Marine Weather and Tides
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.
|Sunrise 5:52AM||Sunset 7:01PM||Saturday July 22, 2017 12:52 AM HST (10:52 UTC)||Moonrise 5:12AM||Moonset 6:39PM||Illumination 2%|
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|PHZ122 Big Island Windward Waters- 930 Pm Hst Fri Jul 21 2017 |
Rest of tonight..East winds 15 knots. Wind waves 3 feet. East swell 6 feet. Scattered showers.
Saturday..East winds 15 knots. Wind waves 3 feet. East swell 6 feet. Scattered showers.
Saturday night..East winds 10 knots. Wind waves 3 feet. East swell 5 feet. Scattered showers.
Sunday..East winds 15 knots. Wind waves 3 feet in the morning then 2 feet or less. East swell 5 feet. Scattered showers.
Sunday night..East winds 10 knots. Wind waves 2 feet or less. East swell 4 feet. Scattered showers.
Monday..East winds 10 knots. Wind waves 2 feet or less. East swell 3 feet in the morning. Scattered showers.
Monday night..East winds 10 knots. Wind waves 3 feet. Scattered showers.
Tuesday..East winds 15 knots. Wind waves 4 feet. East swell 3 to 4 feet. Scattered showers.
Wednesday..Northeast winds 20 knots. Wind waves 4 feet. East swell 4 feet. Scattered showers.
|PHZ100 930 Pm Hst Fri Jul 21 2017 |
Synopsis for hawaiian coastal waters.. Surface high pressure far north of the state will maintain moderate to locally strong trade winds through Saturday morning. The trades are expected to ease thereafter as the remnants of tropical depression fernanda approach the area. East swells from fernanda will continue to spread across most of the coastal waters into early next week.
7 Day Forecast for Marine Location Near Wainaku, HIHourly EDIT Help
Area Discussion for -  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxhw60 phfo 220703 cca|
area forecast discussion... Corrected
national weather service honolulu hi
903 pm hst Fri jul 21 2017
An unsettled period is in the forecast for this weekend, and into
early next week as an upper level trough interacts with low level
moisture riding in with the trades, and then with deeper tropical
moisture associated with weakening and dissipating tropical storm
fernanda early next week. Drier weather with lower humidity and
strong trades will return by midweek.
A deepening upper level trough is currently in the works over the
main hawaiian islands. This will result in a weaker inversion area
wide, which will allow moisture currently capped at 10 to 13k
feet, to rise to 15 to 20 kt feet by Saturday afternoon. The air
mass will be unstable enough to support a thunderstorm or two over
the higher terrain of the big island Saturday afternoon as well.
currently, satellite imagery shows a blob of low clouds and
embedded showers moving through the main hawaiian islands.
Some what of a thinner cloud mass and a lower precipitable water
follows close behind upwind of the smaller islands. Radar is
picking up scattered showers favoring the windward and mountain
areas of most islands. Off and on again sprinkles are reaching
deep into the leeward areas of the smaller islands. Isolated
showers are also present just off the kona coast on the big
island. This somewhat showery pattern should hold through at least
As for tropical storm fernanda, it is located just over 665 miles
e of hilo this evening. It is moving W at 8 mph. It is expected
to continue to weaken as it moves in our general direction,
becoming a remnant low and then a trough as it moves near or just
n of maui county on Monday.
The GFS is suggesting a pocket of lower pw's, or drier air mass,
to briefly affect the islands Saturday night and Sunday morning,
before the arrival of the deep tropical air mass late Sunday.
This is a good legitimate point which will take into consideration.
Current forecast calls for a showery weather Saturday night
through Sunday with the potential for locally heavy showers
Up to Sunday, the trade winds will be modest in speed, but will
turn lighter on Monday. The deep tropical moisture from dying
fernanda should be bleeding onto the big island as early as Sunday
afternoon, and gradually spread westward across the rest of the
islands through Monday night, raising the discomfort level. This
injection of additional, deeper moisture, will result in some
spotty heavy showers especially Monday afternoon, aided by daytime
heating, light winds, and an already established unstable air
mass brought on by the upper level trough.
The GFS and ECMWF models differ with the return of the drier air
and stronger trade winds. The ec is faster with this occurring
on Tuesday. The slower GFS has the improving weather happening
Tuesday night. The past couple of GFS runs have not been all too
favorable for us to use as it take fernanda well north of the|
islands when the actual track has fernanda coming close to the
islands. But this slower drag of the tropical moisture may seem
more reasonable. This is still a couple of days down the road.
