Tornado outbreak of April 1-2, 2017

This was a significant, but localized, tornado outbreak that occurred in Eastern TN on April 1 extending into April 2. Multiple strong, long tracked tornadoes developed across the area resulting in several dozen fatalities and injuries. This was the deadliest tornado outbreak in TN history, along with costliest. Several cities in TN were hit by strong-violent tornadoes including; Knoxville, Crossville, Newport, Sevierville, Pigeon Forge, Maryville, Acola. 74 tornadoes in total occured in this outbreak, with 30 being strong and 6 being violent.

Synposis
On March 29, the SPC highlighted an Enhanced risk for severe weather across areas of Eastern TN and Southeastern KY. On March 30, this area was upgraded to a Moderate risk with the SPC indicating a localized, but dangerous tornado outbreak was possible for these areas. On the morning of April 1, the SPC upgraded to a rare high risk for a small portion of Eastern TN. This included a 30% hatched area for areas sorrounding Knoxville, TN. Dewpoints in the mid to upper 70s were fueled up into the valley. Very strong wind shear was also present along with a jetstreak. A low pressure was centered over Indiana at 984 MB at 12z April 1st. At 18z, the SPC issued a rare PDS tornado watch for almost the entire Eastern TN area, with probalities of >95%/90%. At 19z, supercells began to fire along a rare dryline east of Nashville. Many of these supercells would track all the way into the Western NC mountainside.

