A powerful system called a Kona storm will bring flooding rainfall, strong winds, some severe thunderstorms, even mountain summit blizzard conditions to Hawaii into this weekend.
Flood watches and high wind warnings are in effect throughout parts of Hawaii.
A potent low pressure system is pulling deep tropical moisture northeastward across the island chain. While conditions are slowly beginning to lessen for some of the islands, flood watches remain for The Big Island, Maui, Molokai, Lanai, and Kahoolawe.
Higher elevations of Maui County has seen rainfall totals approaching 40 inches. The remainder of the islands have seen rainfall between 10 and 20 inches so far.
Several trees were downed by strong wind gusts Friday on the southern side of Oahu and gusts exceeded 60 mph on several islands. A wind gust of 81 mph was reported on Makapuu Beach. The Kahului Airport in Maui reported a wind gust of 67 mph on Saturday. However, stronger gusts are occurring across the higher elevations. Kaiaulu Puu Waawaa (nearly 4,000 ft in elevation) reported a wind gust of 135 mph on Saturday and Kula (9,700 ft in elevation) reported a wind gust of 108 mph on Friday evening.
Power was knocked out to around 125,000 customers throughout the state by early Saturday morning. By Sunday morning, that number dropped to just under 50,000.
Forecast Timing And Threats
Unfortunately, this Kona low will remain relatively parked in place into the weekend, continuing to pump moisture into the state.
While conditions will improve from west to east during the weekend, the eastern part of the state will continue to see heavy rain and gusty winds this weekend.
Flash flooding is the greatest threat from this storm, with the Big Island and Maui picking up at least four inches of additional rain everywhere except the immediate north coast of the Big Island. The heaviest rainfall totals should occur on the south- or southwest-facing coasts and mountain slopes.
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A few severe thunderstorms are possible with damaging winds and large hail. Unusually conducive conditions for Hawaii standards are expected to come together for severe weather.
Gusty and potentially damaging winds are possible during this period of peak impact. Winds in the lower elevations could contiue to exceed 50 mph, but the Big Island volcanic summits could see more gusts over 100 mph. These gusty winds below the tree line could cause tree limbs to break and block roadways and cause additional power outages.
The summits on the Big Island could also see significant winter impacts, after more than a foot of snow was forecast. Strong wings will create blowing snow and dangerous conditions.
Hurricane force winds are possible over the coastal waters creating hazardous offshore conditions.
(MORE: For even more granular weather data tracking in your area, view your 15-minute details forecast in ourPremium Pro experience.)
What Is A Kona Low?
Kona lows are storm systems that set up to the west or northwest of the islands and draw up lots of moisture from the south, creating messy and sometimes dangerous conditions. They can bring widespread heavy rain to the islands with the threat of flash flooding, as well as damaging, gusty winds.
This is a phenomenon that occurs most often in January, although it can happen anytime between October and May.
This is a reversal from typical Hawaii weather.
The trade winds across Hawaii typically blow from the northeast. That means windward areas, generally the northeast sides of the islands, typically see more showers. On the Big Island, Hilo is the best example of this. They average a whopping 120.39 inches of rain a year.
But when a Kona storm moves in, it will bring winds from the southwest or "kona" side (or southwest side) of the islands. It's these storms that soak normally drier locations in the islands, including Honolulu and the Kona coast of the Big Island. Honolulu averages only 16.41 inches of rain a year.
