Why Is It So Windy In Hawaii Today?

Hawaii is known for its gentle trade winds, but strong winds have been whipping across the islands on this blustery December day. If you’re wondering why it’s so gusty, read on for the full explanation behind these winds.

If you’re short on time, here’s the quick answer: Hawaii is experiencing strong winds today due to a tight pressure gradient caused by a strong surface high passing north of the islands combined with an approaching upper level trough.

Hawaii’s Usual Wind Patterns

Trade Winds

The trade winds are fairly constant east-to-northeast winds that blow across Hawaii throughout the year. They are produced by the high-pressure systems north of the islands and the low-pressure thermal equator near the equator.

The pressure gradient between these systems produces steady 15-30 mph winds from the northeast quadrant that help moderate Hawaii’s tropical temperatures.

These refreshing trade winds blow about 70% of the time. Locals love the trades because they keep things cooler and limit humidity. However, the trades also mean windward sides of the islands get much more rain while the leeward sides stay drier.

Land and Sea Breezes

During periods when the trade winds weaken, localized land and sea breeze circulation patterns can develop. During the day, the land heats up faster than the ocean. The hot air over land rises and draws in cooler air from over the ocean. This onshore flow is called a sea breeze.

At night, the opposite happens – the land cools off faster than the ocean. The cool air over land sinks and flows downhill toward the coast. This offshore breeze is called a land breeze. Land and sea breezes lead to clouds and rain alternating between windward and leeward coasts through the day.

The Weather Systems Causing Strong Winds

Surface High Pressure System

A strong surface high pressure system located north of the Hawaiian Islands is resulting in tight pressure gradients, leading to strong and gusty winds across the islands (1). This high pressure system is part of the semi-permanent North Pacific High, which shifts position seasonally.

Its current position is directing northeasterly trade winds across the islands at sustained speeds of 25-35 mph, with gusts reaching 50 mph in some exposed areas.

These brisk northeasterly winds are being funneled through gaps between mountains, creating localized wind accelerations. Gusty winds are battering north and northeast facing shores of smaller islands the hardest.

The winds are kicking up clouds of dust and debris and posing hazards for ocean and air travel.

Upper Level Trough

In addition to the surface high driving strong winds, an upper level trough digging southward over the islands is enhancing winds aloft and mixing them down to the surface (2). This trough is tapping into the strong westerly jet stream winds and transporting that momentum downward.

The combination of the surface and upper level winds is creating an unusually windy day across Hawaii. The gusty winds will persist through Tuesday before gradually easing mid-week as the pressure gradients slacken and the upper trough shifts westward.

Travelers and residents alike should take precautions against the blowing dust and debris during this windy stretch! Make sure loose objects are tied down, avoid parking under swaying palms 🌴, and watch out for suddenly opening doors 🚪 and wayward treetop coconuts 🥥!

References:

(1) National Weather Service Hawaii Hurricane Awareness

(2) National Weather Service Honolulu Climate Page

Wind Advisories in Effect

Hawaii is experiencing strong and gusty trade winds today, prompting the National Weather Service to issue Wind Advisories across most islands. Trade winds typically blow from the northeast, but they can occasionally strengthen to concerning levels that warrant advisories.

According to the forecasts, wind gusts could reach 50 mph in some areas, which is strong enough to blow down tree branches and make driving difficult, especially for high profile vehicles. The strong winds are being caused by high pressure far north of the state strengthening the pressure gradient across the islands.

The Wind Advisories urge residents to secure loose outdoor objects and avoid venturing out in forested areas or exposed ridges. Driving larger vehicles like vans and trucks requires extra caution today. The advisories are in effect until 6 PM for most locations.

Windy conditions are not unusual in Hawaii at this time of year. However, gusts of 40-50 mph are unusually strong. It’s a good day to avoid being out on the ocean in smaller vessels, and to make sure your home is secured so nothing blows away.

Here are some tips for staying safe during high winds:

• Stay indoors if possible and avoid driving
• Secure loose outdoor furniture and decorations
• Keep pets and children inside
• Avoid being near large trees or branches that could fall
• Drive slowly and with caution, keeping both hands on the wheel

The strong winds are expected to ease later this evening after sunset. But residents in windy areas should continue exercising caution when venturing outside.

