Hawaiʻi Wet Season Rainfall Outlook favors above average rainfall
October 19, 2022, 1:26 PM HST
* Updated October 20, 12:14 AM
The National Weather Service in Honolulu has issued its projections for the upcoming wet season, saying above average rainfall, especially from December to April, could help to relieve drought.
But the agency notes that rainfall distribution can be influenced by the strength of La Niña, making the exact location of rain subject to strong or weak conditions.
Kevin Kodama Senior Service Hydrologist with the Honolulu Weather Forecast Office said the current climate models favor higher than average precipitation for the Hawaiian Islands.
“Stronger La Niña events can have a higher than normal trade wind frequency which will focus rainfall on windward areas,” according to the Wet Season Outlook. “Weaker La Niña events tend to have more weather systems that produce significant leeward rainfall,” according to the report, which notes that a weak to moderate event is favored.
According to NOAA’s Climate Prediction Center, La Niña has persisted through 2022 so far, and is expected to continue into spring 2023.
Kodama said this will potentially be the third year in a row of La Niña conditions during the wet season. “This has only happened twice before since 1950, so it’s a pretty unusual situation,” he said during a morning press briefing.
Kodama said the wet season and Central Pacific Hurricane Season are closely tied to what the La Niña and El Niño-Southern Oscillation cycles are doing. Because we are in La Niña, that favors a less active tropical cyclone season here in the islands, according to agency officials.
According to Kodama, areas that are in significant drought right now like Maui County and Hawaiʻi Island have a chance that drought may persist through the upcoming wet season, especially over the leeward areas. “There’s a better likelihood of drought recovery in the west half of the state with Kauaʻi and Oʻahu seeing a better chance of having a full recovery from drought,” he said.
In early August, drought conditions on Maui worsened from extreme to exceptional (D3 to D4 category). There were brush fires and drought conditions contributed to severe crop and pasture losses from axis deer, according to a recap of the dry seasons provided by agency officials.
“Whether or not we are projecting an above or below average wet season, you can have flooding even in drought. In Hawaiʻi these events can happen so quickly. You can go from bright sunny skies to thunderstorms within an hour,” said Kodama, who encouraged the public to always be on the lookout and informed of forecasts.
The agency offered the following wet season preparedness reminders:
- Do not drive on roads with fast-flowing water.
- Just 1 to 2 feet of fast-flowing water can sweep most vehicles off a road.
- Roads may also be severely undercut.
- Do not walk across flooded streams.
- If you’re hiking and get stranded, wait for the water to recede.
- Streams in Hawaiʻi generally recede quickly.
- Expect more rainy weather impacts.
- Increased road travel times
- Possible detours or road closures due to flooding or landslides.
- Outdoor activities may be postponed, canceled, or adjusted.
- The wet season brings increased potential for lightning strikes.
- Be prepared for power outages, especially when thunderstorms are forecast.
- Move indoors when you hear thunder or see a flash of lightning.
- Lightning strikes can occur even in areas where it is not raining.
- Although rare, thunderstorms occasionally produce damaging winds, large hail, and tornadoes in Hawaiʻi.
- If you travel through a flood-prone area, identify alternate routes ahead of time.
- If you live in a flood-prone area, have an evacuation plan in case flood waters quickly threaten your home.
- Stay informed of conditions that could change rapidly
- Sunny skies can turn cloudy with intense rainfall in less than an hour.
- Check out the latest forecasts, watches, warnings, and advisories via the media, NOAA Weather Radio, the Internet, or one of several weather mobile phone apps.
- Wireless Emergency Alerts (WEA) on mobile phones notify you that you’re in a significant, life-threatening flash flood warning area.
Helpful weather resources include the following: