in the last hour some 28-32 mph gusts have been reported in Bexar County. could see this breeziness continue for another 1-2 hours, perhaps reaching portions of Comal, Guadalupe, or Wilson Counties. Will then need to watch for isolated to scattered thunderstorm development through the morning mainly north and east of San Antonio as most high resolution guidance depicts this occurrence. Will increase POPs slightly along the I-35 corridor from slight chance to low end chance. PREV DISCUSSION... /ISSUED 300 AM CDT Sun May 24 2020/ SHORT TERM (Today through Monday)... Early this morning, a few areas of showers remain, with small pockets of showers over our easternmost counties and some lingering showers stretching from Atascosa County to Dimmit County. A remnant, mostly no-longer-precipitating MCV was noted near Llano County at 08Z, and the activity to the south may leave some remnant boundaries as well that could serve as a focal point for redevelopment of some isolated daytime activity for Sunday. Although not a guarantee, a few thunderstorms would be possible and could drop a quick, localized 0.5+" of precipitation but would be unlikely to be severe. Despite mostly cloudy skies, with southeasterly winds and no widespread daytime precipitation have opted to raise daytime highs today into the mid 80s to lower 90s. This is more in line with bias corrected guidance which has performed well the last several days under a similar regime. The main story through the short term perioD will be the development of a line of strong to severe thunderstorms late this afternoon that will move west to east across the area tonight. An upper level disturbance will move in from the west and provide lift and a dryline closer to the Big Bend region should be a sufficient trigger. CAPE on the order of 2500-3500 J/kg should be available over southern and western portions of our area, with somewhere in the neighborhood of 35 knots of effective shear. Initially, large to very large hail as well as damaging winds will be a threat near the Rio Grande, and although the hail threat will gradually diminish as storms move eastward, the entire CWA is under a slight risk of severe storms from the SPC for this event. The environment will not be supportive of a tornado threat. There is still some timing uncertainty but storms will most likely move in from the west after 3-4pm, reaching the I-35 corridor as early as 7pm but likely closer to 9. The main threat would be east of the main population centers no later than 3am and only some lingering showers and a few rumbles of thunder would be expected after that. In addition to the severe threat, these storms may also produce locally heavy rain. Precipitable water values of 1.5-2" are expected as 850 mb southeasterlies increase and pump additional moisture into the region. These storms will likely drop 1-3" across a significant portion of the area and locally higher amounts, potentially as much as 4-5" per ensemble maxima. The best chance for these higher amounts appears to be in the region east of Del Rio and west of a line approximately from western DeWitt County to Burnet, which the WPC has highlighted in a slight risk area for todays Excessive Rainfall Outlook. A marginal risk is outlined elsewhere. Monday, there appears to be a chance once again for a few developing showers and storms, especially east, but we will have a better handle on whether or not there will be enough instability behind tonights event to support this chance. It will be cooler regardless with highs in the lower 80s north and upper 80s south. LONG TERM (Monday Night through Saturday)... As the upper level low settles over Texas, a surface boundary drifts across our area Monday night into Tuesday. Moisture convergence along this feature and upward forcing by the upper level low and surface boundary generate isolated showers and thunderstorms that gradually form into a line or lines of showers and thunderstorms. Strong instability and steep lapse rates indicate another potential of strong to severe storms with large hail and damaging winds. The upper level low drifts east a little allowing our area to be on the southwestern quarter of the low on Wednesday. Somewhat more stable air filters into western parts of our area ending rain chances there briefly. Meanwhile, sufficient moisture and upward forcing remains for slight to low chances of showers and thunderstorms across eastern parts of our area. The upper level low drifts back to the southwest on Thursday through Saturday to more directly overhead or just of our area. Chances of showers and thunderstorms increase along with a potential of more rounds of locally heavy rains and strong storms due to increased PWs, instability, and lapse rates. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 89 68 82 67 82 / 30 80 50 70 60 Austin Bergstrom Intl Airport 90 67 83 66 82 / 30 80 50 70 60 New Braunfels Muni Airport 90 67 84 66 82 / 40 80 50 70 60 Burnet Muni Airport 87 65 81 64 79 / 40 70 50 70 60 Del Rio Intl Airport 89 68 88 68 86 / 50 60 20 70 40 Georgetown Muni Airport 89 67 82 66 81 / 30 70 50 70 60 Hondo Muni Airport 92 68 87 67 85 / 40 80 40 60 50 San Marcos Muni Airport 90 67 84 66 82 / 40 80 50 70 60 La Grange - Fayette Regional 88 69 84 68 82 / 40 80 60 60 60 San Antonio Intl Airport 91 68 85 68 83 / 40 80 50 70 60 Stinson Muni Airport 91 70 85 68 83 / 40 70 50 70 60 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && Short-Term/Aviation...KCW Long-Term...04
Hazardous Weather Outlook National Weather Service Austin/San Antonio TX 322 AM CDT Sun May 24 2020 TXZ171>173-183>194-202>209-217>225-228-250830- 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- 322 AM CDT Sun May 24 2020 This Hazardous Weather Outlook is for South-Central Texas.. .DAY ONE...Today And Tonight. There is a slight risk of severe thunderstorms late this afternoon through tonight. Hail in excess of 1 inch (perhaps as large as 2 inches west of a line from Rock Springs to Eagle Pass) and damaging wind gusts as well as locally heavy rain potentially leading to minor flooding impacts are all possible. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Rain chances continue through Tuesday. Strong storms and locally heavy rainfall will return to the forecast on Monday night into Tuesday. Although Wednesday looks less wet, shower and thunderstorm chances will remain in the forecast Thursday into next weekend and concerns for flooding may return. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed later today through tonight and again Monday night.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
453 AM CDT SUN MAY 24 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0216 AM NON-TSTM WND GST 2 NW HONDO 29.37N 99.17W
05/24/2020 M61 MPH MEDINA TX ASOS
ASOS STATION KHDO SOUTH TX RGNL ARPT AT
HONDO.
