Sunrise 5:46 AM   Sunset 6:47 PM Moonrise 5:25 AM   Moonset 6:49 PM

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PHZ123 Big Island Leeward Waters- 911 Am Hst Tue May 7 2024
.small craft advisory in effect through late this afternoon - .
Rest of today - Northwest winds 7 to 10 knots west of the big island - .east to 25 knots near south point. Seas 5 to 7 feet. Wave detail: east 5 feet at 5 seconds. Tonight - West of the big island, west winds 7 to 10 knots. NEar south point, east winds 15 to 20 knots, becoming to 20 knots after midnight. Seas 4 to 6 feet. Wave detail: east 5 feet at 6 seconds. Isolated showers. Wednesday - West of the big island, winds variable less than 10 knots, becoming northwest 7 to 10 knots in the afternoon. NEar south point, east winds to 15 knots. Seas 3 to 5 feet. Wave detail: east southeast 4 feet at 5 seconds. Scattered showers. Wednesday night - Winds variable less than 10 knots west of the big island - .east to 15 knots near south point. Seas 3 to 5 feet. Wave detail: east 3 feet at 4 seconds. Scattered showers. Thursday - West of the big island, north northwest winds 7 to 10 knots in the morning, becoming variable less than 10 knots. NEar south point, east winds 10 to 15 knots. Seas 3 to 5 feet. Wave detail: east southeast 3 feet at 4 seconds. Isolated showers. Thursday night - West of the big island, winds variable less than 10 knots. NEar south point, east winds 10 to 15 knots, backing to east northeast after midnight. Seas 3 to 5 feet. Isolated showers in the evening, then scattered showers after midnight. Friday - West of the big island, winds variable less than 10 knots. NEar south point, east northeast winds to 10 knots, veering to east southeast in the afternoon, then becoming variable less than 10 knots in the evening, becoming east northeast 7 to 10 knots after midnight. Seas 3 to 4 feet. Scattered showers through the night. Isolated Thunderstorms. Numerous showers through the day. Saturday - Winds variable less than 10 knots west of the big island - .east 10 to 15 knots near south point. Seas 3 to 5 feet. Numerous showers with isolated Thunderstorms.
winds and seas higher in and near tstms.

PHZ100 911 Am Hst Tue May 7 2024
Synopsis for hawaiian coastal waters - High pressure northeast of the state will move away easing trade wind speeds. A trough developing north of the islands on Wednesday will drift near or over the area Thursday through Saturday, further easing winds. An upper low will move across the islands bringing unstable weather Friday into the weekend.

FXHW60 PHFO 072004 AFDHFO

Area Forecast Discussion National Weather Service Honolulu HI 1004 AM HST Tue May 7 2024

SYNOPSIS
A low pressure system moving into the Central Pacific basin north of Hawaii will weaken the subtropical ridge and keep light to moderate trade winds in the forecast this week. An unstable environment will bring the threat for flash flooding and isolated thunderstorms late this week and possibly into the weekend as an upper level low moves through the state.

DISCUSSION
The trade winds have weakened a notch from yesterday and for rest of the day today, we should see moderate trades with some scattered showers over windward areas and the kona slopes of the Big Island this afternoon. The trades may be light enough for select leeward areas, where we could possibly see some isolated showers this afternoon due to the sea breezes. On the summits of the Big Island, we do have a High Wind Warning in effect through this evening and wind observations are showing wind gusts of over 70 mph. The winds should taper off on Wednesday, but the High Wind Warning will probably need to be extended through tonight.

Starting Wednesday, the trades will weaken further as a surface trough develops north of the state. Light to moderate trades are expected across the state with wide spread sea breezes developing during the day time, which will allow for scattered showers over interior and leeward areas during the afternoon.

Starting Thursday, the atmosphere will begin to change as an upper level trough approaches the state. The surface winds will continue to remain light with daytime sea breezes developing. Temperatures aloft will begin to cool, which will bring instability over the state. With the added instability and some low level moisture, showers should increase during the afternoon on Thursday. Some of the showers can be locally heavy and the most likely area for some downpours looks to be over windward and interior areas.

