Last month’s rainstorms and rockslides are being quickly forgotten as the Big Island moves into a dry winter. ADVERTISING Last month’s rainstorms and rockslides are being quickly forgotten as the Big Island moves into a dry winter. Honolulu-based National Weather
Last month’s rainstorms and rockslides are being quickly forgotten as the Big Island moves into a dry winter.
Honolulu-based National Weather Service forecaster Tom Brichard said Tuesday that the dry period still is in its early phases, noting that just two weeks ago the Hilo area was seeing regular deluges.
“There were several days around the middle of (November) when there were 2-, 3-inch totals for the day,” he said.
In November, a total of 22.81 inches of rain fell on Hilo, which Brichard said is about 7 inches more than normal.
Baselines for normal are determined based on regular data from NWS rain gauges around the island.
November also was hotter than usual, with seven days breaking temperature records.
“Up through November, the water temperatures near the islands were warmer than normal, and that was one of the ingredients providing for the extra rainfall,” Brichard said.
The warmer waters were responsible for the summer’s increased rainfall, he said.
The coastal waters continue to hold extra heat, but as Hawaii moves deeper into winter, weather conditions are expected to stabilize as wind flow at the jet stream level in the upper atmosphere creates a large-scale sinking region. Sinking air means drier conditions.
And that’s what December has been so far: drier than normal.
As of Tuesday in Hilo, just 0.37 inches of rain were recorded this month, more than 2 inches below average.
Similar climate patterns are expected on the Kona side, which saw a wetter than normal summer that now is giving way to dry conditions.
The shift is exacerbated this year by a strong El Niño.
“With El Niño, we see a dry winter, and also a lot of high surf events,” Brichard said. “The two are correlated to some degree.”
The potential for high surf events, including those that could cause property damage, increases on the Kona side.
“In the short term, we have a swell … expected to build that would bring advisory level surf to the Big Island,” Brichard said. “People entering the water should be aware of the conditions.”
Email Ivy Ashe at iashe@hawaiitribune-herald.com.