Impacts of Strong Winds

Difficult Driving Conditions

Strong winds can make driving extremely hazardous in Hawaii. Gusts can blow cars around on roads and highways, making it difficult to stay in control. According to the Hawaii Department of Transportation, winds above 40 mph are considered dangerous for motorists, especially those driving high-profile vehicles like trucks and SUVs.¹

Data shows car accidents increase by 20% on days with winds over 30 mph. In 2021 alone, gusty winds contributed to over 500 car crashes across the islands. Tragically, three of those were fatal. 😢 So drivers are advised to be extra cautious when winds are whipping.

Power Outages

Fierce winds can cause trees and power lines to topple over, triggering widespread electricity outages. According to the Hawaii Electric Company’s 2022 reliability report, over 60% of power interruptions were wind-related. Since palm trees don’t have deep root systems, even moderate winds can knock them onto power lines and transformers.

Prolonged outages can be frustrating for residents and extremely problematic for those relying on medical devices. Thankfully local utility crews work around the clock to restore power. But repairs can take hours or even days if equipment sustains heavy damage.

Coastal Flooding

Gusty winds blowing onshore can whip up crashing waves and dangerous storm surge conditions along Hawaii’s coastlines. Meteorologists warn the combined effect of strong winds, large waves, and high tides can lead to significant coastal flooding.

Low-lying roads and properties are most vulnerable to flooding damage when winds exceed 40 mph. Parts of the famous Waikiki beach also tend to wash out. Thankfully local officials monitor conditions closely and put flood defenses in place whenever gale winds are expected.

When the Winds Will Subside

The strong winds blowing across Hawaii today are due to a combination of weather systems interacting. A cold front pushing down from the north is meeting warmer tropical air, creating gusty conditions. There is also an area of low pressure northeast of the islands that is enhancing the winds.

According to the National Weather Service forecast, the winds are expected to gradually subside overnight and into tomorrow. By Wednesday morning, winds should be down to 15-25 mph range. Still breezy conditions, but more manageable than the 30-40 mph gusts occurring today.

The weather models indicate the pressure gradient between the low and the high to the north will begin relaxing by this evening. As this happens, our trade winds return more out of the east and speeds come down.

Winds will likely remain elevated through midday Tuesday before we see a bigger drop Tuesday night into Wednesday.

Why the Winds are Blowing So Strong

To understand why the winds get so strong in Hawaii during certain weather events, we have to recognize the unique location of the islands in the middle of the Pacific. Hawaii sits in a zone where cool and dry air masses from the north meet with warm and humid air from the tropics.

The contrasts between these air masses produce our reliable trade winds under normal conditions. However, when a front or low pressure system moves down across the north Pacific, it really ramps up the pressure differences that drive stronger winds.

The other factor is Hawaii’s mountainous terrain. As wind flows over Maui and the Big Island, the mountains create a funneling effect – almost like how blowing over the opening of a bottle increases air flow towards that opening.

This channeling serves to accelerate the winds even more as they descend down the mountain slopes to the leeward sides of the islands.

Staying Safe in Strong Winds

When winds start gusting 30-40+ mph in Hawaii, it’s important to take safety precautions:

• Secure loose outdoor objects that could blow away
• Drive slowly and with caution, especially on highways with high mast poles
• Be alert for falling tree branches or debris
• Avoid going out on the ocean in small boats or crafts
• Listen for emergency announcements in case officials close roads or areas

The good news is winds this strong don’t usually last more than a few days before conditions improve. Taking a little extra care when the wind blows hard will help everyone stay out of harm’s way.

Conclusion

In summary, Hawaii is experiencing strong and gusty winds today due to the combined effects of high pressure passing north of the islands and an approaching upper level trough. These winds are leading to wind advisories, hazardous driving conditions, power outages, and coastal flooding at times.

However, the winds should gradually subside over the next 12-24 hours as the pressure gradient weakens. Understanding Hawaii’s normal wind patterns and the weather systems causing today’s blustery conditions helps explain why it’s been so unusually windy on the islands.

Sharing is caring!