Tropical Storm Calvin sped toward Hawaii on Tuesday. At 2:00 p.m. EDT on Tuesday the center of Tropical Storm Calvin was located at latitude 17.6°N and longitude 150.5°W which put it about 330 miles (640 km) east-southeast of Hilo, Hawaii. Calvin was moving toward the west at 22 m.p.h. (35 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1002 mb.

A Tropical Storm Warning was in effect for Hawaii County.

Tropical Storm Calvin appeared to be getting stronger on Tuesday afternoon. More thunderstorms formed near the center of Calvin’s circulation. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Even though Tropical Storm Calvin appeared to be strengthening, the vertical structure of Calvin’s circulation seemed to tilt a little to the north in the middle and upper levels of the troposphere. Winds to tropical storm force extended out 105 miles (165 km) in the northern side of Tropical Storm Calvin. Winds to tropical storm force extended out 25 miles (40 km) in the southern side of Calvin.

Tropical Storm Calvin will move through an environment that will be somewhat favorable for intensification during the next 24 hours. Calvin will move over water where the Sea Surface Temperatures will increase to 26˚C. It will move through a region where the upper level winds are blowing from the south. Those winds are not very strong, but they will cause some vertical wind shear. Tropical Storm Calvin could strengthen during the next 24 hours in spite of the vertical wind shear.

Tropical Storm Calvin will move around the southern part of a subtropical high pressure system over the Eastern and Central Pacific Ocean. The high pressure system will steer Calvin toward the west during the next several days. On its anticipated track, Tropical Storm Calvin will move near the Big Island of Hawaii on Tuesday night. Calvin will bring gusty winds and locally heavy rain to Hawaii on Tuesday night and Wednesday. Flood Watches are in effect for the Big Island of Hawaii, Maui, Molokai, Lanai, and Kahoolawe.