Wednesday, February21, 2018 L-36.com


Marine Weather and Tides
Kihei, HI

Version 3.4
What's New / NOTES
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 6:49AMSunset 6:28PM Wednesday February 21, 2018 2:45 PM HST (00:45 UTC) Moonrise 10:57AMMoonset 12:00AM Illumination 42% Phase: First Quarter Moon; Moon at 7 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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PHZ119 Maalaea Bay- 955 Am Hst Wed Feb 21 2018
Rest of today..Winds variable less than 10 knots. Wind waves 2 feet or less. Scattered showers in the afternoon.
Tonight..Winds variable less than 10 knots. Wind waves 2 feet or less. Isolated showers.
Thursday..Winds variable less than 10 knots. Wind waves 2 feet or less. Isolated showers in the morning, then scattered heavy showers and slight chance of Thunderstorms in the afternoon.
Thursday night..Winds variable less than 10 knots. Wind waves 2 feet or less. Scattered heavy showers and slight chance of Thunderstorms.
Friday..Winds variable less than 10 knots. Wind waves 2 feet or less. Scattered heavy showers.
Friday night..Winds variable less than 10 knots. Wind waves 2 feet or less. Scattered showers.
Saturday..Winds variable less than 10 knots becoming northeast 10 knots. Wind waves 2 feet or less. Scattered showers.
Sunday..Winds variable less than 10 knots becoming northeast 10 knots. Wind waves 2 feet or less. Scattered showers.
PHZ100 955 Am Hst Wed Feb 21 2018
Synopsis for hawaiian coastal waters.. High pressure far northeast of the area and a surface trough northwest of kauai will support increasing east-southeast winds over the coastal waters from Thursday through next week. An upper level disturbance will bring heavy showers and a slight chance of a Thunderstorms, spreading from south to north between tonight and Friday night.

7 Day Forecast for Marine Location Near Kihei, HI
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location: 20.75, -156.45     debug


Area Discussion for -
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Fxhw60 phfo 212010
afdhfo
area forecast discussion
national weather service honolulu hi
1010 am hst Wed feb 21 2018

Synopsis
A relative dry day is expected today, but expect a wet end to the
week and into the weekend. The big island could see some showers
developing this afternoon, with wet weather increasing tonight,
and persisting through the end of the week. The rain will likely
spread over the smaller islands tomorrow. A nearby upper level
disturbance will bring the chance for heavy showers and
thunderstorms through the weekend.

Discussion
No change to the forecast this morning, aside from some minor
tweaks to a few grids to ensure consistency between fields. Will
likely be making more tweaks throughout the day to refine various
parts of the forecast, but not expecting any major changes to the
forecast philosophy.

A flash flood watch is set to begin tonight for the big island,
and we are anticipating expanding that to the smaller islands
tomorrow. That expansion will likely be issued later today. A high
wind warning remains posted for the big island summits, although
wind speeds are on the decline. Will likely be canceling the
warning and posting an advisory that will persist through the
night. The winter weather watch posted for the big island summits,
will likely become an advisory with the afternoon package.

Although the chances of winter weather are minimal tonight, the
possibility is there, and the chances increase tomorrow onwards.

The overnight surface analysis had a weakening trough over the big
island, and to the northwest of kauai. A look at water vapor
imagery shows the upper level trough that will play a big role in
our weather over the coming days is about 900 miles west of kauai
this morning. The upper trough is expected to deeper and move
closer to the islands over the next 24 hours. The GFS forms an
upper level low along this trough axis by Thursday afternoon,
about 700 miles northwest of kauai. The trough then deepens, and
remains nearly stationary along 170w through Saturday morning, and
then begins to lift northward.

Overnight sounding from lihue had precipitable water (pw) values
around 1 inch which is normal for february. At hilo, the pw was
1.5 inches which is above normal. A check of satellite derived pw
shows a large area of pw above 1.5 inches, over and south of the
big island. The GFS shows this 1.5+ inch area spreading to the
smaller islands by tomorrow and persisting into the weekend.

Meanwhile, colder upper level temperatures are moving in from the
north. Overnight both soundings had 500 mb temperatures around -10
c, which is near normal for february. Colder than normal 500 mb
temperatures are expected to move over kauai by tomorrow morning,
and spread over the smaller islands through the day with the
coldest temperatures remaining over kauai. This cold air persists
into the weekend. The GFS currently keeps the 500 mb temperatures
over the big island near normal. A number of factors are a concern
with this upcoming event. Near the big island, the pool of above
normal pw combined with near normal, upper level temperatures can
still produce thunderstorms. Near kauai, the colder upper level
temperatures can help to make up for the pw not being quite as
high. There will be enough shear in the environment to support
some thunderstorms having gusty winds, but the placement of all
pieces is still to be determined.

Although we are expecting rainfall to increase across all
islands, the biggest threat initially will be over the big
island. As the ingredients spread to the smaller islands, kauai
will be a big concern with their proximity to the upper level
disturbance. Recent rains over oahu, maui county and the big
island will play a larger factor for flooding threats in those
areas.

