Hilo

Tonight: Tropical storm conditions expected. Showers and isolated thunderstorms. Locally heavy rainfall possible. Lows 67 to 74 near the shore to 59 to 65 at 4000 feet. East winds 10 to 30 mph. Gusts up to 55 mph decreasing to 45 mph after midnight. Chance of rain near 100 percent.

Sunday: Breezy. Showers and isolated thunderstorms in the morning, then showers in the afternoon. Locally heavy rainfall possible in the afternoon. Highs 78 to 86 near the shore to around 66 at 4000 feet. East winds 10 to 20 mph. Chance of rain near 100 percent.

Sunday Night: Breezy and showers. Lows 65 to 73 near the shore to 57 to 62 at 4000 feet. East winds 10 to 20 mph. Chance of rain near 100 percent.

Kona

Tonight: Tropical storm conditions expected. Cloudy with numerous showers and isolated thunderstorms. Locally heavy rainfall possible. Lows around 76 near the shore to 54 to 59 near 5000 feet. Northeast winds up to 30 mph increasing to east 20 to 30 mph after midnight. Gusts up to 60 mph. Chance of rain 70 percent.

Sunday: Tropical storm conditions possible. Cloudy. Numerous showers and isolated thunderstorms in the morning, then showers and isolated thunderstorms in the afternoon. Locally heavy rainfall possible. Highs 85 to 90 near the shore to 67 to 72 near 5000 feet. East winds up to 30 mph with gusts to 55 mph shifting to the west up to 15 mph in the afternoon. Chance of rain 90 percent.

Sunday Night: Cloudy. Numerous showers in the evening, then scattered showers after midnight. Locally heavy rainfall possible in the evening. Lows around 76 near the shore to around 56 near 5000 feet. Light winds. Gusts up to 35 mph in the evening. Chance of rain 70 percent.

Waimea

Tonight: Tropical storm conditions expected. Showers and isolated thunderstorms. Locally heavy rainfall possible. Lows 67 to 74 near the shore to 60 to 67 near 3000 feet. East winds 20 to 45 mph decreasing to 10 to 45 mph after midnight. Gusts up to 75 mph decreasing to 70 mph after midnight. Chance of rain near 100 percent.

Sunday: Tropical storm conditions expected. Showers and isolated thunderstorms. Locally heavy rainfall possible in the afternoon. Highs 64 to 86. East winds 10 to 40 mph with gusts to 60 mph decreasing to up to 30 mph with gusts to 50 mph in the afternoon. Chance of rain near 100 percent.

Sunday Night: Tropical storm conditions possible. Showers. Locally heavy rainfall possible in the evening. Lows 66 to 74 near the shore to 57 to 65 near 3000 feet. East winds up to 30 mph with gusts to 50 mph becoming 10 to 20 mph after midnight. Chance of rain near 100 percent.

Kohala

Tonight: Tropical storm conditions expected. Showers and isolated thunderstorms. Locally heavy rainfall possible. Lows 67 to 74 near the shore to 60 to 67 near 3000 feet. East winds 20 to 45 mph decreasing to 10 to 45 mph after midnight. Gusts up to 75 mph decreasing to 70 mph after midnight. Chance of rain near 100 percent.

Sunday: Tropical storm conditions expected. Showers and isolated thunderstorms. Locally heavy rainfall possible in the afternoon. Highs 64 to 86. East winds 10 to 40 mph with gusts to 60 mph decreasing to up to 30 mph with gusts to 50 mph in the afternoon. Chance of rain near 100 percent.

Sunday Night: Tropical storm conditions possible. Showers. Locally heavy rainfall possible in the evening. Lows 66 to 74 near the shore to 57 to 65 near 3000 feet. East winds up to 30 mph with gusts to 50 mph becoming 10 to 20 mph after midnight. Chance of rain near 100 percent.

South Big Island

Tonight: Tropical storm conditions. Cloudy. Numerous showers and isolated thunderstorms in the evening, then showers and isolated thunderstorms after midnight. Locally heavy rainfall possible. Lows around 76 near the shore to around 57 near 5000 feet. Northeast winds 15 to 45 mph increasing to east 30 to 50 mph after midnight. Gusts up to 70 mph. Chance of rain 90 percent.

Sunday: Tropical storm conditions expected. Cloudy with showers and isolated thunderstorms. Locally heavy rainfall possible. Highs around 86 near the shore to around 69 near 5000 feet. East winds 25 to 40 mph with gusts to 65 mph decreasing to 20 to 30 mph with gusts to 50 mph in the afternoon. Chance of rain 90 percent.

Sunday Night: Tropical storm conditions possible. Cloudy. Showers in the evening, then numerous showers after midnight. Locally heavy rainfall possible in the evening. Lows around 75 near the shore to around 56 near 5000 feet. East winds 20 to 30 mph decreasing to 10 to 20 mph after midnight. Chance of rain 90 percent.

