Halola — 2015

Halola formed from a disturbance in a long-lived monsoon trough in early July 2015. A broad low-level circulation became better defined by 9 July, and the system was designated a tropical depression about 890 nautical miles southwest of Honolulu at 0600 UTC 10 July. It moved generally westward, strengthened into Tropical Storm Halola by 0000 UTC 11 July, and continued west-northwest before crossing the International Date Line just before 0000 UTC 13 July, after which it moved into the western Pacific basin and is not covered further in this report. Halola did not make any landfalls while it was in the Central Pacific Hurricane Center’s area of responsibility (east of the International Date Line). The storm remained over open ocean during the period covered here (10–12 July 2015) and exited the CPHC area before any interaction with land. The maximum intensity while Halola was in the CPHC area was 50 knots (about 58 mph) with a minimum central pressure of 998 mb. That intensity corresponds to a moderate tropical storm on the Saffir–Simpson scale; Halola later reached typhoon strength after moving west of the International Date Line (outside the CPHC report’s area). There were no reports of storm surge or rainfall effects attributed to Halola in the CPHC area of responsibility. No ship reports of tropical-storm-force winds were received while the system was east of the International Date Line. No damage or casualties were reported in association with Halola during the portion of its life covered by this report. The regions nearest to its track while in the central Pacific (open waters south-southwest of Hawaii) experienced no reported impacts. Noteworthy items: Halola formed nearly simultaneously with Tropical Storm Iune, making them the earliest known tropical cyclones to form during a central Pacific hurricane season at that time and contributing to the very active 2015 central Pacific season. CPHC genesis forecasts identified the disturbance up to 138 hours before formation, and official intensity forecasts for Halola were quite accurate (average errors below 5 kt), while track forecast errors were somewhat larger than the recent 5-year mean.