Hawaii on Alert for Heavy Rain, Wind From Hilda

By Brett Rathbun, AccuWeather.com Meteorologist

August 12,2015; 9:15PM,EDT

 

 

Hilda, currently a tropical storm, will approach the Big Island of Hawaii with heavy rain, locally gusty wind and dangerous surf over the next few days.
A surge of tropical moisture will push across the islands of Hawaii.
"Even if Hilda does not make a direct landfall, upslope flow still threatens to bring a significant amount of rainfall to the Big Island of Hawaii," AccuWeather Meteorologist Evan Duffey said.
Satellite image of Hilda. (Image/NOAA) "Some areas of the Big Island, including the city of Hilo, could see flooding conditions," he said.
Wind gusts over 40 mph are possible from Hilda, especially along the southeast coast of the Big Island.

The heaviest rain bands may lead to localized flash flooding, especially across areas that have seen large amounts of rain so far this month. Any downpours could also lead to reduced visibility and the risk of hydroplaning for motorists traveling at highway speeds.
"Heavy rain will hit the Big Island beginning on Wednesday night; this will result in flash flooding and mudslides, especially along the southern mountains and eastern-facing slopes," Duffey said.

Locally gusty winds in bands of rain or squalls can cause sporadic power outages.
In addition to the heavy rain and wind, dangerous surf and rip currents will occur.
Small craft operators should consider remaining in port late this week, as seas will build. Bathers, boarders and boaters should heed all advisories as they are issued.

Scary Flames Overtake Hawaii Highway

Hilda is expected to track south of the Big Island, similar to the track of Iselle during early August of last year.
"Hilda is likely to track much farther south than Guillermo and could take a track more similar to Iselle in 2014," AccuWeather Senior Meteorologist Alex Sosnowski said.

"Because of this track grazing or just missing the islands to the south, there is the potential for impacts similar to Iselle," Sosnowski said. "The proximity of the storm track to the islands and how much Hilda weakens will all come to bear on the amount of rain and wind that occurs."
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Iselle brought more than a foot of rain to parts of the Big Island.
"Since Hilda is likely to be a weaker system and could travel farther south than Iselle, conditions are likely to be less intense from Hilda, but perhaps more significant than Guillermo," Sosnowski said.
How El Niño Affects Tropical Activity Across the Atlantic and Pacific
An El Niño pattern is defined by above-normal sea-surface temperatures in the equatorial Pacific Ocean. Because tropical systems develop and strengthen due to warm ocean temperatures, this typically leads to a busy hurricane season across the eastern and central Pacific Ocean.
"As El Niño strengthens in the central and eastern Pacific, warm sea-surface temperatures provide a favorable environment for tropical systems to develop," AccuWeather Meteorologist Edward Vallee said.
While the hurricane season is busy across the Pacific during an El Niño season, the Atlantic typically has below-average activity.
"In the Atlantic, a strengthening El Niño leads to increased wind shear, which highly inhibits hurricane development. This has led to significantly decreased tropical activity over the Atlantic for much of this season," Vallee said.

Despite being in the middle of the summer season, the peak period for tropical development across the Atlantic is not until the early to middle of September.