Hurricane Douglas could hit Hawaii over the weekend

The storm strengthened into a Category 1 storm Wednesday morning. It has sustained winds of 80 mph and is traveling westward toward Hawaii at a rate of 16 mph, according to the hurricane center.

The hurricane center said additional strengthening is expected over the next day or two and Douglas may develop into a Category 3 or higher storm. A Category 3 storm has sustained winds from 111 to 129 mph.

Douglas has hurricane-force winds extending outward up to 10 miles (20 km) from the center, and tropical storm-force winds extending outward up to 105 miles (165 km). The storm was about 1,690 miles (2,715 km) east of Hilo, Hawaii, as of 11 a.m. Wednesday, the hurricane center said.

"Douglas is expected to move near or over portions of the Hawaiian Islands this weekend, and there is an increasing chance that strong winds and heavy rainfall could affect portions of the state beginning on Sunday," the hurricane center said.

While Douglas is currently projected to reach Hawaii, environmental conditions mean that the storm could weaken significantly before it does.

Rare for strong hurricanes to reach Hawaii

"It is fairly common for hurricanes to track towards Hawaii, but they usually dissipate or at least weaken considerably before impacting the islands," said Phil Klotzbach, a research scientist at Colorado State University. "For example, both Lane and Olivia impacted Hawaii in 2018. Also, in 2016, both Lester and Madeline threatened Hawaii."

Although a hurricane's effects on Hawaii can be severe, it is rare for major hurricanes to reach the shores of the island chain. For one, the Hawaiian Islands are a small plot of land amongst the largest ocean basin in the world making the statistical probability of a direct landfall very low.

Hawaii covers 6,423 square miles of land divided up among six main islands, making the chance of a direct landfall even less likely. Florida, by comparison, is a significantly easier target for hurricanes to strike as it covers more than 50,000 square miles

Douglas is expected to bring wind, rain and dangerous surf to Hawaii by the weekend, although it may be downgraded to a tropical storm by the time it reaches the islands.

There are other key weather features, like wind shear and dry air, that meteorologists look for to either steer storms away from Hawaii or weaken them dramatically before they reach the white sandy beaches of Honolulu.

One of the more influential atmospheric processes is a semi-permanent north Pacific high pressure system which often forces a detour of oncoming tropical systems. However, when that high pressure is weaker than normal or is broken down by an incoming trough, trouble can brew.

Slow start to the East Pacific hurricane season

In a season that has seen early storm formation in the Atlantic, the eastern Pacific has been slower for storm development than in previous years.

"Douglas has been upgraded to a 65-kt hurricane, the first of the 2020 eastern Pacific season," according to the hurricane center. "During the period of reliable records, this is the 4th latest date in which the first hurricane of the season has formed."

A slow Pacific hurricane season, especially when paired with an active Atlantic hurricane season, is a sign of a La Niña event, which forecasters have predicted could occur this year.

Under La Niña, global convection wind currents yield sinking air over the eastern Pacific, and rising air over the western Atlantic. Sinking air patterns increase wind shear, a sudden shift in wind direction, speed or both, which can rip apart hurricanes before they have a chance to grow. ​​​