Marine Weather and Tide Forecast for Kahaluu-Keauhou, HI
April 21, 2025 1:55 AM HST (11:55 UTC) Change Location
![]() | Sunrise 5:56 AM Sunset 6:41 PM Moonrise 1:40 AM Moonset 12:57 PM |
PHZ123 Big Island Leeward Waters- 946 Pm Hst Sun Apr 20 2025
Rest of tonight - Winds variable less than 10 knots west of the big island - .east 15 to 20 knots near south point. Seas 3 to 5 feet. Wave detail: east 3 feet at 5 seconds. Scattered showers.
Monday - Winds variable less than 10 knots west of the big island - .east 15 to 20 knots near south point. Seas 3 to 5 feet. Wave detail: east 3 feet at 4 seconds. Isolated showers.
Monday night - West of the big island, winds variable less than 10 knots, becoming north northwest 7 to 10 knots after midnight. NEar south point, east winds to 15 knots. Seas 3 to 5 feet. Wave detail: east 3 feet at 4 seconds. Scattered showers.
Tuesday - West of the big island, north northwest winds 7 to 10 knots. NEar south point, east winds 15 to 20 knots, veering to east southeast in the afternoon. Seas 4 to 6 feet. Wave detail: southeast 4 feet at 5 seconds and south 3 feet at 17 seconds. Isolated showers.
Tuesday night - Winds variable less than 10 knots west of the big island - .east to 15 knots near south point. Seas 4 to 6 feet. Wave detail: southeast 4 feet at 5 seconds and south 3 feet at 16 seconds. Scattered showers.
Wednesday - West of the big island, winds variable less than 10 knots. NEar south point, east winds to 20 knots, veering to east southeast in the afternoon. Seas 5 to 7 feet. Wave detail: southeast 4 feet at 5 seconds and south 3 feet at 15 seconds. Isolated showers.
Wednesday night - Winds variable less than 10 knots west of the big island - .east to 20 knots near south point. Seas 4 to 6 feet. Wave detail: southeast 4 feet at 5 seconds. Isolated showers.
Thursday - West of the big island, winds variable less than 10 knots, becoming north northwest 7 to 10 knots in the afternoon, then becoming variable less than 10 knots. NEar south point, east winds 15 to 20 knots. Seas 4 to 6 feet. Wave detail: southeast 4 feet at 5 seconds. Isolated showers in the morning. Isolated showers through the day.
Friday - Winds variable less than 10 knots west of the big island - .east 15 to 20 knots near south point. Seas 4 to 6 feet. Wave detail: southeast 4 feet at 5 seconds. Isolated showers through the day.
PHZ100 946 Pm Hst Sun Apr 20 2025
Synopsis for hawaiian coastal waters - High pressure far northeast of hawaii will produce moderate to locally fresh easterly trade winds into Monday. On Tuesday, a surface low will develop about 500 nm northwest of kauai, causing moderate winds to veer out of the south across most waters, with moderate to fresh southeast winds developing around the big island and maui. The low will bring a chance of Thunderstorms across the western end of the island chain. The low will lift northward on Friday.