Puna

Tonight: Tropical storm conditions expected. Showers and isolated thunderstorms. Locally heavy rainfall possible. Lows 67 to 74 near the shore to 59 to 65 at 4000 feet. East winds 10 to 30 mph. Gusts up to 55 mph decreasing to 45 mph after midnight. Chance of rain near 100 percent.

Sunday: Breezy. Showers and isolated thunderstorms in the morning, then showers in the afternoon. Locally heavy rainfall possible in the afternoon. Highs 78 to 86 near the shore to around 66 at 4000 feet. East winds 10 to 20 mph. Chance of rain near 100 percent.

Sunday Night: Breezy and showers. Lows 65 to 73 near the shore to 57 to 62 at 4000 feet. East winds 10 to 20 mph. Chance of rain near 100 percent.

Waikoloa

Tonight: Tropical storm conditions expected. Scattered showers and isolated thunderstorms in the evening, then showers and isolated thunderstorms after midnight. Locally heavy rainfall possible. Lows around 78 near the shore to around 61 above 4000 feet. East winds up to 45 mph with gusts to 75 mph. Chance of rain near 100 percent.

Sunday: Cloudy and breezy. Showers and isolated thunderstorms in the morning, then numerous showers and isolated thunderstorms in the afternoon. Locally heavy rainfall possible in the afternoon. Highs 84 to 90 near the shore to 67 to 74 above 4000 feet. Northeast winds up to 25 mph. Gusts up to 60 mph decreasing to 50 mph in the afternoon. Chance of rain 90 percent.

Sunday Night: Cloudy and breezy. Numerous showers in the evening, then scattered showers after midnight. Locally heavy rainfall possible in the evening. Lows around 77 near the shore to around 59 above 4000 feet. East winds up to 25 mph becoming 10 to 15 mph after midnight. Gusts up to 45 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

The Central Pacific Hurricane Center continues to closely monitor Tropical Storm Hone southeast of the Big Island moving westward. On its current track, Hone will brush past the southern slopes of the Big Island tonight into Sunday morning bringing the potential for heavy rainfall, damaging winds, and large surf. Expect strong and gusty easterly winds and periods of heavy showers to continue through Monday as Hone passes south of the smaller islands. A brief return of moderate to breezy trade winds is expected late Monday through Wednesday as Hone continues on its westward journey moving away from the island chain. Tropical Cyclone Gilma far east of the state will weaken as it approaches the Hawaii Region by the end of next week, possibly bringing more rainfall to the islands.

Discussion

High pressure far north of the Hawaiian Islands and Tropical Storm Hone passing near the southern slopes of the Big Island will keep strong and gusty winds in the forecast through Monday. Cloud bands moving in ahead of Hone will continue to produce periods of showers over the Big Island and windward and mauka areas of the smaller islands.
Forecast confidence in Hone impacting our local weather remains high. The latest Central Pacific Hurricane Center forecast keeps Hone a tropical storm as it passes south of the islands. Based on the current forecast track, strong and gusty winds associated with Hone will continue to impact the Big Island, with widespread gusts up to 50 mph likely through early Sunday. The strongest gusts are expected around South Point/Ka Lae, as well as downslope from Mauna Kea, Mauna Loa, the Kohala Mountains, and the Humuula Saddle, which could see localized gusts as high as 60 mph. A Tropical Storm Warning remains in effect for the Big Island.
Winds will continue to increase across the rest of the state tonight into Sunday. Strong downslope winds will continue over leeward slopes through Sunday night. Wind gusts to 50 mph remain possible and a Wind Advisory remains in effect for these areas. A Wind Advisory for the Haleakala Summit also remains in effect, with gusts to 60 mph possible tonight and Sunday.
Deep tropical moisture associated with Hone continues to move into windward portions of the Big Island, with additional moisture expected to move in tonight. Windward areas of the Big Island have already seen 2 to 4 inches of rainfall from Hone, with moderate to heavy showers expected to move ashore over the next several hours. This moisture will expand westward to all islands through early next week as Hone passes to the south of the state, increasing the potential for heavy rainfall statewide. As rainbands associated with Tropical Storm Hone move into each island, heavy showers and isolated thunderstorms will increase the threat for localized flash flooding. A Flood Watch remains in effect for the Big Island. Storm total rainfall estimates for the Big Island will range from 6 to 12 inches, with locally higher amounts possible. Smaller islands should see rainfall amounts from 2 to 4 inches. The higher amounts in these ranges will fall along windward mountain slopes of each island.
As the moisture associated with Hone fills in across the state expect relative humidity levels to increase. This increase in humidity will decrease the threat of elevated fire weather concerns so the Red Flag Warning for leeward areas of the smaller islands will expire at 6 PM.
A brief return of moderate to breezy trade winds is expected late Monday through Wednesday of next week as Hone tracks away from the state and Tropical Cyclone Gilma approaches the region from the east. Forecast confidence, with regards to impacts to our local weather, remains very low late next week due to significant differences shown between the various sources of guidance as Gilma approaches the region by the end of next week.
For further details on Hone's development, please refer to the latest forecast issued by the Central Pacific Hurricane Center at www.hurricanes.gov.
Note that public and marine forecasts from WFO Honolulu will be updated on a modified schedule, in conjunction with the latest Central Pacific Hurricane Center forecast issued at 5 AM/PM and 11 AM/PM HST.

