Unsettled weather will likely continue

It’s wet. It’s wild. It’s our crazy weather.

Thanks to an unusual convergence of atmospheric features, cold air is blasting Hawaii from the north while moisture is coming at us from the south, making conditions in the islands rather windy, wet, chilly and unstable.

And it looks like it’s going to be with us through the weekend — and maybe even into the middle of next week, according to weather forecasters.

Glenn James, senior weather specialist with the Pacific Disaster Center on Maui, said Hawaii’s unstable weather over the last week can be explained by an unusual set of atmospheric features that conspired to make conditions cold and somewhat unpredictable.

A large pressure pattern in the Central Pacific has featured a counterclockwise rotating low-pressure system north of Hawaii, he said, while a clockwise rotation area of high pressure is spinning to the east.

“These two weather features are channeling cold air from northern latitudes down towards the tropics — and across the islands,” said James, who also runs the Hawaii Weather Today website.

At the same time, he said, several low-pressure systems have been moving over the state, making the atmosphere unstable and especially shower-prone while the frigid air aloft is turning the moisture into snow at the summits of Maui and the Big Island.

More snow showers dusted Hawaii’s tallest mountains Thursday.

A winter storm warning was expected to remain in effect for Haleakala and the Big Isle summits through this afternoon, said National Weather Service forecasters, who also warned of icy and dangerous summit roads with low visibility as snow shower bands pass over the mountains.

Last weekend’s storm brought high winds that battered the islands, bringing down trees, causing power outages and damaging structures. At the Mauna Kea summit, winds that reached a whopping 191 miles an hour caused minor damage to a couple of observatories, and the U.S. Department of Agriculture were asking farms and ranches to report damage.

Although breezy trade­winds were expected to continue today, the forecast called for the bluster to back off somewhat this weekend.

But the unsettled weather is likely to persist, forecasters said, maybe even through midweek as the Kona low lingers, bringing additional moisture from the south.

Meanwhile the National Oceanic and Atmospheric Administration announced Thursday that the long-anticipated El Nino weather pattern has finally arrived and is likely to continue through the spring.

In Hawaii the El Nino phenomenon primarily means drought in the winter, and that’s precisely what happened during last year’s El Nino event.

This time, however, the El Nino pattern is considered weak and likely will have little influence on Hawaii’s weather, said state climatologist Pao-Shin Chu.

“When you have a strong El Nino, you know what is expected. The signal is clear. But not this time,” Chu said.

Despite the recent rainfall, drought continued to worsen in Hawaii — although at a slower pace.

According to the Hawaii Drought Monitor, an area of severe drought more than doubled in size in South Kohala over the last week. Otherwise, drought conditions in the islands largely remained the same as last week, with nearly 85 percent of the state experiencing at least abnormally dry conditions.

Oahu appeared to be the island least affected by drought as only the Leeward side, from Ewa to the Waianae Coast, showed either dry or drought conditions.

Such conditions could ease a bit this week as the chance of rain is in the forecast through the weekend and maybe longer.

Chu, a University of Hawaii meteorology professor, said the weak El Nino likely means that drought will be less of a concern this spring.