1). March 23, 6:30 PM - Interception and observation of a severe thunderstorm in Oldham / Potter County, Texas and west of Amarillo along Interstate 40. The storm was a supercell storm developing on the south side of a cluster of strong and severe thunderstorms. The core of the storm was not penetrated, but most likely contained large hail. Conditions encountered were occasional lightning, some rain, and strong winds gusting near 60 MPH. Dust was kicked up making it difficult to see the storm structure, but striations and the RFD clear slot was noticeable. Conditions causing the storm were a dryline, low pressure system, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was valid for the area until 10 PM CDT.

2). March 24, 8:30 PM - Observation of a strong to possibly severe thunderstorm along I-20 and west of Marshall in Harrison County, Texas. The storm was a multicell segment of storms that acquired a pronounced bow structure after passing by. Very heavy rains, lightning, and winds near 45 MPH were encountered with this line segment. A possible tornado also developed in the northern portion of this bow segment from Marshall and northeastward. This would have been entirely rain wrapped and not visible in daylight anyway. Conditions causing the storm were a pacific front (overtaking a dryline), low pressure trough, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 3 AM CDT the following day.

3). March 26, 1:00 PM - Observation of a strong to severe thunderstorm from Chickasha, Oklahoma in Grady County and near Highway 81. The storm was part of an elevated complex of strong and severe thunderstorms. Light to moderate rain, occasional lightning, and pea to dime sized hail was observed with this storm. Conditions causing the storms were a low level jet and strong upper trough. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills.

4). March 26, 5:00 PM - Observation and penetration of a very severe and tornadic thunderstorm from near Tatums, Oklahoma to near Byars and Konawa, and in Garvin and McClain counties near Highways 19, 133, and 59. This storm was a classic supercell storm. The core was not directly penetrated but hail in excess 2" (most stones were smaller and quarter sized) was observed on the edge of the hail core, causing minor damage to the vehicle. An isolated hail stone to tennis ball sized was also noted smashing into the road. A low wall cloud and funnel was noted near Pauls Valley. A developing weak tornado was briefly visible with this storm south of Konawa looking northwest from Highway 3W. The storm also contained heavy rains, 50 MPH winds, and frequent lightning. Conditions causing the storm were a dryline, low pressure area, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 11 PM CDT.

5). March 26, 7:00 PM - Observation of an extremely severe and tornadic thunderstorm to the east of Ada, Oklahoma in Ponotoc County near Highway 48 north of Lula. The storm was an LP to classic supercell thunderstorm. The storm had a striking visual appearance, appearing as a "spaceship" with striated updraft and vault, when viewed from the east. A well documented tornado was also observed with this storm as well north of Lula. The core of the storm was not penetrated, but contained hail exceeding baseball sized. Impact sounds from the hail (sounded like gun shots) could be heard to my northwest on the edge of the hail core at 1-2 mile distance! Largest hail at my location was widely spaced quarter sized, along with frequent lightning, light rain, and 50 MPH winds (mainly inflow). The tornado itself was a cone funnel that evolved to a long rope that wrapped around a portion of the wall cloud. This feature remained over rural areas and did no damage. Conditions causing the storm were a dryline, low pressure area, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 11 PM CDT.

6). March 26, 8:00 PM - Observation and penetration of a strong thunderstorm to the southwest of Coalgate, Oklahoma along Highway 31 in Coal County. This storm was part of a multicell line of strong and severe storms. Frequent lightning (with some close hits), torrential rains, 50 MPH winds, and small hail were observed with this storm. Conditions causing the storm were a pacific front (overtaking a dryline), low pressure trough, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 11 PM CDT.

7). March 28, 3:30 PM - Observation of a severe thunderstorm to the west and northwest of Matador, Texas in Motley County and near Highways 62 and 70. The storm was a slightly elevated HP supercell storm. A large slowly rotating wall cloud was observed with some small funnels and possible a brief weak tornado. The storm was in very poor visibility and was undercut by cooler air and in an environment of more stable air. The core (containing golfball sized hail) was not penetrated. Lightning and moderate rain was encountered. Conditions causing the storm were a dryline, low pressure area, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 11 PM CDT.

8). March 28, 4:30 PM - Observation and penetration of a very severe and possibly tornadic thunderstorm to the south and southwest of Guthrie, Texas and west of Highway 83 in King County. This storm was a powerful HP supercell, with a wall cloud that rapidly rotated and occluded. When viewed from the east and northeast, looking WSW, a brief tornado was observed with dust and tagging rain curtains before being obscured by (wet) RFD rain wrap (descending reflectivity core). Small hail, 60 MPH winds, frequent lightning, and torrential rains were also observed while proceeding southward through the RFD winds as the storm was completely rain wrapped. Conditions causing the storm were a dryline, low pressure area, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 11 PM CDT.

9). March 28, 6:00 PM - Interception, observation, and penetration of an extremely severe and tornadic thunderstorm in Haskell County, Texas near Highways 277 and 6 from Stamford to east of Haskell. The storm was part the "tail end Charley" cluster of supercell storms at the southern end of a messy cluster of supercells arcing along a dryline bulge. One supercell in this cluster (there were three with the strongest tornadic one in the middle) was a cyclic supercell storm. A large stove pipe tornado was encountered with this storm once clearing the precipitation core from the north (I managed to miss the large hail) through the south side of Stamford. Fortunately, the tornado missed the town. The storm was followed north and east around Lake Stamford and it subsequently became outflow dominated northwest of Throckmorton, Texas. Strong winds to 70 MPH, small hail, and frequent lightning was also observed with this storm. Conditions causing the storm were a dryline, low pressure area, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 11 PM CDT.