A deep upper level trough will continue to approach the state Thursday night with a cold cut off low developing over or very close to the state by Friday afternoon. 500 mb temperatures on the ECMWF is showing around -14C for Lihue, which is very unusual for this time of year. This will produce a very unstable weather pattern for Friday and will bring the threat for flash flooding and isolated thunderstorms to the state. It is too early to tell exactly where we could see the heavier showers and thunderstorms and it will highly depend on the position of the upper level low.
Latest GFS and ECMWF has the upper level low centered around the western half of the state Friday afternoon. This will cause the most favorable area for thunderstorms and heavy rain to be over the eastern half of the state. But if the upper level low was to shift slightly more west, Oahu and Kauai could also be under the same threat. But for now, we are looking at the possibility of intense rain showers and isolated thunderstorms starting as early as Friday and most likely between Friday afternoon through the evening for the entire state. A Flood Watch will likely be issued sometime in the coming days.

For the weekend, there is still quite a bit of uncertainty on how quickly the upper level low will move through the state (from west to east) with the latest global models trending slower. Although the models have trended slower, there is fairly good agreement with the upper level low being east of Kauai by Saturday. The threat for flash flooding and isolated thunderstorms should decrease from west to east as the upper level low slowly progresses eastward. At this time, the eastern half of the state, sees the greatest chance for some unsettled weather this weekend.



AVIATION
Moderate trade winds will prevail across the island chain today, then ease up a bit tonight especially over the western islands.
Low clouds and showers will continue to favor windward and mauka areas, and be most active during the overnight hours. Brief MVFR CIG and VIS are likely in passing showers, otherwise VFR conditions are expected to prevail through at least early evening.

AIRMET Sierra for mountain obscuration has been canceled, but conditions could redevelop along windward slopes late tonight or early Wednesday.

MARINE
A Small Craft Advisory (SCA) remains in effect for the typically windy waters around the Big Island and Maui County through this afternoon due to fresh to strong winds. The winds will slowly ease today as high pressure northeast of the state moves further away.

A surface trough will form north of the state Wednesday. As this feature drifts southward near or over the islands Thursday into Saturday, the trade winds will weaken further, and chances for heavy showers will increase through the weekend. An upper low will move across the island chain Friday through Sunday and bring a slight chance of thunderstorms.

Near shore buoys are showing signs of fading energy in the 12 to 14 sec range suggesting the current south swell is slowly beginning to fade today into Wednesday. Forerunners from a larger and longer lived south-southwest swell will arrive Wednesday, and surf is expected rise near, or to, the High Surf Advisory level during the peak of the swell Thursday and Friday. This swell will gradually decline through the weekend.

A small northwest swell of around 3 feet will peak today, then decline Wednesday. Wind driven waves will gradually decline to around May average today, then drop to below average for the rest of the week.

HFO WATCHES/WARNINGS/ADVISORIES
High Wind Warning until 6 PM HST this evening for Big Island Summits.

Small Craft Advisory until 6 PM HST this evening for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.

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Napoopoo
Click for Map
Tue -- 02:42 AM HST     0.94 feet High Tide
Tue -- 05:26 AM HST     Moonrise
Tue -- 05:51 AM HST     Sunrise
Tue -- 08:39 AM HST     -0.45 feet Low Tide
Tue -- 03:51 PM HST     2.28 feet High Tide
Tue -- 05:24 PM HST     New Moon
Tue -- 06:48 PM HST     Sunset
Tue -- 06:49 PM HST     Moonset
Tue -- 10:56 PM HST     0.07 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Napoopoo, Kealakekua Bay, Hawaii Island, Hawaii, Tide feet

Kailua Kona
Click for Map
Tue -- 02:42 AM HST     1.03 feet High Tide
Tue -- 05:26 AM HST     Moonrise
Tue -- 05:51 AM HST     Sunrise
Tue -- 08:36 AM HST     -0.32 feet Low Tide
Tue -- 03:45 PM HST     2.33 feet High Tide
Tue -- 05:24 PM HST     New Moon
Tue -- 06:49 PM HST     Sunset
Tue -- 06:49 PM HST     Moonset
Tue -- 10:43 PM HST     0.15 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Kailua Kona, Big Island, Hawaii, Tide feet

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