&&The Austin/San Antonio radar (KEWX), 74 km away, was scanning. The volume nearest the first event began at 13:07 UTC.
12 hail, 9 thunderstorm wind, 5 flash flood, 1 tornado. Local standard time, as filed.
A thunderstorm produced wind gusts estimated at 75 mph that displaced a fence and damaged a gazebo in the Waterford Park neighborhood in Helotes.
A thunderstorm produced quarter size hail in Manor. This report came from mPING.
A thunderstorm produced quarter to half dollar size hail around Manor. Reports came from amateur radio and mPING.
A thunderstorm produced quarter size hail near Camp Swift.
A thunderstorm produced quarter size hail just west of Giddings.
A thunderstorm produced quarter size hail in South Austin.
A thunderstorm produced half dollar size hail in South Austin. This report was from mPING.
A thunderstorm produced ping pong ball size hail in South Austin.
A thunderstorm produced ping pong ball size hail in South Austin. This report was from mPING.
A thunderstorm produced half dollar size hail at Garner State Park.
A thunderstorm produced wind gusts estimated at 85 mph that blew off part of an awning from a building near downtown Eagle Pass.
A thunderstorm produced wind gusts measured at 53 kts. at the Love Creek Preserve between Vanderpool and Medina.
A thunderstorm produced quarter size hail in Austin. This report was from mPING.
A thunderstorm produced golf ball size hail near Austin Bergstrom International Airport. There was a picture of the hail on social media.
Thunderstorms produced heavy rain that led to flash flooding. Parts of I-35 that were under construction were flooded as were streets in the area. CoCoRaHS observers reported 2.5 to 3 inches of rain.
A thunderstorm produced quarter size hail in South Austin.
A thunderstorm produced wind gusts measured at 61 kts. by the ASOS at the South Texas Regional Airport in Hondo.
A National Weather Service storm damage survey found a wide swath of 60 to 70 mph winds caused extensive tree damage to areas near Cartwright Trail, Talley Rd., and along Culebra Rd. Fences were blown down, sheds overturned, and some roofs were damaged.
A thunderstorm produced wind gusts estimated at 80 mph that uprooted trees in Fair Oaks Ranch. This report was from mPING.
Thunderstorms produced heavy rain that led to flash flooding in South Austin. An mPING report stated streets were flooded near Old Manchaca Rd. near a creek called Nichols Branch.
An NWS damage survey concluded that a small EF1 tornado touched down in the Wildhorse subdivision, between Loop 1604 and the Government Canyon State Natural area on the west side of Bexar County. A large severe storm was moving northeast through the area just after 7 PM when it appears a tornado developed near the Flying Fury Dr. cul-de-sac and neighborhood drainage ditch. There was minor damage on Flying Fury with substantial roof damage to several homes on the east side of Palomino Path as the tornado moved northeast. Several of the homes had broken windows, large sections of roof lifted off, along with puncture marks from flying debris on many of the exterior walls. The maximum winds were reached at this location and were estimated to be 100 mph. The tornado continued moving northeast, taking down a fence at the end of Palomino Path before likely dissipating near the Wildhorse HOA Sports Park and open field/drainage area.
An NWS storm survey found thunderstorms produced wind gusts estimated at 70 mph that damaged roofs and fences off Grey Fox in far northwest San Antonio.
A thunderstorm produced wind gusts estimated at 70 mph that downed tree limbs near the intersection of Evans Rd. and Bulverde Rd. in far north San Antonio.
Thunderstorms produced heavy rain that led to flash flooding. In north San Antonio, southbound Hwy 281 near Brook Hollow Blvd. was closed and a car was stalled in water.
A thunderstorm produced wind gusts estimated at 80 mph that snapped a large tree at its base. There was a picture of the tree on social media.
Thunderstorms produced heavy rain that led to flash flooding. Bexar County Emergency Management reported multiple high water rescues.
Thunderstorms produced heavy rain that led to flash flooding closing streets in the vicinity of Jackson Keller Rd. and San Pedro Ave. in north San Antonio.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2020Every state in 2020This day in weather historyThe tornado archive for Texas, 2020Warnings in Texas, May 2020
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: 891230, 891231, 891232, 891233, 891234, 891235, 891236, 891237, 891238, 891239, 891240, 891241, 891242, 891243, 891244, 891245, 891246, 891253, 891262, 891256, 891257, 891259, 891260, 891274, 891263, 891264, 891265.