10). March 29, 2:30 AM - Observation of a strong to possibly severe thunderstorm off I-35 at a stationary location (hotel) in Denton, Texas in Denton County. The storm was part of a line of strong and severe thunderstorms moving through the area. Heavy rains, small hail, frequent lightning, and winds to near 60 MPH were encountered. Conditions causing the storm were a low pressure trough, upper trough, and low level jet. A 2017 Hyundai Accent was involved with chasing these storms. A severe thunderstorm watch was also valid for the area until 4 AM CDT.

11). March 29, 7:00 PM - Observation of a strong thunderstorm near De Kalb in Bowie County, Texas and along and to the north of Highway 82. The storm was a low topped LP supercell with a flared out base, corkscrewed updraft, and core of small hail. The storm core was not encountered. Conditions causing the storm were a dryline, low pressure trough, upper trough, and surface heating. A 2017 Hyundai Accent was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 12 AM CDT the following day.

This concludes the chase log for the central US Plains (including chases in Arkansas, Louisiana, Oklahoma, and Texas) chase trip for March 23-30, 2017. The summary includes a total of 11 observations, out of which there were 9 severe thunderstorms and 2 strong thunderstorms. 3 tornadoes were observed from three of the severe storms. The main chase vehicle conducting this chase were two 2017 Hyundai Accents (one for March 23rd to the 27th, and another from the 27th to the 30th, both nearly identical). This information was prepared exclusively for the National Weather service and the team of Skywarn storm spotters.

1). April 19, 5:15 PM - Interception and indirect penetration of a very severe, and possibly tornadic thunderstorm in Cass County, Nebraska to the southeast of Lincoln, and near Eagle along Highway 34. The storm was a classic supercell storm developing in a line segment of strong and severe storms. A large area of rotation, and possible tornado was noted looking west and approaching the storm from the east. The storm weakened but a rotating wall cloud was noted near Manley along SR 1. The core of this storm was not directly penetrated, but had hail up to 2". Penny sized hail, 50 MPH winds, heavy rains, and occasional lightning was noted during my encounter with this storm. Conditions causing the storm were a Pacific front (overtaking a dryline), low pressure trough, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 10 PM CDT.

2). April 19, 7:30 PM - Interception and indirect penetration of a severe thunderstorm from Otoe County, Nebraska along Highway 75 and SR 2 and eastward into Fremont and Page Counties, Iowa towards Bedford. The storm was a small HP supercell embedded in a line segment. A wall cloud and hail core was observed with this storm before it became outflow dominant and weakened into a line segment. The core was not directly penetrated. Lightning, heavy rains, small hail, and 50 MPH winds were encountered. Conditions causing the storm were a Pacific cold front, low pressure trough, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 10 PM CDT.

3). April 20, 10:30 PM - Interception, observation, and indirect penetration of a very severe thunderstorm to the northwest of Vernon, Texas and southwest of Altus, Oklahoma near and south of the Red River along Highway 283, mainly in Wilbarger County, Texas. The storm was one of a few intense elevated supercell storms (north of a stationary front to the south). The core of this storm was not directly penetrated, but contained hail to tennis ball sized (with vertically-integrated liquid / VIL of ~80)! Penny sized hail, heavy rains, 50 MPH winds, and frequent (nearly continuous) lightning with many close hits was encountered with this storm. The storm also had a striking visual appearance (lightning illuminated) with "stacked plates" when viewed from the east. Conditions causing the storm were a stationary front, low pressure trough, upper trough, and intensifying low level jet. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was valid for the area until 5 AM CDT the following day.

4). April 21, 9:00 AM - Observation of a severe thunderstorm in Lawton, Oklahoma in Comanche County near I-44 and SR 7 from a stationary location. The storm was the southern end of a line segment of severe thunderstorms. The storm gust front struck; with winds gusting over 60 MPH. Sporadic lightning and heavy rain was also observed after the passage of the gust front surge. Blowing dust and some light debris was noted blowing around. Conditions causing the storms were a low pressure trough, surging outflow boundary, upper trough, and low level jet. A 2016 Jeep Wrangler was used to observe the storms. Documentation was audio and HD video. A severe thunderstorm watch was valid for the area until 12 PM CDT the following day.

5). April 21, 7:00 PM - Interception and observation of a very severe thunderstorm from near Durant, Oklahoma and eastward on Highway 70 to the west of Hugo and near Bennington in Bryan County. The storm was a classic supercell storm, which evolved to HP and later down-scaled to a weak line-segment at dusk. The storm core was not penetrated but probably contained very large hail. A large wall cloud and funnels were also observed with the inflow region of this supercell. The storm also had sporadic lightning and a striking visual appearance ("stacked-plates"). Conditions causing the storm were a prefrontal wave, Pacific cold front, low pressure trough, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 1 AM CDT the following day.

