An upper level low in the southwestern US combined with ample instability across West Texas to create numerous severe thunderstorms with one long lived supercell producing a tornado. There were two areas of thunderstorm development late in the afternoon of the 16th.
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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 LUB wrote it up.
An upper level low in the southwestern US combined with ample instability across West Texas to create numerous severe thunderstorms with one long lived supercell producing a tornado. There were two areas of thunderstorm development late in the afternoon of the 16th. The first was in the extreme southeastern Texas Panhandle along a lingering outflow boundary located from northwest Texas into the central Panhandle near Amarillo. The second area was along a dryline in the western South Plains. The lone thunderstorm that developed along the dryline to survive past sunset became a long lived supercell which tracked from Lamb County into Crosby County over several hours. Shortly after this supercell developed in western Lamb County, it produced a brief tornado between Earth and Amherst photographed by several storm chasers. The tornado remained over open land and did not cause any known damage. This supercell would go on to nearly dissipate while over western Hale County. However, it regenerated over central Hale County and would go on to produce a long hail swath of up to three inch diameter hail from central Hale County to Petersburg (Hale County). Meanwhile, widespread thunderstorms developed in the extreme southern Texas Panhandle into the Rolling Plains on a cold pool that moved south out of the central Texas Panhandle. These thunderstorms would produce sporadic severe wind gusts and severe hail.
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 Lubbock, TX wrote its last area forecast discussion before the first event at May 16, 1:44 PM CST, 2 hours 49 minutes earlier.
Area Forecast Discussion National Weather Service Lubbock TX 244 PM CDT Sun May 16 2021 .SHORT TERM... Attention late today was and will continue to be along the dryline, near and just east of the Texas-New Mexico border, where a conditional threat for severe thunderstorms exists. Thunderstorms are uncertain in this region, with various convective-allowing forecast solutions showing isolated dryline eruption in about 40% of outcomes. Should storms develop, they would feed off convective energy levels near 2500-3000 Joules per Kilogram using surface- available energy. But a substantial capping inversion was limiting cumulus growth to this point. Should storms develop there would be a very good chance for becoming severe. And there would be some opportunity to steer activity a little further east toward the central South Plains as well. Also, we are seeing a fairly consistent thunderstorm signal just to our south with indications that these storms, if they were to develop, would split and the left splits tend to drift into the south-central South Plains or southern Rolling Plains. Uncertainty on this feature is somewhat less. By early to mid this evening, whatever dryline storms did or didn't develop should be over. But we will be watching for a likely thunderstorm complex emerging across the Texas Panhandle. Outflows will press to the south mid to late evening and should spread thunderstorm chances as far south as the northern South Plains late this evening, and then across the Rolling Plains late tonight. Severe thunderstorm indices will remain enough to maintain a Slight Risk of severe storms through the night. The outflow should spread across the entire area by daybreak Monday with low level flow easterly trending more toward southeasterly as surface low pressure develops over eastern New Mexico. This should lead to a persistent low level southeast flow Monday with increasing low level convergence late in the day especially on the Caprock across the South Plains and southwest Texas Panhandle. Monday will also feature even higher potential convective energy levels, approaching if not greater than 3500 Joules per Kilogram. A strong upper level low pressure system, closed off near Cal-Nev-Ari this evening will drift east into the southern Rockies by Monday afternoon. This will spread stronger flow aloft and increasing upper divergence across the area. Severe thunderstorms look like a valid threat across the region by late Monday and the Storm Prediction Center already has increased the risk to the Enhanced level, for a combined threat of very large hail, damaging winds, and a couple tornadoes in addition to local flooding. These threats are expected to continue Monday evening - see details just below. RMcQueen .LONG TERM... The core of the mid/upper-level closed low, now centered over the Great Basin in the western U.S., will pivot across the Four Corners region Monday night into Tuesday. Ahead of this approaching low, a vigorous shortwave trough is expected to eject over the western and south-central Great Plains as 500-200 mb flow becomes increasingly difluent. Supercellular convection is expected to be ongoing across the eastern and northeastern Rolling Plains by 18/00Z, and is forecast to morph upscale into a well-organized Mesoscale Convective System (MCS) as large-scale forcing for ascent increases upon the arrival of a 300 mb jet streak near 50 kt moving over the CWA, causing deep- and cloud-layer shear vectors to gradually become unidirectional above the boundary-layer. At the surface, cyclogenesis of a 998 mb low will have already occurred by the evening hours Tuesday, backing surface flow across the low Rolling Plains and into the Edwards Plateau. The isallobaric wind response from the resultant pressure falls as the surface cyclone deepens will cause the quasi-stationary front to drift southward into the northern South and Rolling Plains as the dryline translates westward. Inflow-layer theta-e advection will increase tremendously as a backed low-level jet begins to intensify to near 40-50 kt as the shortwave ejects into western and central Oklahoma, correspondingly enlarging the 0-1/3-km shear vectors within an environment with largely unimpeded and extremely moist/buoyant (i.e. lower 100 mb mean mixing ratios upwards of 14-16 g/kg) low- level storm-relative inflow near 20-30 kt beneath 3,500-4,000 J/kg MLCAPE. Ongoing HP convection that is able to remain cellular during this time (18/00-03Z) will be capable of producing significant-severe hazards, including: 2"+ diameter hail, damaging downdrafts, and tornadoes; especially for right-movers where the ingestion of streamwise vorticity is greatest. Convective morphology is expected to fully evolve into an MCS near 18/05Z (midnight) across the Rolling