Aviation

Tropical Storm Hone currently sitting around 125 miles southeast of Hilo is going to be the main focus throughout the weekend for the islands as it continues its westward trajectory. As it approaches and passes just south of the Big Island tonight into tomorrow morning, expect widespread visibilities less than a mile and ceilings below 1000 ft for the east facing portions of the Big Island. Winds above 40 kt are already being observed over portions of the Big Island with higher winds expected tonight into tomorrow. Additionally, thunderstorms are also possible for the Big Island through tomorrow morning.
For the rest of the islands, expect increasing clouds and showers tonight through tomorrow with widespread MVFR conditions for windward and mountain areas. Towering cumulus clouds in Hone's outer band could bring isolated IFR conditions but is not expected to be widespread. Winds are expected to be strong over most areas with gusts over 40 kt.
AIRMET Sierra for IFR conditions is in effect for visibilities below 3 miles and ceilings below 1000 ft for windward portions of the Big Island. This AIRMET will likely remain through tomorrow morning. AIRMET Sierra remains in effect for mtn obsc for all islands and will also likely remain through at least tomorrow morning.
AIRMET Tango for strong surface winds in excess of 40 kt for the Big Island and 30 kt for the rest of the islands is in effect. AIRMET Tango remains in effect for mod low-level turb blw 080 downwind of island terrain. These AIRMETs will most likely be needed through tomorrow.
As Tropical Storm Hone approaches the islands, aviation interests should closely monitor updates to TC SIGMET Whiskey as well as the latest forecast from Central Pacific Hurricane Center.

Marine

Tropical Storm Hone continues to move westward at 14 mph and is located at 18.0N 154.4W as of 5 PM HST this evening. TS Hone will be making its closest approach to the Big Island during the next 12 hours and a Tropical Storm Warning remains in effect for the surrounding Big Island waters. With TS Hone expected to pass just south of islands and a strong high far north of the state, the pressure gradient with tighten over the state and will result in the trade winds strengthening tonight into Sunday. Gale Warnings are in effect for the windier waters around Maui County and a Small Craft Advisory is in effect for all remaining waters.
Large and disorganized short and medium period swells associated with Tropical Storm Hone will likely peak this evening then steadily fade late tonight. Dangerous surf is expected along east and southeast facing shores of the Big Island during this time. With the trade winds strengthening over the smaller islands tonight into Sunday, surf along east facing shores of the smaller islands should steadily increase tonight and peak on Sunday at advisory thresholds. High Surf Warning remains in effect for east and southeast facing exposures of Big Island and a High Surf Advisory is in effect for east facing shores of the smaller islands.
Surf along north facing shores is expected to remain tiny over the next several days, aside from some wind swell wrap. Surf along south and southeast facing shores of the smaller islands should see an increase Sunday into Monday as Tropical Storm Hone passes south of the island chain. Low confidence in actual surf height values for south and southeast facing exposures due to it depending on the strength of Hone as it passes south.

Fire weather

Strong downslope winds will continue through Sunday night. However, as moisture associated with Hone fills in across the state this evening expect relative humidity levels to increase. This increase in humidity will decrease the threat of elevated fire weather concerns so the Red Flag Warning for leeward areas of the smaller islands will expire at 6 PM.

HFO Watches/Warnings/Advisories

Red Flag Warning until 6 PM HST this evening for leeward areas of Niihau, Kauai, Oahu, Molokai, Lanai, Maui, Molokai.
Wind Advisory until 6 AM HST Monday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Central Oahu, Waianae Mountains, Lanai Mauka, Kahoolawe, Maui Leeward West, Haleakala Summit, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Koolau Leeward, Molokai West, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley North, Maui Central Valley South, South Maui/Upcountry, South Haleakala.
High Surf Advisory until 6 PM HST Sunday for Olomana, Maui Windward West, Kauai East, East Honolulu, Koolau Windward, Molokai Windward, Molokai Southeast, Windward Haleakala, Kipahulu, South Haleakala.
Flood Watch through Monday evening for Big Island,
Tropical Storm Warning for Big Island,
High Surf Warning until 6 AM HST Sunday for Big Island Southeast, Big Island East, Big Island North.
Tropical Storm Warning for Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 5 PM HST Monday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Oahu Windward Waters, Maui County Windward Waters.
Small Craft Advisory until 6 AM HST Monday for Kauai Channel, Oahu Leeward Waters, Kaiwi Channel, Maui County Leeward Waters.
Gale Warning until 6 PM HST Sunday for Maalaea Bay, Pailolo Channel.

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Data Courtesy of NOAA.gov