6). April 25, 7:30 PM - Interception and observation of severe thunderstorms from near Burbank to Pawnee in Pawnee County, Oklahoma along Highway 64 and points eastward. The storm started out as a small supercell strong storm, which back-built and evolved into a storm cluster, with an embedded HP supercell. The mail hail core was not penetrated (contained hail to golfball sized). Small hail, 60 MPH winds, very heavy rains, and frequent lightning was observed with this storm. A wall cloud was also noted, but quickly occluded as the storm weakened. Conditions causing the storm were a Pacific cold front, low pressure trough, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was valid for the area until 2 AM CDT the following day.

7). April 25, 10:00 PM - Interception and observation of severe thunderstorms to the southwest of Tulsa, Oklahoma near I-44 and Sapulpa in Creek County. The storm was an HP supercell storm that was on the southern end of a line segment of severe thunderstorms. The storm quickly evolved to a cluster of strong and severe storms. The core was not directly penetrated. Frequent lightning and heavy rains were observed. Small hail (pea to dime sized) and 50 MPH winds were also encountered at a stationary location near Sapulpa. Conditions causing the storm were a Pacific cold front, low pressure trough, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was valid for the area until 2 AM CDT the following day.

8). April 26, 4:00 PM - Observation of severe thunderstorms from east and southeast of Texarkana mainly in Lafayette and Columbia Counties in Arkansas, from near I-30 and southward to near Highways 82 and 371. The storms were part of a line of strong and marginally severe storms. Heavy rains, 50 MPH winds, sporadic lightning, and small hail were encountered in some of these areas. Conditions causing the storm were a Pacific cold front, low pressure trough, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills. A severe thunderstorm watch was valid for the area until 5 PM CDT.

9). April 29, 6:00 PM - Interception and penetration of an extremely severe and violent tornadic thunderstorm in Van Zandt County, Texas between Eustace and Tundra and west of SR 19 and southeast of Mabank. The storm was an HP supercell storm, the middle one in a cluster of three supercells. A brief view of a multivortex tornado was noted looking southwest as the storm occluded, meanwhile a stronger violent tornado was on-going to the WNW (rated EF-4). A brief glimpse of the edge of the EF-4 tornado (that tracked from Eustace to the west of Canton) was noted barely visible through the rain and hail. The core was not directly penetrated, but hail to golfball sized was observed with 65 MPH winds and torrential rains. The storm also produced frequent lightning with some close hits. The tornado quickly became obscured in rain and damage was mainly to trees. Conditions causing the storm were a prefrontal convergence ahead of a Pacific cold front, low pressure area, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 10 PM CDT.

10). April 29, 6:30 PM - Interception and observation of an extremely severe and violent tornadic thunderstorm in Van Zandt County, Texas from near Tundra along SR 19 and north ands east into Canton and eventually Fruitvale. The storm was violent classic supercell storm, and was the southern storm in a cluster of tornadic supercells. The storm produced a highly visible and well documented wedge tornado just east of SR 19 and northward across I-20. The storm also had a striking visual appearance. The tornado hit parts of Canton and Fruitvale, Texas causing deaths and destruction (probably EF-3 or higher damage). Many homes and businesses, including a car dealership, were completely destroyed. Cars also mangled and flipped. High tension transmission lines were also downed by the tornado with a very loud roar noted. The wedge tornado was 1/2 a mile, and maybe as wide as a mile. Frequent lightning with close hits, isolated hail to golfball sized, torrential rains, and winds gusting over 70 MPH (RFD) were also encountered with this storm. Conditions causing the storm were a prefrontal convergence ahead of a Pacific cold front, low pressure area, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was valid for the area until 10 PM CDT.

11). May 10, 4:30 PM - Interception and direct penetration of a very severe (and briefly tornadic) thunderstorm from north of Matador, Texas on ranch road 94 in Motley County and north and eastward through Childress County along Highways 62 and 287 east-southeastward to near Quanah, then north and northeastward on Highway 6 to near Altus in Jackson County, Oklahoma. The storm was a classic to HP supercell storm. There was a report of a weak / brief tornado on this storm west of Baker, Texas. The possible tornado was not observed. Passage was done through the storm core and "hook". Hail up to tennis ball sized (2.25") was encountered, with most stones 2". An isolated stone to 3" (baseball sized was seen smashing into the roadway). 60 to 65 MPH winds, torrential rains, and frequent lightning were also observed with this storm. Once east of the storm, a large RFD clear slot, rotating wall cloud, and striking ("stacked plates") visual appearance was noted looking WNW at the supercell. The hail guards were installed for this chase on the Jeep. No windows were lost. The hood was severely dinged by the larger hail-strikes. A small crack was noted in the windshield from a stone that bounced off the roadway. Other vehicles were severely damaged by the hail. Trees had some leaves shredded. Some trees and signs were blown down, and power knocked out. Severe flooding was observed near Altus, Oklahoma, as the supercell storm evolved into a complicated MCS of severe thunderstorms. Conditions causing the storm were a dryline, stationary frontal boundary, low pressure area, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills, audio, and HD video. A tornado watch was valid for the area until 10 PM CDT.