7 Day Forecast for Marine Location Near Kahaluu-Keauhou, HI

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Kailua Kona Click for Map Mon -- 01:39 AM HST Moonrise Mon -- 06:01 AM HST Sunrise Mon -- 06:03 AM HST 0.13 feet Low Tide Mon -- 11:30 AM HST 0.72 feet High Tide Mon -- 12:57 PM HST Moonset Mon -- 04:08 PM HST 0.37 feet Low Tide Mon -- 06:44 PM HST Sunset Mon -- 11:15 PM HST 1.84 feet High Tide Tide / Current data from XTide NOT FOR NAVIGATION |   |
Kailua Kona, Big Island, Hawaii, Tide feet
12 am |
1.7 |
1 am |
1.4 |
2 am |
1 |
3 am |
0.7 |
4 am |
0.4 |
5 am |
0.2 |
6 am |
0.1 |
7 am |
0.2 |
8 am |
0.3 |
9 am |
0.5 |
10 am |
0.6 |
11 am |
0.7 |
12 pm |
0.7 |
1 pm |
0.6 |
2 pm |
0.5 |
3 pm |
0.4 |
4 pm |
0.4 |
5 pm |
0.4 |
6 pm |
0.6 |
7 pm |
0.8 |
8 pm |
1.1 |
9 pm |
1.5 |
10 pm |
1.7 |
11 pm |
1.8 |
Kawaihae Click for Map Mon -- 01:40 AM HST Moonrise Mon -- 06:00 AM HST Sunrise Mon -- 06:26 AM HST 0.27 feet Low Tide Mon -- 11:52 AM HST 0.80 feet High Tide Mon -- 12:56 PM HST Moonset Mon -- 04:15 PM HST 0.50 feet Low Tide Mon -- 06:43 PM HST Sunset Mon -- 11:35 PM HST 2.02 feet High Tide Tide / Current data from XTide NOT FOR NAVIGATION |   |
Kawaihae, Big Island, Hawaii, Tide feet
12 am |
1.9 |
1 am |
1.6 |
2 am |
1.3 |
3 am |
0.9 |
4 am |
0.6 |
5 am |
0.4 |
6 am |
0.3 |
7 am |
0.3 |
8 am |
0.4 |
9 am |
0.5 |
10 am |
0.7 |
11 am |
0.8 |
12 pm |
0.8 |
1 pm |
0.8 |
2 pm |
0.7 |
3 pm |
0.6 |
4 pm |
0.5 |
5 pm |
0.5 |
6 pm |
0.7 |
7 pm |
0.9 |
8 pm |
1.2 |
9 pm |
1.5 |
10 pm |
1.8 |
11 pm |
2 |
Area Discussion for Honolulu, HI
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FXHW60 PHFO 210642 AFDHFO
Area Forecast Discussion National Weather Service Honolulu HI 842 PM HST Sun Apr 20 2025
SYNOPSIS
Light to moderate trade winds are expected Monday with some showers focused over windward and mauka areas, although some interior showers will also be possible. A deepening low to the far northwest of the state will sink southward over the next several days. This will disrupt the trade flow by Tuesday with southerly winds, and introduce higher chances for showers across the state. The threat for heavy rain and isolated thunderstorms will likely increase over Kauai Tuesday through Wednesday.
DISCUSSION
No changes to the forecast this evening, and not expecting to make any significant changes with the morning package.
An upper level trough shifting away from the state is helping to stabilize the airmass over the islands. While trade winds have filtered back in at the surface due to a surface ridge to the far north, expect lighter trade winds on Monday. This will allow for some localized land and sea breezes to set up, which in turn means a few interior showers Monday afternoon. However the more stable airmass should limit rainfall totals Monday.
A surface low pressure system far north-northwest of the islands has an upper level low associated with it, and this will be the focus for our next weather event. This system is expected to strengthen as it sinks southward over the next few days, bringing with it another round of unstable and wet weather to the islands.
There is good agreement with the GFS and ECMWF that both the surface and upper level lows will remain to the west of the islands. This will likely mean that Kauai is most likely to experience the heavy showers and possible thunderstorms that will be associated with the system. However southerly winds on the east side of the system will bring increased moisture over all the islands. There is good agreement with these models that precipitable water (PW) will exceed 1.5 inches, which is well above normal for this time of year. The models are also in good agreement with 500 mb temperatures around Kauai and Oahu reaching -10C, which is normal for this time of year. Despite upper level temperatures near normal, the well above normal PW will help to fuel heavier showers.
