05-18-10 CHASE LOG: TX

This was a Moderate Risk day from eastern CO southward through western TX with good promise of producing tornadoes, fairly well forecast several days in advance.I was driving for Silver Lining Tours and this was Day 1 so we wanted to get a good chase in right away.The tour group flew into Oklahoma City, OK the day before and we left there in the morning to target Dalhart, TX for late afternoon initiation.There was an upper level trough that was starting to move out into the High Plains late on the 18th and a low pressure system had been developing through the day across northeast CO.This system had already produced a few strong supercells that were already tornado warned across eastern CO by mid afternoon.The one concern in our area was the limited moisture as dewpoints were only in the upper 50’s, and that this would lead to high cloud bases and more of a damaging wind threat and limited tornado threat, even with decent low level shear.As the dryline began to mix out of the Rockies and the backed, southeast surface winds began to increase and become sustained at near 20 kts by the afternoon, convergence ahead of the dryline began to significantly increase and led to intense development of a storm shortly after 4pm only around 10-15 miles southwest of Dalhart where we were already in place.This storm quickly had 55,000 foot tops and went severe with very large hail rather quickly as we intercepted.Right away the storm produced a large, rotating wall cloud near Hartley, TX but we became blocked from getting ahead of the storm due to the baseball sized hail that was falling out of the core and blocking our east route.We waited behind the supercell southwest of Hartley at this point until the core had passed and then we progressed east on Hwy 87 towards Dumas.Upon moving through Dumas and then due east on Hwy 152 towards Stinnett, the storm produced 3 very brief and weak tornadoes.I was not able to get pictures or video of the first 3 tornadoes of the day as I was driving the vehicle.This storm did have some of the most amazing structure of any storm so far this year and was truly a sight to see as we followed the very slow moving storm due east.Near Stinnett the storm began to produce a huge mesocyclone and this is where we saw a stovepipe tornado just to the northwest of town.Thereafter, the storm began to lose organization and it was getting dark so this was the end of the chase day.Definitely a good way to start a 10 day storm chasing trip!