12). May 10, 7:00 PM - Interception and penetration of a very severe (and also briefly tornadic) thunderstorm from near Odell and Chillicoth in Wilbarger county, Texas west of Highway 283, then back towards 287 to near Oklaunion, Texas then north on Highway 183 through Davidson and Frederick in Tillman county, Oklahoma then east on SR 5 to near Chattanooga. The storm began as an LP supercell storm southwest of Odell, Texas, and evolved to a classic supercell, then eventually undergone up-scale evolution to an HP storm, and finally a line segment / large MCS after dark. A possible weak and dusty tornado was observed near and north of Davidson, Oklahoma while along 183 south of Frederick. The storm also contained hail to 2", winds gusting near 70 MPH, torrential rains, and frequent lightning (with some close hits). The storm had a striking visual appearance, especially during its early stages. The storm also had a pronounced RFD clear slot and wall cloud before becoming outflow dominated later in its life cycle. Conditions causing the storm were a dryline, stationary frontal boundary, low pressure area, upper trough, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills, and HD video. A tornado watch was valid for the area until 10 PM CDT.

13). May 11, 3:30 PM - Interception and direct penetration of a very severe (and briefly tornadic) thunderstorm from east of Kingfisher, Oklahoma in Logan County and Highway 77, and eastward through Guthrie and Perkins along SR 33 in Payne County, then to Cushing and west of Tulsa in Pawnee County and near Highway 64. The storm was an HP supercell storm that ended as a complex line segment by the end of the period (late afternoon) near Tulsa. A very brief tornado / gustnado occurred with this storm near Perkins, then later after we abandoned the storm well to the northeast of Tulsa near Owasso. The tornadoes were not observed. A spectacular gust front / shelf cloud (as well as undercut RFD cut and wall cloud) were observed with the storm during HP to bow-segment evolution. Extremely large hail was encountered in the core of the HP supercell, with some stones noted to 2.25" (tennis ball sized) and hail drifting from smaller stones on the roadside. The storm also backed winds exceeding 70 MPH, lightning, and violent rain. Conditions causing the storm were a dryline / Pacific front, stationary frontal boundary, low pressure area, upper level low, and surface heating. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills, audio, and HD video. A severe thunderstorm watch was valid for the area until 9 PM CDT.

14). May 11, 7:30 PM - Observation of a strong thunderstorm near I-35 and on the south side of Oklahoma City in Oklahoma County, Oklahoma. The storm was a small elevated LP supercell storm in a small line segment of strong thunderstorms. The storm contained small hail, light to moderate rain, 30 MPH winds, and occasional lightning. The storm had a very striking visual appearance (with striations and a "stacked plates" presentation) when viewed from the ENE. Conditions causing the storm were very cold air aloft, associated with an upper-level low, surface heating, and post-frontal (elevated) forcing in the mid-levels. The storm developed over an area of cool temperatures and winds from the NW. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills. A severe thunderstorm watch was valid for the area until 9 PM CDT.

15). May 14, 4:30 PM - Observation of a strong to marginally severe thunderstorm in Potter County, Texas along Highway 87 / 287 between Dumas and Amarillo. The storm was a marginal supercell storm with a high base that evolved to a line segment. The storm produced light to moderate rain, occasional lightning, small hail, and winds gusting near 60 MPH (mainly in small microbursts). Conditions causing the storm were surface heating, upslope wind flow, a lee surface trough, and a dryline. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills.

16). May 14, 6:30 PM - Observation of strong to severe thunderstorms from near I-24 in Potter County, Texas eastward to Armstrong County through the Palo Duro Canyon near Wayside and SR 207 northward to near Claude. The storm was a cluster of strong and severe thunderstorms. The storms were also high based, and produced light to moderate rain, frequent lightning, and winds gusting near 60 MPH. The core of the storm was not penetrated directly, and a large hail shaft was visible over the canyon back-drop. A small high-based funnel was also observed with a cell that aqcuired LP characteristics near Claude. Conditions causing the storm were surface heating, upslope wind flow, a lee surface trough, and a dryline. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills.

17). May 15, 6:30 PM - Interception and observation of a very severe, and later possibly tornadic thunderstorm from near Stinnet in Hutchinson County, Texas and northeastward towards Spearman in Hansford and Ochiltree Counties along SR 207 and eventually from near Highway 83. The storm was a classic supercell storm, and a large funnel cloud / possible tornado was observed late in the storms life cycle at roughly 9:15 PM looking NW from Highway 83 towards Waka, Texas. The storm had a very striking visual appearance during its mature stages, with a "stacked plates" appearance, and impressive RFD clear slot as well. Hail up to 2" was also noted on the side of the road behind the storm core, which was not directly penetrated. Torrential rains, 60 MPH winds, and frequent lightning were also observed with this storm. Conditions causing the storm were surface heating, a dryline, a surface trough, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was also in effect for the area until 10 PM CDT.

18). May 16, 3:30 PM - Interception and observation of a very severe and possibly tornadic thunderstorm from near Perryton in Ochiltree County, Texas and northeastward into Beaver County, Oklahoma along Highways 83 and 270. The storm was a classic supercell storm with a possible tornado observed during its early life to the northwest of Perryton, Texas. The storm produced another funnel cloud and evolved to HP mode as it entered Beaver County, Oklahoma. The core of the storm was not penetrated, but likely contained large hail and strong winds. The storm had a striking visual appearance as well, with wall cloud and RFD cut. The storm eventually evolved to a line segment and weakened after 4:30 PM. Conditions causing the storm were surface heating, a dryline / Pacific front interactions, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A PDS (particularly dangerous scenario) tornado watch was also in effect for the area until 10 PM CDT.

