5 PM: Flooding Rains Possible Within Next 48 Hours

Monday, Aug. 6, 2018, 5 p.m.: Flooding Rains Possible Within Next 48 Hours

As of 5 p.m. Monday, the center of Hurricane Hector was approximately 735 miles ESE of Hilo at latitude 15.7 N and longitude 144.7 W, moving in a WNW direction at a speed of approximately 16 miles per hour. Strongest sustained winds are estimated at 155 miles per hour with higher gusts. Be aware that hurricanes are erratic and can change speed, direction and intensity quickly.

Due to the position, strength, and movement of Hurricane Hector, the following advisories have been issues by the Central Pacific Hurricane Center:

• The County of Hawai‘i is under a tropical storm watch. A tropical storm watch means damaging winds, damaging surf, and flooding rains are possible within the next 48 hours.

The following public safety measures and recommendations are now in effect:

• Secure large objects in your yard and prepare your house for strong winds.
• Secure all boats and aircraft.
• There are no evacuations at this time.

All roads are currently open. Whittington, Punalu‘u, and Milolii Beach Parks will be closed after tonight. All pavilion and camping permits for these three parks have been cancelled from Tuesday-Friday.

Animation, 6 a.m. to 1 p.m. HST. NOAA

Monday, Aug. 6, 2018, noon: Big Island Under Tropical Storm Watch as Hector Nears

Hawai‘i County Civil Defense Update

As of 11 a.m., the center of Hurricane Hector was approximately 850 miles ESE of Hilo at latitude 15.2 N and longitude 143.1 W, moving in a westerly direction at a speed of approximately 16 miles per hour.

Strongest sustained winds are estimated at 155 miles per hour with gusts near 167 miles per hour.

Hurricanes are erratic and can change speed, direction and intensity quickly.

Due to the position, strength, and movement of Hurricane Hector, the following advisories have been issues by the Central Pacific Hurricane Center:

The County of Hawai‘i is under a tropical storm watch. A tropical storm watch means damaging winds, damaging surf, and flooding rains are possible within the next 48 hours.

The following public safety measures and recommendations are now in effect:

• Secure large objects in your yard and prepare your house for strong winds.
• Secure all boats and aircraft.
• There are no evacuations at this time.
• All roads are currently open.
• Whittington, Punalu‘u, and Milolii Beach Parks will be closed after tonight.
• All pavilion and camping permits for Tuesday through Friday are cancelled.

3:56 AM HST, National Weather Service Update

A high pressure system northwest of the Hawaiian Islands will keep breezy trade winds in the forecast through Tuesday. Drier and more stable air moving across the region will keep shower coverage limited to mainly windward and mountain areas through Tuesday afternoon.

Hurricane Hector will cross into the local region from Tuesday night into Thursday and it remains too early to determine specific impacts on island weather at this time. Hector will likely clear the region by Friday, with typical summertime trade wind weather heading into next weekend.

A strong surface high center roughly 1,600 miles northwest of Kaua‘i will continue to maintain a ridge north of the state and produce breezy trade winds across the region for the next few days. Increasing downward motions, or subsidence, in the upper atmosphere has strengthened the trade wind inversion over the islands, decreasing shower activity into the isolated to scattered range.

Trade wind inversion heights are 6,000 feet at Hilo. This drier trade wind weather pattern will last through at least Tuesday afternoon. Satellite imagery this evening supports the drier weather forecast as a broad area of more stable stratocumulus is shown moving across the state.

Hector, Aug. 6, 2018, 6 a.m. HST. NOAA satellite image.

Hurricane Hector, Tuesday night into Thursday

Hurricane Hector has entered the Central Pacific basin with the current forecast track still keeping the center of Hector just south of the Big Island. However, hurricane impacts extend beyond the center of the low, and the average track errors of the hurricane this far out are up to 130 miles on either side of the forecast track.

Hector will move into the local region around Hawai‘i from Tuesday night into Thursday.

Weather impacts for each island remain highly dependent on the hurricane intensity and track with areas not affected by moisture from Hector remaining in a dry trade wind pattern.

Enhanced precipitation activity will develop over the eastern slopes of the Big Island from Wednesday morning into Thursday as deep tropical moisture associated with Hector and stronger trade winds will combine to produce numerous rain showers.

Hector, Aug. 6, 2018, 6 a.m. HST. NOAA satellite image.

Hurricane Hector, Friday through Sunday

Friday through Sunday, Hector will exit the region, and the area will likely return to a stable and mostly dry trade wind weather pattern. Scattered showers will tend to favor windward and mountain slopes through next weekend.

Hector-Kīlauea Effects

Volcanic emissions for the Kīlauea Volcano area will remain in a trade wind flow pattern through Wednesday morning with any ash and vog emissions drifting southwest into the Ka‘ū District of the Big Island. By Wednesday evening through Thursday, wind directions will likely shift towards the southeast as Hurricane Hector passes by to the south of the Big Island. These southeasterly winds will tend to push any emissions towards the northwest up through Hilo and along the northern slopes of the Big Island. Easterly trade winds will return by Thursday afternoon with any volcanic emissions drifting back towards the southwest.

The National Weather Service encourages everyone review their hurricane preparedness plans. A guide for hurricane preparedness can be found at www.ready.gov/hurricanes.

The State of Hawai‘i and each county also have preparedness information specific to the islands available from Civil Defense websites (Hawai‘i County).

Hector, Aug. 6, 2018, 6:30 a.m. HST. NOAA satellite image.

Marine Effects

A Small Craft Advisory (SCA) remains posted for the typically windier waters near the Big Island through Tuesday, due to strong high pressure far north-northwest of the state. Beyond Tuesday, additional areas will likely be included in the SCA for seas generated by Hurricane Hector.

A series of small south swells are expected through Wednesday. A small north swell is expected to arrive late Tuesday, peak Tuesday night and Wednesday, then lower gradually Thursday and Friday.

Hurricane Hector has generated swells that are expected to reach the eastern coastal waters today, and then gradually increase through Wednesday. This will result in gradually increasing surf along the east facing shores of the Big Island over the next few days, before the swell and resultant surf transition to the south during the second half of the week as Hector moves to the west.

Based on the latest guidance, large surf is expected over exposed shorelines on the Big Island and East Maui by the middle of the week. Shorelines of the smaller islands will be less impacted as they will be somewhat shadowed by the Big Island and Maui until Hector moves further west. We are also entering a period of high astronomical tides this week, so low lying coastal areas may have some coastal inundation issues. Stay tuned for the latest updates on Hector and its potential impacts on winds, seas, and surf across the area.

Hector, Aug. 6, 2018, 6:30 a.m. HST. NOAA satellite image.

Fire Effects

Wind speeds will remain breezy through Tuesday, especially down wind of terrain, with gusts from 20 to 30 mph over mountain ranges and through leeward valley areas. A drier and more stable air mass will continue to limit shower activity across the state with scattered showers lingering over windward and mountain sections. Although critical fire weather thresholds will likely not be crossed during the next couple of days, many of the ingredients will remain in place for elevated fire activity. Hurricane Hector will be crossing the region from Tuesday night through Thursday and it remains still too early to determine specific impacts for local island weather. That said, those areas not directly impacted by Hector could see continued dry conditions with an increase in trade wind speeds.

Small Craft Advisory until 6 p.m. Tuesday for Big Island leeward and southeast waters, Ma‘alaea Bay, Pailolo Channel and Alenuihaha Channel.

Closely monitor this major hurricane as it moves closer to the state.

Hector, Aug. 6, 2018, 6:30 a.m. HST. NOAA satellite image.