The other concern not yet mentioned is the southeast flow that is
expected. This pattern can bring additional rains to the eastern
side of oahu, and area that was hit particularly hard during the
rain event last weekend. The direction of the wind flow and the
length of time that flow sets up will play a large part in any
training of showers over that area starting Thursday.

As we head into the new work week, surface troughs linger to the
west of the islands, with a surface high far northeast of the
islands. This would maintain a southeasterly flow over the islands
which could keep showers around. The main difference is the upper
levels where things at least start to stabilize.

Aviation
Vfr from kauai to maui and anticipated scattered MVFR conditions
on the big island. Moisture is already moving in SW of the big
island so heavier rain is possible with daytime heating. An
airmet for mtn obsc might be necessary later today for the big
island. Moisture moving in from the S may bring showers from maui
to oahu toward the end of the period.

Marine
The arriving wnw swell looks to be peaking at buoy 51101, a
couple hundred miles NW of kauai. The swell should then hold near
this level into Thursday. This should translate to advisory level
surf reaching kauai and niihau later this morning. A high surf
advisory is posted for the exposed N and W facing shores of kauai
and niihau. The swell, however, is not expected to carry enough
energy to produce advisory conditions for the other islands. After
this swell fades Friday into the weekend, long term guidance does
not favor another wnw NW swell at least through next week mid
week.

Persistent high pressure NE of the state will continue to produce
an area of strong winds directed towards the area. We should
start to see an uptick in ese SE winds around the state starting
Thursday, and remain elevated at least through midweek next week.

The swell generated from the broad area of strong winds will
produce elevated surf along E facing shores. A high surf advisory
likely be needed by Thursday night or Friday could potentially
reach warning levels by midweek next week. The combination of the
elevated seas and increased winds, starting tomorrow, will
produce small craft advisory conditions, mainly for the channels
and exposed windward waters.

Small long period S swells could produce a small bump in surf
along the S facing shore this weekend.

See the latest oahu surf discussion (srdhfo) for additional
details on surf and swell.

Hfo watches warnings advisories
High surf advisory until 6 pm hst this evening for niihau-kauai
windward-kauai leeward.

Flash flood watch from 6 pm hst this evening through Friday
afternoon for kona-south big island-big island north and east-
kohala-big island interior.

High wind warning until 6 pm hst this evening for big island
summits.

Winter storm watch from 6 pm hst this evening through Friday
afternoon for big island summits.

Discussion... M ballard
aviation... Chevalier
marine... Eaton


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
KLIH1 - 1615680 - Kahului Bay, Maui, HI 10 mi45 min NE 9.9 G 14 78°F 78°F1014.1 hPa (-2.0)
51205 19 mi45 min 76°F7 ft
51202 - Mokapu Point, HI (098) 80 mi41 min 75°F6 ft

Wind History for Kahului, Kahului Harbor, HI
(wind in knots)    EDIT      (on/off)   Help
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Kahului, Kahului Airport, HI10 mi51 minNE 1110.00 miMostly Cloudy83°F70°F65%1014.8 hPa
Lahaina - West Maui, HI21 mi55 minSW 415.00 miOvercast79°F71°F79%1015.2 hPa

Wind History from HOG (wind in knots)
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Last 24hrN9N8N7N6N6N4E4E5CalmCalmS3SE5SE3CalmSE3N6NE3CalmW3CalmCalmN6
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1 day agoN9N9N8N6N5E5CalmCalmCalmCalmSE5SE5SE6SE3SE6S3SE6SE4N3N7N6N10NE10N10
2 days agoNE19
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N9NE10NE9E6E6N3N5NE7N8N8N9N11

Tide / Current Tables for Kihei, Maui (Hawaii)
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Kihei
Click for Map
Wed -- 02:00 AM HST     0.54 feet Low Tide
Wed -- 06:51 AM HST     Sunrise
Wed -- 07:45 AM HST     1.35 feet High Tide
Wed -- 10:56 AM HST     Moonrise
Wed -- 02:08 PM HST     0.02 feet Low Tide
Wed -- 06:27 PM HST     Sunset
Wed -- 09:30 PM HST     1.76 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.90.60.50.60.811.21.31.31.31.10.80.40.100.10.30.711.31.61.71.71.6

Tide / Current Tables for Kahului, Kahului Harbor, Hawaii
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Kahului
Click for Map
Wed -- 05:14 AM HST     1.72 feet High Tide
Wed -- 06:51 AM HST     Sunrise
Wed -- 10:56 AM HST     Moonrise
Wed -- 12:11 PM HST     0.18 feet Low Tide
Wed -- 06:27 PM HST     Sunset
Wed -- 07:13 PM HST     1.50 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.80.91.11.41.61.71.71.51.20.80.50.30.20.20.40.711.21.41.51.51.41.21.1

Weather Map and Satellite Images
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Weather Map
wmap_P
IR Satellite Image from GEOS
cpac_satellite

GOES Local Image of Hawaii    EDIT
Geos

Wind Forecast for (19,4,5,8)
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Ground Weather Radar Station Kohala, HI
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weather_mapweather_map weather_map

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Disclaimer:
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.