11 A.M. UPDATE: Ana Upgraded to a Hurricane

Ana was upgraded to a hurricane shortly before 11 a.m. today.

A tropical storm watch has also been issued for Maui County, Oʻahu, and Kauaʻi counties, including adjacent coastal waters.

Summary of Alerts

TROPICAL STORM WATCH – Now issued statewide, including all coastal waters.

HURRICANE WARNING – Posted for all Hawaiian Offshore waters, starting this afternoon.

TROPICAL STORM WARNING – In effect for all Hawaiian Offshore waters, Big Island leeward coastal waters, and Big Island southeast waters

FLASH FLOOD WATCH – Already posted for theBig Island. It is anticipated that it will be posted for the entire state beginning this afternoon

Current situation

Hurricane Ana is carrying maximum sustained winds at 75 mph, gusting to 93 mph. The storm is moving to the west-northwest at 14 mph.

Hurricane force winds extend 25 miles from the center. Tropical storm force winds extend 90 miles from the center of the system.

At 11 a.m. HST, on Friday, Oct. 17, the center of Tropical Storm Ana was last located near 16.4 N and 155.2 W, about 230 miles south of Hilo; 320 miles southeast of Kahului, Maui; 350 miles southeast of Kaunakakai, Molokaʻi; 325 miles southeast of Lānaʻi City; and 380 miles south-southeast of Honolulu, Oʻahu.

A slight turn to the northwest is expected today and Saturday. A decrease in forward speed is expected Saturday night and Sunday. On this forecast track, the center of Ana will pass about 115 miles southwest of the Big Island tonight and about 115 miles southwest of the rest of the main Hawaiian islands this weekend. Some strengthening is expected today. The system is expected to weaken a little slower than indicated in the last update, starting late Saturday.

Ana is expected to get nudged slightly northwest later today. A new ridge is expected to

Satellite imagery, 11am 10-17-14. Image: NWS / NOAA

form north of our islands just as Ana would be approaching Oahu and Kauai. If the forecast holds true, this would help to slow the forward motion of the system (not so good – increased flooding potential) and steer it west (good – away from the islands).

Uncertainty

The probability of tropical storm conditions continues a gradual downward trend. For Maui leeward waters it’s 34 percent; 8 percent in Hilo; 16 percent in Kailua-Kona and 20 percent near South Point.

Potential Impacts (if the track holds)

Heavy rain and thunderstorms are expected for the Big Island today, potentially causing dangerous flash flooding with excessive runoff and causing possible mud slides and rock slides in steep terrain. Flooding is possible statewide over the weekend. These heavy rain conditions are likely to sweep up the island chain from east to west through the weekend.

Large dangerous surf conditions will impact the eastern end of the Hawaiian islands, spreading westward through the weekend as well. Additional storm surge of 1 -2 feet for southeastern shores is likely.

Winds are expected to increase to 35 mph. Gusts could reach 50 mph or more as the center of Ana passes. Highest winds will be through mountainous terrain, valleys and passes.

The current Big Island forecast calls for 6 to 8 inches of rqain with up to 12 inches along southeast facing slopes

Winds of 25 to 40 mph, gusting to 50 mph, are possible Friday and Saturday.

Seas of 15 to 25 feet are expected. Surf heights up to 20 feet are possible late Friday along the Puna and Kau coastlines during the closest approach. Elevated surf of up to 12 feet is possible along the Kona coasts Saturday.

It’s becoming quite apparent on radar just how big this system is when compared to our land masses in the Hawaiian islands. Slight deviations to the right could have significant negative impacts on the effects we see to our island weather. Slight deviations to the left could similarly have a positive effect on our weather. Closely monitoring the system and the impending conditions as Ana continues to approach is a smart idea.