They should, and usually come to an agreement in due course.
The locally strong trade winds should start to trend down
overnight into Saturday. Airmet tango for low level turbulence is
posted over and immediately south through west of the mountains.
However, this will probably be cancelled on Saturday as those
winds return to more moderate speeds.
Clouds and showers will favor the windward and mountain areas.
Enhanced moisture tracking across the state will help fuel
scattered to likely showers along the windward areas of all
islands overnight. MVFR to isol ifr conditions in these showers
can not be ruled out. Currently, the bulk of the moisture and
clouds and showers continue to linger over the eastern islands,
where airmet sierra for mountain obscuration is posted. This
airmet will likely need to be expanded to western islands later
tonight. An mid to upper level trough digging south towards the
western island could help further enhance showers on Saturday,
possibly creating more prolonged MVFR or isol ifr conditions.
Locally strong trade winds will continue to produce small craft
advisory (sca) conditions for the typically windy waters around
maui county and the big island. The sca, currently in effect
though early Saturday morning, may be extended to noon if winds
The high surf advisory is now in effect for the east facing
shores of the big island, maui, kauai, molokai and oahu. It
remains posted through Monday morning due to a mid- to long-
period east swell associated with a fetch from when tropical
depression fernanda was a major hurricane.
The largest high tides of the month will occur each afternoon
during the next few days. Note that these high tides, combined
with wave run-up due to the east swells produced by fernanda, may
result in coastal flooding in some areas through Monday.
Elsewhere, no significant swells are expected. Small south swells
will continue to produce background surf along south facing shores
through the weekend and on into next week.
Over the offshore waters, there will be a chance of isolated
thunderstorms over portions of the area from Saturday through
Monday as an upper trough and increased moisture from fernanda
move across the area.
Hfo watches warnings advisories
High surf advisory until noon Monday for east facing shores of
kauai, oahu, maui, molokai, and the big island.
Small craft advisory until 6 am Sat for maalaea bay, pailolo
channel, alenuihaha channel, and waters south of the big island.
Weather Reporting StationsEDIT (on/off)  Help NOTE: Click on distance to see the station location on a map
|Stations||Dist||Age||Wind||Air Temp||Water Temp||Waves||Pressure||DewPt|
|ILOH1 - 1617760 - Hilo, HI||0 mi||53 min||SW 6 G 7||73°F||80°F||1016 hPa (-0.4)|
|51206||6 mi||56 min||79°F||7 ft|
|KWHH1||46 mi||53 min||WSW 5.1 G 6||80°F||82°F||1014.1 hPa (-0.8)|
Wind History for Hilo, Hilo Bay, Kuhio Bay, HI(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
|Hilo, Hilo International Airport, HI||1 mi||60 min||WSW 5||10.00 mi||Light Rain||72°F||70°F||94%||1016.2 hPa|
Wind History from HTO (wind in knots)
|1 day ago||W||SW||Calm||SW||SW||SW||SW||W||NE||NE||N||NE||NE|
|2 days ago||S||W||SW||SW||S||SW||SW||W||SW||E||E||E||E||E||SE||SE|
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
Click for Map
Sat -- 01:48 AM HST 1.52 feet High Tide
Sat -- 05:12 AM HST Moonrise
Sat -- 05:52 AM HST Sunrise
Sat -- 07:57 AM HST -0.61 feet Low Tide
Sat -- 03:07 PM HST 3.12 feet High Tide
Sat -- 06:39 PM HST Moonset
Sat -- 07:00 PM HST Sunset
Sat -- 09:41 PM HST 0.39 feet Low Tide
Sat -- 11:47 PM HST New Moon
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
Click for Map
Sat -- 03:04 AM HST 0.99 feet High Tide
Sat -- 05:14 AM HST Moonrise
Sat -- 05:55 AM HST Sunrise
Sat -- 08:38 AM HST -0.31 feet Low Tide
Sat -- 03:52 PM HST 2.78 feet High Tide
Sat -- 06:42 PM HST Moonset
Sat -- 07:04 PM HST Sunset
Sat -- 10:52 PM HST 0.02 feet Low Tide
Sat -- 11:47 PM HST New Moon
Tide / Current data from XTide NOT FOR NAVIGATION
Weather Map and Satellite Images(on/off)  Help
|Weather Map ||IR Satellite Image from GEOS|
GOES Local Image of Hawaii EDIT
Wind Forecast for (6,6,7,8)(on/off)  Help
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The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.