Hurricane Lane a Slow-Moving, Potential Flood Disaster; Over 30 Inches of Rain Possible in Parts of Hawaii Through Saturday

Weather Channel

Hurricane Lane is already unleashing torrential rain in parts of Hawaii, and may produce disastrous rainfall flooding and landslides over much of the island chain, in addition to battering surf, coastal flooding and high winds through Saturday.

This threat was summed up succinctly by The Weather Channel hurricane expert, Dr. Rick Knabb, in a tweet Thursday morning.

A hurricane warning remains in effect for Hawaii’s Big Island, Maui and Oahu, including Honolulu, meaning that hurricane conditions are expected within the warning area.

A hurricane watch remains in effect for Kauai County. This means hurricane conditions are possible within the watch area, and a watch is typically issued 48 hours before the onset of tropical-storm-force winds that may make preparations difficult or dangerous, according to Central Pacific Hurricane Center.

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Latest Hurricane, Tropical Storm Alerts

(A watch is issued when tropical storm or hurricane conditions are possible within 48 hours. A warning is issued when those conditions are expected within 36 hours.)

Happening Now

The center of Lane is about 210 miles south-southwest of the Big Island’s Kona Coast or about 305 miles south of Honolulu, moving northwestward. Lane has weakened somewhat, but remains a powerful Category 4 hurricane.

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Current Storm Status

(The highest cloud tops, corresponding to the most vigorous convection, are shown in the brightest red and pink colors. Clustering, deep convection around the center is a sign of a healthy tropical cyclone.)

Lane’s outer rainbands are already drenching parts of the Big Island. Rainfall rates upwards of 1 to 3 inches per hour have been occurring in these bands.

Up to 15.66 inches of rain had been reported on the Big Island at Waiakea Experiment Station over the past 24 hours. Hilo had seen over 12 inches or rain in that same 24-hour period ending early Thursday morning.

The heavy rain has caused road flooding on the Big Island, including the city of Hilo, and landslides have occurred blocking some roads.

(LATEST NEWS: Hawaii Prepares for Lane)

Rainbands from Hurricane Lane will continue to gradually overspread the rest of the Hawaiian Islands Thursday.

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Current Radar, Watches and Warnings

(Watches and warnings are issued by the National Weather Service.)

Forecast Track Uncertainty

Even as Lane moves toward Hawaii, its forecast track and intensity the next couple of days still remains uncertain at this rather critical time, and small changes to its track and intensity are important for some potential impacts in the Hawaiian Islands.

Perhaps the most dangerous impact from Lane won’t depend as much on its intensity or exact track, but rather may result from its slowing forward speed in the form of heavy rainfall, as we’ll detail in our impacts section below.

Lane is now moving north-northwest after reaching the edge of subtropical high pressure, which had previously been steering it.

The most critical turn for Lane is an expected left-hand turn toward the west sometime Friday or Saturday.

The key is how soon and sharp that left-hand turn is, which will determine how close the core of Lane’s strongest winds come to the islands.

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Projected Path and Wind Field

(The red-shaded area denotes the potential path of the center of the tropical cyclone. It’s important to note that impacts (particularly heavy rain, high surf, coastal flooding, winds) with any tropical cyclone usually spread beyond its forecast path.)

If Lane moves along the southern or western portion (left side) of its forecast projected path, it would be far enough from the islands to avoid the worst wind impacts of its core but still produce flooding rainfall, strong winds, dangerous surf and rip currents.

If, however, Lane moves along the northern or eastern side (right side) of its forecast projected path, essentially making its left-hand turn later or less sharp, damaging winds from the hurricane’s core could swipe parts of the islands, in addition to torrential rain from the core and more damaging coastal flooding from both the setup of battering waves and water rise for those areas prone to water rise.

(MAPS: Interactive Hurricane Tracker)

While waters are sufficiently warm, wind shear is increasing, and this will gradually, then more rapidly weaken Lane. Once Lane weakens sufficiently, it will make that left-hand turn, steered by lower-level winds.

So, as happens qutie often, the intensity and track forecasts depend on each other.

A sooner weakening of Lane means a sooner left turn farther from the islands. A later weakening means the core of Lane would track closer to the islands before it makes a later left-hand turn.

Adding to the complexity is the potential for Lane’s circulation to be disrupted by the higher terrain of the islands.

Despite all that, Lane could still be a hurricane near or off the coast of Maui County or Oahu Friday, areas that are not accustomed to tropical storm or hurricane conditions.

Residents in Hawaii, particularly in watch and warning areas, should rush storm preparations to completion, including putting together an emergency kit and a family emergency plan. Those with vacation plans to Hawaii through Saturday should consider changing their plans.

Hawaii Forecast Impacts

Here is a break down of potential impacts from Lane.

Rainfall Flood Threat

  • Regardless of the exact track, bands of heavy rain will hammer the Hawaiian Islands through Saturday.
  • These heavy rainbands may occur both well ahead and for some time after the closest approach of the center of Lane.
  • Moist winds up the slopes of the hills and mountains on Lane’s northern and eastern flanks could lead to prolific rainfall, potentially unleashing deadly, destructive flash flooding and landslides.
  • According to the Central Pacific Hurricane Center, isolated maximum rainfall totals of more than 30 inches are possible, particularly over south- and/or eastward-facing slopes.
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Lane Rainfall Outlook

(This should be interpreted as a broad outlook of where the heaviest rain may fall and may shift based on the forecast path of the tropical cyclone. Higher amounts may occur where bands of rain stall over a few hours or in mountainous locations.)