Plains; however, this may occur sooner depending on the timing of airmass recovery as a function of the vigor of residual outflows affecting the degree of overturning earlier in the day. Regardless, upscale evolution into an MCS will occur with the ongoing convection across the Rolling Plains with additional development forecast to unzip southwestward into the South Plains. As mentioned in the previous forecast assessments over the last two days, precipitable water (PWAT) content exceeding the 99th percentile (i.e. between 1.30-1.60") is expected to advect across the eastern two-thirds of the CWA by late Monday night and early Tuesday. The 12Z RAOBs across South Texas (BRO, CRP, and DRT) this morning sampled PWATs between 1.71-2.03", with the plume advecting northward as per latest METAR observations and GOES-East Blended Total Precipitable Water imagery. The potential for flash flooding will increase by early Tuesday morning, as a belt of southwesterly 850-300 mb mean winds near 30 kt combined with tall, sizable MUCAPE values approaching 4,000 J/kg will exacerbate rain rates per hour within an environment favorable for slow, back-building/training cells oriented relatively perpendicular to the mean convective movement given the magnitude of upshear Corfidi vectors near 10-15 kt. The deepest cores will be capable of producing large hail as well in addition to damaging winds, especially as the cold pools intensify and the shortwave trough rotates over the I-35 corridor, resulting in an eventual east to east-southeastward forward-propagating MCS into the Texas Big Country and Edwards Plateau. As the mid/upper-level low begins to move over the western High Plains on Tuesday, the persistent large-scale forcing for ascent along with the residual (and heavily overworked) EML with MUCAPE values near ~1,000-1,500 J/kg may result in the potential for elevated/non-surfaced based thunderstorms, some of which may be severe. Another vorticity lobe is forecast to round the base of the mid/upper-level trough as the low begins to open may result in additional chances for elevated convection overnight Tuesday into Wednesday as well, with the main hazard of large hail as high-level flow begins to back. Though, any storms that do materialize may very well be short-lived. As the closed low transitions into an open wave and eventually ejects northeastward towards the central Plains, very low chances for severe thunderstorms exists across the eastern Rolling Plains on Thursday with otherwise benign weather elsewhere across the forecast area. Towards the end of the forecast period, an amplifying, positively- to neutrally-tilted trough is forecast to dig into the western U.S. with the possibility of another 500 mb closed low centering over the Great Basin. There has been considerable agreement among numerical weather guidance on this scenario, and should this come to fruition, then multiple episodes of potentially severe weather (including flash flooding) is forecast by the end of the upcoming week and into next weekend across the region. Sincavage && .LUB WATCHES/WARNINGS/ADVISORIES... None. && 05/09
Hazardous Weather Outlook National Weather Service Lubbock TX 1147 AM CDT Sun May 16 2021 TXZ021>044-171700- Parmer-Castro-Swisher-Briscoe-Hall-Childress-Bailey-Lamb-Hale-Floyd- Motley-Cottle-Cochran-Hockley-Lubbock-Crosby-Dickens-King-Yoakum- Terry-Lynn-Garza-Kent-Stonewall- 1147 AM CDT Sun May 16 2021 This Hazardous Weather Outlook is for the South Plains, Rolling Plains and the far Southern Texas Panhandle. .DAY ONE...This afternoon and tonight. Isolated thunderstorms are possible along the dryline late this afternoon, which will be located across the western South Plains near the New Mexico border. If storms develop they will have a risk for quickly becoming severe producing hail to 2 inches or larger, wind gusts to 70 mph and torrential rainfall. In addition, a complex of strong to severe thunderstorms is expected to develop over northeast New Mexico late this afternoon, spreading into the Texas Panhandle and northern South Plains this evening, and then the Rolling Plains later tonight. Wind gusts in excess of 70 mph, hail to 2 inches diameter, and brief heavy rainfall will all be possible with this activity. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Isolated to scattered severe thunderstorms are expected along and east of a dryline Monday afternoon and evening, with significant severe weather possible, favoring the southeast Texas Panhandle and Rolling Plains. The risk for severe weather and flash flooding will expand to include much of the South Plains and Rolling Plains late Monday night into Tuesday as an upper level storm system approaches the region. More opportunities for thunderstorms will exist Wednesday and then again Friday and Saturday. Some of these storms could be strong to severe and produce heavy rainfall. .SPOTTER INFORMATION STATEMENT... Spotter activation will likely be needed. Please relay any information about severe weather to the NWS while following local, state, and CDC guidelines.
The Altus AFB radar (KFDR), 100 km away, was scanning. The volume nearest the first event began at 22:35 UTC.
5 hail, 1 tornado, 1 thunderstorm wind. Local standard time, as filed.
Reports of hail up to ping pong size from law enforcement and an NWS cooperative weather observer in Kirkland. No damage was reported.
A storm spotter reported hail up to ping pong size south of Earth on Farm to Market Road 1055. No damage was reported.
A report was received via social media of half dollar size hail east of Cee Vee.
Numerous storm chasers photographed a brief tornado in an open field about seven miles south of Earth. No known damaged occurred so a rating of EF-unknown was assigned to this tornado.
A report of quarter size hail was received from the public just south of Happy.
A Texas Tech University West Texas mesonet site near Lesley measured severe wind gusts from 2007 CST through 2028 CST. A maximum wind gust of 73 mph was reported at 2028 CST.
An intense supercell thunderstorm, which previously produced a tornado earlier in the evening, produced a large hail swath from approximately six miles south of Hale Center to Petersburg. Numerous reports of hail were received along this path length. Hail sizes ranged from quarter size at the initial report near the intersection of Interstate 27 and Farm to Market Road 37 at 2131 CST to three inches in diameter about five miles northwest of Petersburg at 2157 CST.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2021Every state in 2021This day in weather historyThe tornado archive for Texas, 2021Warnings in Texas, May 2021
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: 950415, 950416, 950417, 950418, 950419, 950420, 950421.