19). May 16, 5:30 PM - Interception, penetration and observation of an extremely severe and tornadic thunderstorm from near Wheeler, Texas in Wheeler County along Highway 83 and south to near Twitty. The storm was an HP supercell with a powerful rain wrapped tornado, and a wide (1/2 mile or so) damage path was observed along Highway 83 south of Wheeler and north of Twitty. Power poles and lines were snapped and across the road, with some debris scattered (roofing material and trees). When the storm was penetrated from the north, rapidly shifting winds (north to west) were noted on the south side of Wheeler with winds approaching 75 MPH. Dime to isolated quarter sized hail, torrential rains, and frequent lightning was also observed. The tornado was rain wrapped and despite being close to our location, not visible. One person was killed in this storm. This was the same supercell and tornado that produced the more visible tornado near McLean, Texas earlier during its classic phase. Conditions causing the storm were surface heating, a dryline, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A PDS (particularly dangerous scenario) tornado watch was also in effect for the area until 10 PM CDT.

20). May 16, 7:00 PM - Interception, penetration and observation of an extremely severe and potentially violent tornadic thunderstorm from the southwest of Elk City, Oklahoma and southeast of Erick in Becklham County and northeastward to near Thomas in Custer County along SR 152, I-40, and eventually near Highway 183. The storm was an extremely severe HP supercell storm, and produced a large and destructive tornado that caused one death and damage in Elk City, Oklahoma. We approached the storm from the west, and eventually the western circulation of the tornado itself, passing through the intense supercell core and hook region. Extremely heavy rains, and copious amounts of 2" hail, with isolated baseball and even softball sized hail smashing / bouncing across the road - With the alarming silhouette of the developing wedge tornado in front of us on SR 152! The storm also contained frequent lightning (with some close hits). Winds in this area gusted over 100 MPH, especially in rear inflow jets / RFD on the backside of the tornado. A roof and debris (from a steel building disintegrating) was observed airborne off 152 with violently shifting winds as the tornado was highly rain wrapped. Damage in Elk City also was extensive, and debris was noted falling from the sky in RFD winds southeast of there near I-40. The storm continued to the NE into Custer County, Oklahoma and weakened / evolved to a line / bow segment near dusk. Conditions causing the storm were surface heating, a dryline, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A PDS (particularly dangerous scenario) tornado watch was also in effect for the area until 10 PM CDT.

21). May 18, 3:00 PM - Interception and observation of a very severe thunderstorm from near Fargo, Oklahoma to Fort Supply in Harper County, and along SR 46 to Highways 64 and 183. The storm was a classic to HP supercell thunderstorm. A rotating wall cloud was observed with this storm, but it quickly evolved to a line segment and weakened due to storms developing south and southeast of it. Conditions encountered were heavy rains, frequent lightning, 60 MPH winds, and small hail. The main core was not penetrated. Conditions causing the storm were surface heating, a dryline, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A PDS (particularly dangerous scenario) tornado watch was also in effect for the area until 8 PM CDT.

22). May 18, 4:30 PM - Interception and penetration of a very severe and tornadic thunderstorm in Woods County, Oklahoma near Camp Houston along Highway 64. The storm was an HP supercell storm with a possible rain-wrapped tornado in progress as it was penetrated from the west. A funnel cloud developing and disappearing into rain was observed, with an area of strong rotation / dust being lofted as the weak tornado developed and lifted north (in poor visibility). Hail to 1", strong winds to 60 MPH, very heavy rains, and frequent lightning was also observed when penetrating this storm. Conditions causing the storm were surface heating, a dryline, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A PDS (particularly dangerous scenario) tornado watch was also in effect for the area until 8 PM CDT.

23). May 18, 5:15 PM - Interception and observation of an extremely severe and tornadic thunderstorm in Woods County, Oklahoma along Highway 281 and between Avard and Waynoka. The storm was a classic and cyclic supercell storm. A large cone (or even wedge tornado) was observed with this supercell looking southwest from near Avard. The tornado evolved to multi-vortex and then a large wall cloud. Another wall cloud and large funnels developed as the storm cycled. The funnel formed from the new mesocyclone while the tornado near Waynoka was still in progress. The storm also had a very striking visual appearance (with "stacked plates" presentation). This supercell evolved to LP through downscale growth and weakened northwest of Alva. The storm core was not penetrated (contained at least 2" hail), but light rains, 40 MPH winds (inflow), and frequent lightning was observed. Conditions causing the storm were surface heating, a dryline, boundary interactions, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A PDS (particularly dangerous scenario) tornado watch was also in effect for the area until 8 PM CDT.

24). May 18, 6:30 PM - Interception and observation of a severe thunderstorms from west of Custer City and near highway 183 and SR 33 west of Putnam and Arapaho in Dewey and Custer Counties. The storm was a multicell cluster of strong and severe storms, formed by two supercells evolving to HP and merging ahead of the dryline. A large funnel was observed on the forward flank of the storms west of Putnam, as well as a large shelf cloud towards the southern portion of the storm complex. The cores were not penetrated. Frequent lightning, heavy rains, and 45 MPH winds were encountered. Conditions causing the storm were surface heating, a dryline, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills. A PDS (particularly dangerous scenario) tornado watch was also in effect for the area until 8 PM CDT.

