Tropical Storm Calvin brought gusty winds and rain to Hawaii on Wednesday. At 8:00 a.m. EDT on Wednesday the center of Tropical Storm Calvin was located at latitude 17.7°N and longitude 155.6°W which put it about 160 miles (260 km) south of Hilo, Hawaii. Calvin was moving toward the west at 20 m.p.h. (32 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 1003 mb.

A Tropical Storm Warning was in effect for Hawaii County.

After Tropical Storm Calvin strengthened late on Tuesday, it started to weaken again on Wednesday morning. An upper level trough northwest of Hawaii was producing southwesterly winds that were blowing toward the top of Calvin’s circulation. There were strong easterly winds in the lower levels of the atmosphere. The combination of southwesterly winds in the upper troposphere and easterly winds in the lower levels of the atmosphere caused strong vertical wind shear. The winds in the upper troposphere blew the top part of Tropical Storm Calvin toward the northeast. The strong easterly winds near the surface pushed the lower part of Calvin quickly toward the west.

The strong vertical wind shear caused Tropical Storm Calvin to weaken on Wednesday morning. The center of Calvin at the surface was passing south of the Big Island of Hawaii. Bands revolving around the center at the surface consisted primarily of showers and lower clouds. Thunderstorms were occurring in bands in the northern side of Tropical Storm Calvin where the wind was pushing air up the eastern slopes of the Hawaiian Islands. Winds to tropical storm force extended out 140 miles (220 km) in the northern side of Calvin’s circulation. Winds in the southern part of Calvin were blowing at less than tropical storm force.

Tropical Storm Calvin will move through an environment unfavorable for intensification during the next 24 hours. Calvin will move over water where the Sea Surface Temperatures are near 26˚C. However, the upper level trough northwest of Hawaii will continue to cause strong vertical wind shear. Tropical Storm Calvin will weaken to a tropical depression during the next 24 hours.

Tropical Storm Calvin will continue to produce gusty winds and locally heavy rain in Hawaii during the next 24 hours. The strongest wind gusts will occur at higher elevations. Calvin could cause isolated minor wind damage. Locally heavy rain could cause flooding in some locations. Flood Watches are in effect for the Big Island of Hawaii, Maui, Molokai, Lanai, and Kahoolawe.