With this event, we expect a large gradient in rainfall between the western end and the eastern end of the state. The Island of Kauai will be the closest to the low pressure system and should see the greatest rainfall from this event. Heavy rain will be the main concern and a Flood Watch may be needed for Kauai around the Tuesday through Wednesday time frame. With the latest QPF ensemble guidance coming into better agreement, the main moisture axis will likely stay just west of Kauai. Nonetheless, it would only take a slight shift more eastward for Kauai to be under the main moisture band. Even if the main band of rain stays just west, heavy downpours with isolated thunderstorms should be expected over Kauai during this time. For rest of the state, scattered showers with some moderate rainfall totals will be possible with higher rainfall amounts likely around Oahu. By Friday, the upper level low should lift further north and away from the state which should bring the return of stable conditions, although trade winds may not return until later in the weekend.
AVIATION
Moderate trades will persist through this evening and weaken slightly heading into Monday. Low cigs and SHRA expected of mauka and windward locations. Winds will be light enough to support isol sea/land breeze development that will bring additional SHRA to some leeward and interior areas during the afternoon hours through tomorrow and clearing of these areas overnight. MVFR/IFR conds will be possible in any SHRA, otherwise VFR should prevail.
AIRMET Sierra for mtn obsc is in effect for windward sections of Oahu through Maui and for the entire Big Island.
MARINE
Moderate to locally fresh easterly trade winds will ease on Monday and veer southeast as a high centered far northeast of Hawaii weakens and a surface trough develops about 500 nm northwest of Kauai. On Tuesday, the trough will deepen into a low about 400 nm northwest of Kauai, and moderate winds will veer out of the south across most waters, while moderate to fresh southeast winds develop around the Big Island and Maui through Thursday.
The low will also bring a chance of heavy showers and thunderstorms, mainly over the western end of the island chain.
The low will lift northward on Friday, allowing winds to back out of the southeast statewide.
Small surf will prevail along north shores through much of the week. Near shore buoys are show a decline in 14-12 second energy from a small north northwest swell today and will continue to fade into Monday. Monday night, another tiny northwest swell will fill in and maintain small surf into Wednesday. Minimal surf is expected later Wednesday through Friday, followed by another small pulse of northwest swell next weekend.
South shore surf will be near April average through Monday, followed by a larger south-southwest swell on Tuesday. The PacIOOS Kaumalapau buoy has been showing the current swell holding at around 2 feet 15 seconds this afternoon, with little change expected Monday. A larger swell will arrive on Tuesday, pushing surf along south facing shores above summer average. The swell will hold through Wednesday, then decline Thursday and Friday.
Small surf along east facing shores will be near current heights through Monday, then drop on Tuesday as southerly winds develop.
HFO WATCHES/WARNINGS/ADVISORIES
None.
Area Forecast Discussion National Weather Service Honolulu HI 842 PM HST Sun Apr 20 2025
SYNOPSIS
Light to moderate trade winds are expected Monday with some showers focused over windward and mauka areas, although some interior showers will also be possible. A deepening low to the far northwest of the state will sink southward over the next several days. This will disrupt the trade flow by Tuesday with southerly winds, and introduce higher chances for showers across the state. The threat for heavy rain and isolated thunderstorms will likely increase over Kauai Tuesday through Wednesday.
DISCUSSION
No changes to the forecast this evening, and not expecting to make any significant changes with the morning package.
An upper level trough shifting away from the state is helping to stabilize the airmass over the islands. While trade winds have filtered back in at the surface due to a surface ridge to the far north, expect lighter trade winds on Monday. This will allow for some localized land and sea breezes to set up, which in turn means a few interior showers Monday afternoon. However the more stable airmass should limit rainfall totals Monday.
A surface low pressure system far north-northwest of the islands has an upper level low associated with it, and this will be the focus for our next weather event. This system is expected to strengthen as it sinks southward over the next few days, bringing with it another round of unstable and wet weather to the islands.