25). May 19, 1:00 PM - Observation of a very severe thunderstorm near Graham and Archer City, Texas in Archer County and along Highway 79. The storm was an elevated supercell storm at the end of a line segment of strong and severe thunderstorms. The supercell storm was HP in nature, but still north of a boundary separating rain cooled air from earlier storms to its north. The storm had an impressive shelf cloud associated with its gust front. The core (containing golfball sized hail) was not penetrated. Frequent lightning, 40 MPH winds, and light rain were encountered passing the storm. Conditions causing the storm were surface heating, outflow boundaries, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills. A tornado watch was also in effect for the area until 8 PM CDT.

26). May 19, 6:30 PM - Interception, observation, and penetration of a very severe thunderstorm west of Voss, Texas and near the CH Ivie Reservoir in Concho County and east of Highway 83. The storm was and HP supercell and part of a cluster of strong and severe thunderstorms. The storms were outflow dominant. A rotating wall cloud was also observed before the storm got undercut. The core was not directly penetrated, which contained hail at least 2". Frequent lightning (with some close hits), heavy rains, 60 MPH winds, and small hail was encountered with this storm. Conditions causing the storm were surface heating, outflow boundaries, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills. A tornado watch was also in effect for the area until 8 PM CDT.

27). May 21, 6:30 PM - Interception and observation a very severe (and possibly tornadic) thunderstorm near McAlister and House in Quay County, New Mexico near SR 206 and 156. The storm was a classic supercell storm, and several large lowerings were observed on its southern side. The storm had a large rotating wall cloud, and several funnels, one of which might have touched down as a weak tornado. The storm core (with hail at least 2") was not penetrated, and the storm was viewed from the east. Frequent lightning, light to moderate rain, and 30 MPH winds was encountered east of the storm and away from the core. The storm was over rural areas. Conditions causing the storm were surface heating, upslope wind flow, a stationary boundary, a low pressure trough, and upper trough (NW flow aloft). A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills.

28). May 22, 5:00 PM - Interception and observation a strong thunderstorm over rural areas of Roosevelt County, New Mexico and west of Highway 70 near Delphos and Portales. The storm was a small LP supercell. Conditions encountered were occasional lightning, light rains, 30 MPH winds, and hail up to penny sized. One CG lightning bolt started a grass fire in an open field after it hit. Conditions causing the storm were surface heating, upslope wind flow, a stationary boundary, a low pressure trough, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills. A severe thunderstorm watch was in effect for the area until 8 PM MDT.

29). May 22, 7:00 PM - Interception and observation a very severe thunderstorm from west of Delphos and Kenna, New Mexico in Chaves County along and near Highways 70 and 285, and ultimately eastward along Highway 380 east of Roswell. The storm was an intense LP to classic supercell storm. The storm had a very striking visual appearance during all stages of its lifecycle, including RFD, hail shafts, rock-hard updraft, and rotating high-based wall clouds. The core of the storm was not penetrated, but contained large hail to at least 2". Copious amounts of quarter sized hail was noted along Highway 380 behind the storm. Other conditions were winds over 50 MPH (with dust), light rain, and frequent lightning. Conditions causing the storm were surface heating, upslope wind flow, a stationary boundary, a low pressure trough, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills. A severe thunderstorm watch was in effect for the area until 8 PM MDT.

30). May 25, 3:30 PM - Interception and penetration of a very severe and tornadic thunderstorm from Yuma County, Colorado eastward to near Saint Frances, Kansas along Highway 36 and near Highway 385. The storm was a powerful classic to HP supercell storm. The storm core contained hail to baseball sized. Hail up to golfball sized was observed in the hook of the storm near the intersection of Highways 385 and 36. Much of this hail accumulated on the ground do a depth of a few inches. A weak tornado was observed looking eastward from Highway 385 to the northwest of Hale / Bonny Reservoir and east of Idalia. The tornado was weak, lasted roughly 5 minutes, and remained over an open field. A rotating wall cloud was observed exiting the storm core to the northeast later. The storm also contained 65 MPH winds, torrential rains, and frequent lightning. The storm also had a striking visual appearance, with the base resembling a "cinnamon roll" and the weak tornado under it. Conditions causing the storm were surface heating, upslope wind flow, a stationary boundary, a low pressure lee trough, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was in effect for the area until 9 PM MDT (10 PM CDT).

31). May 25, 6:30 PM - Interception and penetration of a very severe and possibly tornadic thunderstorm from near Colby, Kansas along I-70 and southeastward to near Trego Center south of Wakeeney near Highway 283 in Gove and Trego Counties. The storm was an HP supercell storm. A possible tornado occurred with this storm near Oakley, but was rain wrapped and not visible. Strong winds gusting over 80 MPH were encountered east of Oakley on I-70. Torrential rains, quarter sized hail, and frequent lightning with close hits was also observed. Power poles were snapped and some structural damage occurred near Oakley. Flying tree debris was also noted blowing across I-70. Once east of the storm, before being undercut by outflow, the storm had a striated inflow appearance and large wall cloud with RFD clear slot on its southern side before weakening. Conditions causing the storm were surface heating, upslope wind flow, boundary interactions, a low pressure lee trough, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was in effect for the area until 10 PM CDT.

