Powerful Lane Approaches Hawaii

The Hawaiian Islands are blessed in many ways and from a meteorological perspective, they are fortunate to sit in the central Pacific where the frequency of tropical cyclones (e.g., hurricanes, typhoons) is relatively low compared to that found in the eastern and western Pacific. 

Historical tropical cyclone tracks (Source: https://coast.noaa.gov/hurricanes/)

One reason for this is that the sea surface temperatures in the central Pacific are climatologically lower than those found at similar latitudes in the tropical eastern and western Pacific Ocean.  Hawaii also benefits from a protrusion of cooler sea surface temperatures to its east and south which, combined with climatological atmospheric circulations, often steers tropical cyclones to the south.  

Source: Climate Prediction Center

There are, however, exceptions.  The images below illustrate the tropical storms and hurricanes passing within 200 (top) and 75 miles (bottom) of the Hawaiian Islands since 1950.  Hurricane landfalls in which the low center crosses the coast of an island while at hurricane force are rare and since 1950 consist of Dot (1959) and Iniki (1992), both of which passed over Kauai, Dot as a category 1 hurricane and Iniki as a category 4.  Other tropical cyclones storms have weakened to below hurricane force or passed near the islands.  Note that impacts extend from the low center, so landfall is not necessary for a tropical storm or cyclone to bring hazardous and high impact weather to the island.  

Source: Central Pacific Hurricane Center

As I write this at approximately 8 AM MDT Wednesday 22 Aug, Hurricane Lane is a very powerful storm approximately 300 miles south of the Island of Hawaii, with a very well formed high and compact, symmetrical cloud shield.  

Source: NOAA/NESDIS

The 2 AM HST advisory issued by the Central Pacific Hurricane Center reports that Lane is a category 5 hurricane with maximum sustained winds near 160 mph, with higher gusts.  Aircraft penetration into Lane show the remarkable drop of estimated sea level pressure as the Air Force Hurricane Hunter traversed the hurricane (red line, upper left), with an estimated minimum sea-level pressure just below 935 mb, which is the atmospheric pressure one typically finds at about 650 m (2100 feet) above sea level.  So, moving into the center of Lane at a constant altitude results in a drop in pressure similar to that if you were to climb from sea level to 2100 feet. 

Source: Levi Cowan - tropicaltidbits.com

Remotely sensed wind speeds are presented at upper right and shows the rapid increase in speed as the aircraft approaches the eyewall, the relative calm of the eye, and then a second max as it exited the eye and traversed the eyewall again.  At present, Lane is a very compact system with hurricane-force winds extending 40 miles from the center.  

Lane will likely remain a hurricane, possibly a major one (i.e., category 3 or greater) as it approaches the Hawaiian Islands. The cone below, issued at 11 PM HST Tuesday, illustrates the region that will likely contain the probable path of the storm, illustrating the possibility of a track very near one or more of the Hawaiian Islands, or somewhat further offshore.  A track traversing one or more of the islands remains possible (note that the tropical cyclone track is within this cone about 2/3 of the time, so there is a low probability possibility that Lane's track is outside it), although landfall is not needed for major impacts to be felt by the islands as a track just off the west coast of Hawaii, for example, would likely result in the strong winds and heavy precipitation accompanying and surrounding the eyewall moving over the island.  Hurricane warnings currently cover the Island of Hawaii, with watches for Maui, Lanai, Molokai, Kahoolawe, and Oahu.  

Source: Central Pacific Hurricane Center

The latest advisories and information are available at the Central Pacific Hurricane Center web site from the National Weather Service.  Hurricane impacts include not only wind, but also surf, surge, and rainfall and related flooding that can occur even if there is not a direct landfall.  The National Weather Service and emergency management agencies are your best sources of information prior to and during this and other storms.