Life-cycle of Tropical Storm Erin (2007)

On 8 August 2007, a mesoscale region of deep, moist convection (DMC) and attendant low-level cyclonic vorticity developed over northern South America and tracked in a general northwestward direction to just south of Cuba by 13 August. This antecedent mesoscale region of DMC and associated low-level cyclonic vorticity subsequently organized into Tropical Storm (TS) Erin over the Gulf of Mexico by 15 August, making landfall along the Texas coast on 1200 UTC 16 August with surface winds near 35–40 knots. Although weak at the time of landfall, TS Erin made an impact on the daily weather from Texas to the northern Great Plains, and to the eastern United States (US) during the post-landfall period of 16–22 August. In particular, TS Erin was noteworthy for: (1) producing widespread rains > 150 mm over Texas, Oklahoma, and Missouri during 16–19 August, (2) briefly reintensifying to TS strength over Oklahoma during 0000–1200 UTC 19 August, (3) contributing to a predecessor rain event (PRE) over the northern Great Plains and Great Lakes region on 19–20 August, (4) producing widespread rains > 25 mm over Kentucky on 21 August, and (5) triggering a severe weather outbreak over North Carolina and Virginia on 21–22 August.

The purpose of this presentation is to document the life-cycle of TS Erin from its initial development over the Gulf of Mexico, to the severe weather outbreak associated with the remnants of Erin over North Carolina and Virginia. Dynamic tropopause analyses will be used to document to evolution of the large-scale pattern, and diagnose the synoptic-scale contribution to the life-cycle of TS Erin. In particular, precipitable water analyses and air parcel trajectories will be used to show the contribution of deep tropical moisture from TS Erin to the 19 August PRE. Given that the remnants of TS Erin retriggered episodes of convection over successive days after landfall, comparisons will be made between the structure of TS Erin and continental long-lived mesoscale convective vortices.