32). May 26, 5:30 PM - Observation and penetration of a very severe and possibly tornadic thunderstorm from Arapahoe county near Byers, Colorado via I-70 and Highway 36, then eastward through Washington and Yuma Counties to near Idalia, then eventually (via Highways 36, 385, and I-70) into Kansas near Goodland in Sherman County. The storm was a classic to HP supercell storm. Several penetrations were made on the storm, including a hook slice into the "bear's cage" north of Anton, Colorado. Very large hail, with numerous 2" (and possibly to tennis ball sized) was encountered with this storm. Heavy rains, 60 MPH winds, and frequent lightning were also encountered. A possible tornado was reported near Idalia, but it was low contrast and not visible from my vantage point. The storm had a very striking visual appearance, with striations, RFD cut with funnels, and dramatic "stacked plates" appearance. Conditions causing the storm were surface heating, upslope wind flow, boundary interactions, a low pressure lee trough, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was in effect for the area until 8 PM MDT (9 PM CDT).

33). May 27, 7:00 PM - Observation and penetration of a very severe and thunderstorm from near Pawhuska in Osage County, Oklahoma, eastward along Highway 60 through Nowata and Washington County to near Adair. The storm was a classic supercell that evolved to HP, then weakened to a line segment. A wall cloud was observed with the storm early in its life, with a striated "barber pole" updraft. Hail to 2" was encountered while going through the core of the storm near Nowata. The storm also contained frequent lightning (with some close hits), heavy rains, and 50 MPH winds were also encountered. Conditions causing the storm were surface heating, upslope wind flow, dryline / boundary interactions, a low pressure area, and upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was in effect for the area until 12 AM CDT (the following day).

34). June 12, 4:00 PM - Interception, indirect penetration, and observation of an extremely severe and tornadic thunderstorm in Goshen County, Wyoming near Fort Laramie, along Highways 26 and 85. The storm was a classic to HP cyclic supercell storm. A large rotating wall cloud and striking visual appearance was observed with this supercell, along with a few tornadoes (one a significant stove-pipe type) observed west of Highway 85. The tornadoes were not highly visible. The storm also contained grapefruit sized hail, frequent lightning, heavy rains, and 60 MPH winds. The core was not directly penetrated, and hail to golfball sized was encountered near Fort Laramie. Little damage was noted as the storm remained over open country. Conditions causing the storm were upslope wind flow, a low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A PDS (particularly dangerous situation) tornado watch was also in effect for the area until 8 PM MDT (9 PM CDT).

35). June 12, 6:30 PM - Interception, indirect penetration, and observation of an extremely severe and tornadic thunderstorm in Banner County, Nebraska near Harrisburg, along SR 71 south and SR 88 east. The storm was a cyclic supercell storm that had a long history of producing significant tornadoes (along a swath from NE Colorado and into Nebraska). The final tornado this storm produced was observed while heading south on SR 71 north of Harrisburg. The storm evolved to HP mode after this, with an impressive visual appearance. The core was indirectly penetrated, and quarter sized hail, 60 MPH wind gusts, heavy rain, and frequent lightning was encountered. The storm contained grapefruit sized hail in its core earlier, and one of the tornadoes destroyed a house. Conditions causing the storm were upslope wind flow, a low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A PDS (particularly dangerous situation) tornado watch was also in effect for the area until 8 PM MDT (9 PM CDT).

36). June 13, 5:00 PM - Interception and penetration of a very severe and tornadic thunderstorm southwest of Plankington, South Dakota in Aurora County, and from near CR 23 to I-90 and near 281 to the north and east. The storm was an HP supercell storm. A large gustnado was observed with this storm as it was near I-90 and before it became outflow dominant. Strong winds to 60 MPH, frequent lightning, quarter sized hail, and heavy rains were also encountered with this storm. Conditions causing the storm were a dryline / Pacific cold front, a low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was also in effect for the area until 10 PM CDT.

37). June 13, 5:30 PM - Interception and penetration of a very severe and possibly tornadic thunderstorm from near Stickney, South Dakota in Aurora County to Davison County and near Mitchell, and from Highway 281 to SR 37 via I-90 east. The storm was an intense HP supercell storm with very strong rotation as it was being undercut (again) by outflow. A rotating area with tagging rain curtains was observed near Stickney. The storm also contained quarter sized hail, frequent lightning, 65 MPH winds, and torrential rains. The storm evolved to a line segment, and this was followed as far south as Alexandria near SR 25. Conditions causing the storm were a dryline / Pacific cold front, a low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A tornado watch was also in effect for the area until 10 PM CDT.

38). June 13, 8:30 PM - Penetration of a very severe thunderstorm from near Bow Valley, Nebraska in Cedar County, along SR 57. The storm was a line segment of strong and severe thunderstorms. An intense portion of the line was penetrated when back-tracking due to road construction and the area coned off by SR 12. Extremely heavy rains, frequent lightning, heavy and thick hail to 1" (quarter sized) covering the ground, and winds gusting over 70 MPH. Trees were downed along side the vehicle, with a portion of the tree striking the vehicle and breaking off the HAM radio antenna. The storm caused tree damage and power out in many areas as it continued southeastward through Sioux City. This made finding a hotel there very difficult due to wind damage. Conditions causing the storms were a dryline / Pacific cold front, a low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was also in effect for the area until 1 AM CDT the following day.

