From August 22-26, 2018, Hurricane Lane impacted the Hawaiian Islands. The Joint Typhoon Warning Center coordinated with the Central Pacific Hurricane Center, NOAA and Air Force Reserve Hurricane Hunter units to provide up-to-date forecast and analysis information to the many DoD assets in Hawaii. As Hurricane Lane approached, it reached Category V on the Saffir-Simpson hurricane intensity scale, with maximum winds of 140 kts. It was forecast to approach Oahu from the south then make a sharp left turn and move westward, away from the islands. It was forecast to bring sustained winds in excess of 50 kts to Oahu, home to U.S. Indo-Pacific Command and many bases and assets, including Arleigh Burke-class destroyers, Los Angeles-class submarines, F-22 Raptors, M/V-22 Ospreys, and others. Tropical Cyclone Condition of Readiness (TCCOR) One was set on Friday, August 24, and lifted that same day as Hurricane Lane stalled west of the Big Island of Hawaii and weakened more rapidly than anticipated.

When a storm moves west of the 140W longitude line, the Central Pacific Hurricane Center (CPHC) assumes responsibility for locating the tropical cyclone, estimating its intensity, and issuing forecasts for civilians in the Hawaiian Islands. The Joint Typhoon Warning Center (JTWC) in Pearl Harbor, HI, retransmits the CPHC warnings and provides center and intensity fixes. JTWC remained in constant contact with CPHC regarding the fixes and forecasts for Hurricane Lane, discussing recent satellite imagery, the latest numerical model guidance trends, and the implications for Hawaii. JTWC also conducted teleconferences with 11 bases in the Hawaiian Islands, ensuring METOC and emergency management personnel across all services had the most updated and relevant information to make resource protection decisions, including sorting assets and setting Tropical Cyclone Condition of Readiness One on Hawaiian bases. While at TCCOR One, JTWC personnel continued to man their watch floor on generator power, issuing forecasts and coordinating resource protection for Hurricane Lane as well as three other concurrent tropical cyclones- Typhoon Soulik, impacting the Korean Peninsula, Typhoon Cimaron, impacting Japan, and Tropical Cyclone 24W, near Taiwan.

While the storm approached, the NOAA and Air Force Reserve Hurricane Hunters flew sorties into Hurricane Lane, releasing dropsondes into and around the storm from Gulfstream IV-SP and Lockheed WP-3D Orion aircraft, gathering in-situ data for real-time verification of structure and intensity. Hurricane Hunter data is also ingested into numerical weather models, improving the model’s forecast accuracy. Several JTWC personnel flew aboard the NOAA WP-3D Orion aircraft as it circled and penetrated Hurricane Lane to gather data.

Oahu itself experienced minimal impacts from Hurricane Lane, limited to rockfalls on highways and power outages. Several surface vessels and submarines, as well as 25 aircraft, were sortied in advance of the storm from Joint Base Pearl Harbor-Hickam. Other islands were more severely impacted- locations on the Big Island of Hawaii recorded 50” of rain, the second highest rainfall total from a tropical cyclone in U.S. history, and experienced devastating flash flooding. Stations in Maui recorded above 15” of rain with accompanying flash flooding, and gusty winds in dry vegetation fanned a wildfire near Lahaina, Maui, that forced 100 evacuations and burnt more than 10 structures and many vehicles in the resort town.

Hurricane Lane was a flagship example of coordination between civilian and military meteorology and emergency management personnel, where the expertise of the analysts and forecasters at JTWC and CPHC combined to produce the most accurate forecasts possible. Frequent and responsive communication between meteorology personnel in the different services and on different bases enabled maximum disaster preparedness in the Hawaiian Islands. 

JTWC (Task Element 80.7.7.1) is jointly staffed by U.S. Navy and Air Force personnel and falls under the operational control of Commander, Task Group 80.7/Commander, Naval Meteorology and Oceanography Command via Fleet Weather Center San Diego (Task Unit 80.7.7). U.S. Air Force personnel are administratively assigned to the 17th Operational Weather Squadron, a subordinate squadron of the 1st Weather Group and the 557th Weather Wing.

JTWC provides tropical cyclone reconnaissance, forecast, warning and decision support services for operational advantage to U.S. government agencies operating in the Pacific and Indian Oceans. Navy personnel at JTWC also provide tsunami advisory information and recommendations to shore installations and units, as well as impact forecasts for U.S. Pacific Fleet’s airborne Intelligence, Surveillance and Reconnaissance and decision support services to U.S. Pacific Command and its subordinate commands.