High Wind Threat

  • At least tropical-storm-force winds (39 to 73 mph) are expected in most areas of the islands.
  • These tropical-storm-force winds are most likely to begin later Thursday in Maui County, late Thursday night in Oahu and late Friday in Kauai County.
  • There is a small chance of hurricane-force winds (74 mph or higher) in parts of the islands, particularly along the western or southern coasts.
  • Small changes in the track and intensity forecast will make the difference between the core of Lane’s strongest winds affecting at least parts of the islands or remaining offshore.
  • Regardless, the combination of heavy rain and strong winds could down more trees than strong winds alone.
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Power Outage Potential

High Surf/Coastal Flood/Storm Surge Threats

  • Large swells generated by Lane will spread across the Hawaiian Islands Thursday.
  • Dangerous surf conditions and rip currents are expected, especially on exposed west-, south-facing coasts, including those typically not accustomed to large waves, such as Waikiki Beach, Maui and the Kona Coast.
  • The surf could be damaging in spots.
  • Coastal flooding – possibly more locally significant storm-surge flooding if the core of Lane moves close enough – is also expected but depends on the exact track of Lane.
  • Water levels may rise by as much as 2 to 4 feet above normal tide levels along south- and westward-facing coasts near where the center of Lane passes, according to the Central Pacific Hurricane Center.

Tornadoes

  • As always with hurricanes and tropical storms affecting land, a threat of waterspouts and tornadoes is in play, particularly in discrete cells embedded in outer rainbands.
  • Given these are embedded in Lane’s rainbands, they may develop quickly and move rapidly.
  • You may not be able to see a tornado before it arrives.
  • Take shelter immediately if the National Weather Service issues a tornado warning for your area.

Hawaii Hurricane History

Lane is the strongest hurricane to track within 300 miles of Hawaii, according to NOAA’s historical database. While 1994’s Hurricane John had stronger maximum sustained winds, Lane’s lowest pressure was lower than John’s, and John only came within 319 miles from South Point on the Big Island.

According to NOAA’s best track database, there is no record of a hurricane track within 65 nautical miles of either Maui or Honolulu since statehood.

There have been three notable hurricanes that struck the western island of Kauai during that time: landfalls of Iniki in 1992 and Dot in 1959 and an eyewall brush with Iwa in 1982.

(MORE: How Unusual are Hawaii Hurricanes)

Three of the previous Category 5 central Pacific hurricanes occurred in 1994 during a hurricane season that featured a central Pacific flavor of El Niño called Modoki El Niño. Modoki El Niños occur when the warmest pool of water compared to average occurs in the central Pacific rather than in the eastern Pacific.

Warmer water allows tropical cyclones to readily intensify. A Modoki El Niño opens the window for strong hurricanes in the central Pacific as long as atmospheric conditions such as wind shear and humidity are also favorable.

Check back with us at weather.com for the latest on Lane and its potential impacts in Hawaii.

Recap of Lane So Far

Lane formed as a tropical storm in the eastern Pacific on Aug. 15 and became a hurricane the next day.

Tuesday evening, Hurricane Lane joined an exclusive company of central Pacific Category 5 hurricanes, the first since Ioke in 2006, only the second on record within 350 miles of Hawaii(John in 1994 was the other) and the most intense North Pacific hurricane east of the International Date Line since Patricia in 2015.

https://weather.com/storms/hurricane/news/2018-08-22-hurricane-lane-hawaii-forecast

11 thoughts on “Hurricane Lane a Slow-Moving, Potential Flood Disaster; Over 30 Inches of Rain Possible in Parts of Hawaii Through Saturday

    1. Spoke with the lady at the storage place about this yesterday… she’s from Hawaii – has lots of relatives there.

      Stay safe, galen.

  1. Let’s pray for our good brother’s and sisters in Hawaii.

    Volcanoes. ..

    Hurricanes. ..

    I mean fk….

    What’s next…

    Illegal aliens crossing the border on a fkng boat to the big isle..?

  2. Yeah, we’ve had 3 road mudslides on our side already by this morning, problem is this Hurricane has stalled somewhat, it is doing what it wants, they’re talking about it potentially turning and going direct into Maui/Big Island…. Our volcano mountains protect us somewhat but this is a massive Hurricane, slowly starting to weaken…

    We’ll see what happens over the next few hours…

    Aloha, Norm

      1. Yes, Hilo Side, Not sure where Galen stay… But Our side getting pounded by rains, West side where Hurricane is, still yet calm. Thanks for the well wishes guys…

        1. I stay east side, too. Calmer now, but may be the eye. We’ll see.

          Thanks guys for your concern and your prayers. Prayers are like little ambassadors that go out into the ethers summoning good. I do believe in them.

          🙂

          .

          1. If only our prayers could have stopped the manufactured onslaught before they started it.
            Your safety and comfort is what we are praying for now.

  3. Update 4 p.m.:

    Oh boy, this is some hurricane, and the damn thing is hovering and they tell us it will take days to pass. The whole island is a mess. So far the interior of our home is okay since we are all boarded up, but that makes it kinda dark all day. The yard and patio are a sloshy bog. Downtown and the surrounding parks are flooded and power has been on and off. Land slides, very high surf, swollen rivers. Many roads closed as well as restaurants, businesses, tourist attractions, etc. Lots of floating debris and trees down. The main landslides are on the saddle road, the main route for crossing the island. Right now, no heavy winds, but continuous, extremely strong downpours. Some are evacuating to higher ground. One thinks of the homeless at such times, and one hopes for a more just world.

    .

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