There is good agreement with the GFS and ECMWF that both the surface and upper level lows will remain to the west of the islands. This will likely mean that Kauai is most likely to experience the heavy showers and possible thunderstorms that will be associated with the system. However southerly winds on the east side of the system will bring increased moisture over all the islands. There is good agreement with these models that precipitable water (PW) will exceed 1.5 inches, which is well above normal for this time of year. The models are also in good agreement with 500 mb temperatures around Kauai and Oahu reaching -10C, which is normal for this time of year. Despite upper level temperatures near normal, the well above normal PW will help to fuel heavier showers.
With this event, we expect a large gradient in rainfall between the western end and the eastern end of the state. The Island of Kauai will be the closest to the low pressure system and should see the greatest rainfall from this event. Heavy rain will be the main concern and a Flood Watch may be needed for Kauai around the Tuesday through Wednesday time frame. With the latest QPF ensemble guidance coming into better agreement, the main moisture axis will likely stay just west of Kauai. Nonetheless, it would only take a slight shift more eastward for Kauai to be under the main moisture band. Even if the main band of rain stays just west, heavy downpours with isolated thunderstorms should be expected over Kauai during this time. For rest of the state, scattered showers with some moderate rainfall totals will be possible with higher rainfall amounts likely around Oahu. By Friday, the upper level low should lift further north and away from the state which should bring the return of stable conditions, although trade winds may not return until later in the weekend.
AVIATION
Moderate trades will persist through this evening and weaken slightly heading into Monday. Low cigs and SHRA expected of mauka and windward locations. Winds will be light enough to support isol sea/land breeze development that will bring additional SHRA to some leeward and interior areas during the afternoon hours through tomorrow and clearing of these areas overnight. MVFR/IFR conds will be possible in any SHRA, otherwise VFR should prevail.
AIRMET Sierra for mtn obsc is in effect for windward sections of Oahu through Maui and for the entire Big Island.
MARINE
Moderate to locally fresh easterly trade winds will ease on Monday and veer southeast as a high centered far northeast of Hawaii weakens and a surface trough develops about 500 nm northwest of Kauai. On Tuesday, the trough will deepen into a low about 400 nm northwest of Kauai, and moderate winds will veer out of the south across most waters, while moderate to fresh southeast winds develop around the Big Island and Maui through Thursday.
The low will also bring a chance of heavy showers and thunderstorms, mainly over the western end of the island chain.
The low will lift northward on Friday, allowing winds to back out of the southeast statewide.
Small surf will prevail along north shores through much of the week. Near shore buoys are show a decline in 14-12 second energy from a small north northwest swell today and will continue to fade into Monday. Monday night, another tiny northwest swell will fill in and maintain small surf into Wednesday. Minimal surf is expected later Wednesday through Friday, followed by another small pulse of northwest swell next weekend.
South shore surf will be near April average through Monday, followed by a larger south-southwest swell on Tuesday. The PacIOOS Kaumalapau buoy has been showing the current swell holding at around 2 feet 15 seconds this afternoon, with little change expected Monday. A larger swell will arrive on Tuesday, pushing surf along south facing shores above summer average. The swell will hold through Wednesday, then decline Thursday and Friday.
Small surf along east facing shores will be near current heights through Monday, then drop on Tuesday as southerly winds develop.
HFO WATCHES/WARNINGS/ADVISORIES
None.
Stations | Dist | Age | Wind | Air | Water | Waves | inHg | DewPt |
KWHH1 | 30 mi | 55 min | NE 1.9G | 75°F | 79°F | 30.01 | ||
ILOH1 - 1617760 - Hilo, HI | 49 mi | 55 min | SSW 1G | |||||
KLIH1 - 1615680 - Kahului Bay, Maui, HI | 93 mi | 55 min | E 8.9G | 74°F | 78°F | 30.06 |
Wind History for Kawaihae, HI
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Airport Reports
Link to 1 hour of 5 minute data for PHKO
Terminal Aerodrome Forecast (TAF) for PHKO
Wind History Graph: HKO
(wind in knots)GEOS Local Image of Hawaii
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