Tropical Storm Lowell (2008) - Meteorological History

Meteorological History

The origin of Lowell began from a tropical wave that moved off Africa. The northern portion of the wave would form into Hurricane Hanna in the Atlantic. The southern portion of the wave separated and continued to move westward across the Caribbean and crossed Central America during August 27 and August 28.Later a trough with a weak low pressure area developed over southern Mexico, The area of low pressure was found embedded within a large area of scattered moderate and isolated strong convection. The initial low failed to develop for the but new low formed on western side of the trough. A larger cyclonic circulation associated with the trough and induced a gradual increase in deep convection. The low level convection center was temporarily displaced from the convection, and a smaller embedded circulation developed and was eventually detached from the larger circulation. It is estimated that a tropical depression formed at 1200 UTC 6 September when it was centered about 310 mi (500 km) south of Manzanillo, Mexico.

As convective banding formed, the depression gradually intensified and was upgraded a Tropical Storm Lowell six hours later. A deep-layer anticyclone over Mexico steered Lowell northwestward until September 8. However, strong upper-level winds on the south side of the anticyclone produced strong northeasterly to easterly wind shear over the tropical cyclone for several days. Due to the shear, the low level convection became exposed and sheared. despite this, Lowell slowly strengthened and reached a peak intensity of 50 mph (85 km/h), it then passed near Socorro Island without any known damages. The shear had lessened over the system, but with stable and dry air, the storm begin to weaken. Lowell moved towards north and northeast due to a subtropical ridge northwest of the system. It downgraded to a tropical depression at 0600 UTC 10 September as it was moving north-northeastward about 259 mi (417 km) west-southwest of the southern tip of Baja California. Thunderstorm activity near the center had increased slightly on 10 September. The circulation began to slowly spin down as it made landfall around Cabo San Lucas, Mexico at 0900 UTC 11 September. As it made landfall the mid to upper level winds left the low level center exposed form the thunderstorm activity. Lowell degenerated into an elongated surface trough that extended across the southern Gulf of California. It followed a squall line and a frontal boundary and quickly dissipated. The remnant low produced rain across Northwestern Mexico, it later joined Hurricane Ike and caused damage further inland.