Hurricane Lane to strengthen south of Hawaii while generating large swells

By Alex Sosnowski, AccuWeather senior meteorologist

August 17, 2018, 2:17:00 PM EDT

In the distant footsteps of Hurricane Hector, Hurricane Lane is forecast to experience a similar evolution and take a similar path just south of the Big Island of Hawaii next week.

Hurricane Hector reached Category 4 status but passed well south of Hawaii during early August.

The size and orientation of Lane's wind field, as well as exactly how far to the south Lane passes the islands, will determine the extent of impacts.

"At this time, we expect the center of Lane to pass about 200 miles south of the southernmost tip of the Big Island Tuesday evening Hawaii time," according to AccuWeather Hurricane Expert Dan Kottlowski.

This animation shows Hurricane Lane spinning westward over the southwestern portion of the images on Friday, Aug. 17, 2018. Hawaii is to the west of the image. (NOAA/Satellite)

"Based on that track, impacts on at least the Big Island will not be much different than that was experienced with Hector two weeks earlier," Kottlowski said.

The first impact on the waters surrounding the islands will be large swells spreading westward and northward later this weekend into next week.

Conditions can become dangerous for ocean vessels south of the islands as well as small craft attempting to navigate the inter-island channels next week.

Surf may become too rough and dangerous for most bathers and boarders along the south- and east-facing beaches of the islands by next week.

Breezy conditions with showers and gusty squalls are most likely on the southern and eastern part of the Big Island, but they may spread to the middle and western islands in the String of Pearls by the middle of next week.

"Lane is moving through a belt of warm water and is likely to remain within a zone of low wind shear and sufficiently moist air," Kottlowski said, adding that these are factors that favor strengthening.

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Wind shear is the increase in wind speed at increasing height in the atmosphere and/or the increase in straight-line wind speed over horizontal distance.

"Lane is likely to soon become a major hurricane and then maintain that status for several days while approaching Hawaii," Kottlowski said.

Download the free AccuWeather app for the latest forecast and bulletins on Hurricane Lane.

Every hurricane, no matter how similar in strength, has some unique characteristics in size and shape. This is due to other weather systems in the nearby region as well as the extent of dry versus moist air and wind shear surrounding the hurricane.

If Lane becomes a compact hurricane and keeps its distance, conditions may not be so rough.

However, if Lane tracks closer to the islands than Hector, then conditions would trend more severe. Likewise, if Lane is more spread out, conditions could get a little worse over the islands, when compared to Hector.

Additional threats from tropical storms and hurricanes are likely into the autumn, due to a developing El Niño.

Because El Niño is a plume of warmer-than-average waters over the tropical Pacific Ocean, the warm water just south of Hawaii can sustain more hurricanes than average over the eastern and central Pacific and cause them to be stronger in nature.

On average, there are approximately five tropical systems per year over the central Pacific basin.

There is a chance that Lane may cross the international date line later in August, but the chance of the system being a hurricane at that time is remote.

Hector survived to cross the date line on Aug. 13 but did so as a tropical storm and not a hurricane. When a hurricane crosses the date line into the western Pacific, it becomes a typhoon.