39). June 14, 5:00 PM - Observation and penetration of a severe thunderstorm near Hunnewell, Missouri in Marion County near Highway 36, and southward along SR V to near Highway 24 and Stoutsville. The storm was an HP supercell storm that evolved to a line segment after being undercut by strong outflow. An RFD clear slot, rotating wall cloud, and funnel was also observed with this storm during its early stages. Heavy rains, 60 MPH winds, and frequent lightning was also encountered. Conditions causing the storm were a stationary front / outflow boundary, a low pressure trough, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills. A severe thunderstorm watch was also in effect for the area until 8 PM CDT.

40). June 15, 5:00 PM - Interception, observation, and direct penetration of a very severe and tornadic thunderstorm near Lacross, Kansas in Rush County to near Great Bend in Barton County, and along highways 28 / 281 to near Highway 56. The storm was a supercell storm that initiated earlier west of Russell, Kansas. A rotating wall cloud, or even a brief tornado was observed when this storm was first encountered during its early stages and before it split. Later the main southern split was directly penetrated while caravanning with other chaser Dan Shaw and Don Sanderson to report hail sizes. During the core penetrations of the supercell, large amounts of golfball sized hail, with larger 2" (and even one stone to 2.5" baseball sized) also observed. Winds up to 45 MPH, frequent lightning, and heavy rains were also encountered. A wall cloud and RFD was also noted with this storm. Conditions causing the storm were a stationary front and dryline "triple point", a low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills, audio, and HD video. A severe thunderstorm watch was also in effect for the area until 7 PM CDT.

41). June 15, 7:00 PM - Observation and penetration of a severe thunderstorm near Saint John, Kansas in Stafford County along highways 50 and 281. The storm was a supercell storm that started as a classic / HP storm, then evolved to a multicell cluster of strong and severe storms near Pratt, Kansas. I was caravanning with chaser Dan Shaw and Don Sanderson on this storm. Hail up to 2", 65 MPH winds, heavy rains, and frequent lightning were all encountered in this storm. At dusk, north of Pratt, and incredible display of mammatus was also observed from SR 61 while Dan gave me a spare antenna to replace the broken one I had. Conditions causing the storm were a stationary front and dryline "triple point", a low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was also in effect for the area until 2 AM CDT the following day.

42). June 16, 5:00 PM - Interception, observation, and penetration of a very severe and tornadic thunderstorm near Madison, Nebraska in Madison County near Highway 81 and SR 91, and southeastward to near Schuyler in Colfax County and Highway 30 off SR 15. The storm was an HP supercell storm. A possible brief tornado was barely visible early in the storms life cycle near Madison, before intense rain wrap ensued. Winds gusting near 70 MPH, frequent lightning, torrential rains, and small hail was encountered. The storm became outflow dominant near Schuyler. Conditions causing the storm were a dryline, low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was also in effect for the area until 10 PM CDT.

43). June 16, 7:30 PM - Observation and penetration of extremely severe thunderstorms from near Columbus, Nebraska in Platte County, and southeastward past Saline County to the SW of Lincoln, and through the Beatrice area in Gage County. The storm was followed via SR 15 out of Columbus to SR 33 / 103 to near Beatrice, and Highway 77 back into Kansas to north of Manhattan in Riley County! The initial stage of this storm complex was an HP supercell near Columbus that became outflow dominant and pushed rapidly southeastward thereafter. The storm merged with an LP supercell storm west of Lincoln, briefly producing funnel clouds. The storm complex, now with an embedded mesocyclone, continued southeastward towards Gage County after dusk, with extreme-damaging (derecho / XDW) winds exceeding 100 MPH. The strongest winds encountered with this system were about 70 MPH. Numerous trees down, wind damage, and power poles snapped were observed near Beatrice, making getting through there nearly impossible. Hail to quarter sized, torrential rains, and CONTINUOUS lightning (many close hits as well) were also encountered. At times the lightning was so frequent (more than 10 flashes per second), that if you turned off your headlights you could still see clearly, as if you were in a nightclub. Flash flooding and wind damage was observed in Beatrice, with power out in most areas. Conditions causing the storm were a dryline / outflow boundary interactions, low pressure area, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was also in effect for the area until 10 PM CDT.

44). June 17, 7:00 PM - Interception and observation of a severe thunderstorm near Memphis, Missouri in Scotland County, along and near SR 15 and Highway 136. The storm was initially an HP supercell storm, but became outflow dominant and evolved to a cluster of storms as it spread southeastward to near Williamstown. The core of the storm was not penetrated, but contained hail up to baseball sized. Conditions encountered were 60 MPH wind gusts, heavy rain, small hail, and frequent lightning. Downed trees blocked some roads, and I used the vehicle mounted winch to clear a tree off SR A to allow passage. Power was also out in some areas. Conditions causing the storm were a stationary front / outflow boundary, a low pressure trough, surface heating, and an upper trough. A 2016 Jeep Wrangler was used to chase the storms. Documentation was digital stills and HD video. A severe thunderstorm watch was also in effect for the area until 1 AM CDT the following day.

This concludes the chase log for the central US Plains for the main chase "expedition" of 2017 starting April 17 and ending on June 26. The summary includes a total of 44 observations, out of which there were 42 severe thunderstorms and 2 strong thunderstorms. Out of these thunderstorms, as many as 21 tornadoes were observed, with at least 6 of them being significant and / or destructive. The main chase vehicle conducting this chase was a 2016 Jeep Wrangler. All entries for the logs above are for the local time zone unless otherwise noted. This information was prepared exclusively for the National Weather service and the team of Skywarn storm spotters.