ZCZC HFOTCDCP2 ALL TTAA00 PHFO DDHHMM Hurricane Lane Discussion Number 27 NWS Central Pacific Hurricane Center Honolulu HI EP142018 500 AM HST Tue Aug 21 2018 Lane remains a powerful hurricane this morning, with a well- developed warm eye completely surrounded by persistent cold cloud tops. Subjective Dvorak current intensity estimates were a unanimous 6.5/127 kt while ADT was in relative agreement. The initial intensity for this advisory remains at 130 kt as Lane's satellite signature has changed little since last sampled by Hurricane Hunters and the NOAA P-3 Monday evening. The initial motion for this advisory is 275/10 kt, with Lane continuing to be steered by a mid-level ridge to the north. Over the next day or two, Lane is expected to reach the western periphery of the ridge, and into an area of relatively light steering flow. This is expected to allow the cyclone to gain latitude as its forward speed diminishes. In this scenario, Lane will begin to make a gradual turn to the west-northwest on Wednesday, with a more decided turn toward the northwest on Thursday. After this point, the track and intensity forecast become increasingly uncertain, as a bulk of the model guidance is depicting interaction between Lane and the terrain of the islands. This interaction then leads to a weakened Lane increasingly being steered by the low-level trade wind flow. The updated track forecast is essentially an update of the previous official forecast, and lies very close to the multi-model consensus HCCA. Water temperatures along the forecast track will be sufficiently warm to support a major hurricane, and thus any significant weakening before Lane draws closer to the Hawaiian Islands will likely be due to shear. In the short-term, shear is expected to remain light, and subtle intensity fluctuations associated with inner-core dynamics will likely lead to little overall change in intensity. By 72 hours, the forecast anticipates an increase in shear as Lane lies between the ridge to the east and a trough aloft to the northwest of the main Hawaiian Islands. The updated intensity forecast is close to the previous, and although it is on the higher end of the guidance envelope, it closely follows the trends presented by the multi-model consensus IVCN. In addition to an increasing number of storm penetrations by the Hurricane Hunters of the 53rd Weather Reconnaissance, the NOAA G-IV will once again be sampling the larger scale environment to help forecast models better initialize. The NOAA P-3 mission slated for this morning has been scrapped as the aircraft needs to be examined after encountering strong turbulence last night. KEY MESSAGES: 1. Lane is forecast to move dangerously close to the main Hawaiian Islands as a hurricane later this week, potentially bringing damaging winds and life-threatening flash flooding from heavy rainfall. As Lane is expected to be slow-moving as it nears the islands, it will produce large and damaging surf, mainly along exposed south and west facing shores. A Hurricane Watch has been issued for Hawaii and Maui counties, and additional Tropical Storm or Hurricane Watches may be required later today or tonight. 2. It is much too early to confidently determine which, if any, of the main Hawaiian Islands will be directly impacted by Lane. Even if the center of Lane were to remain offshore, it is important to remember that impacts from a hurricane can extend well away from the center. Interests throughout Hawaii are urged to closely monitor the progress of Lane the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 21/1500Z 14.1N 152.3W 130 KT 150 MPH 12H 22/0000Z 14.4N 153.4W 125 KT 145 MPH 24H 22/1200Z 15.0N 154.6W 120 KT 140 MPH 36H 23/0000Z 15.9N 155.6W 110 KT 125 MPH 48H 23/1200Z 17.0N 156.5W 100 KT 115 MPH 72H 24/1200Z 19.7N 157.6W 85 KT 100 MPH 96H 25/1200Z 21.5N 159.5W 65 KT 75 MPH 120H 26/1200Z 21.5N 163.0W 50 KT 60 MPH $$ Forecaster Birchard NNNN