Waves, Winds, Weather compliments of Leahi Health Beverages
Your exclusive SNN Obs for this Thursday Aug. 28th 3pm special update
High Surf Advsry's posted for all S and E shores in advance of a big surf.
50% sun/clouds with ENE trades 10-20 winning out over seabreezes. Had the 1.5' High tide @ 6am dropped out to a .4' Low tide @ 1130am pushing up the rest of the day to 1.6' at 530pm.
Kaisers, Kewalos (check our Bowls-Courts CAM); super clean ENE offshores;. Diamond Head: Up and rising on the new SSW at 2-3' mostly (chest) solid 4' surf with nice lines and so far it's good sideoffshore ENE trades at 10-20 (see SNN Cam). Sandy's: Up and rising esp later on the SSW and E wrap at a good clean 2-3+' and plenty barrels and breaking all over. East: Makapu'u: Up a notch and rising all day from the EAst swell the slightly bumpy 2-4' and bigger soon on on the longer period 15 second East (Hurrincane Marie). Waves outside now on the left to Ala Moana,
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THE WHERE, WHEN & WHY OF HAWAII’S WAVES & WEATHER: A VIDEO PRESENTATION BY SNN
Winds Statewide in a glance ...go HERE (this link is also the 4th drop down under weather)
Aug 28, 2014 4:00 AM HST
Trade winds will slowly weaken today and remain light through the weekend, allowing afternoon sea breezes and nighttime land breezes to develop over leeward areas. Afternoon and evening clouds and showers will develop over leeward and interior areas, followed by nighttime clearing, while passing low clouds may affect the windward areas at times. Stronger trade winds may return next week.
Trade winds continue over the islands early this morning as indicated by surface observations around the state as well as wind profiles from radar data. Radar and satellite data indicate there are some low clouds and showers in the island vicinity this morning, and some of these clouds are reaching the islands, bringing some showers to mainly windward and mountain areas. Early morning soundings from Lihue and Hilo continue to show a marginally stable air mass in the area. Trade winds are expected to hold over the island today, as a surface high pressure remains far north of the state. Passing low clouds and showers will affect mainly windward and mountain areas.
Winds are expected to slowly ease over the next few days as a low pressure system from the east Pacific passes north of the state. Winds will become light enough over the islands tonight to allow land breezes to develop. As such, the diverging land breezes will bring some clearing skies to the state overnight, though low clouds embedded in the light trade wind flow may still affect the windward areas at times. A more convective weather pattern is expected over the islands Friday and Saturday, with clouds and showers developing over the islands in the afternoon and early evening hours under the converging sea breezes, while some clearing may occur at night under the land breezes. Air mass is forecast to remain somewhat stable in the island vicinity as there will be upper level ridging. On the other hand, moisture associated with the passing low pressure system north of the state may bring more clouds and even showers to Maui county Friday night, reaching Oahu on Saturday, and spreading to Kauai late Saturday into Sunday.
The light trade wind scenario will last into early next week.as such, the islands may experience hybrid convective and trade wind weather for the rest of the holiday weekend, with low clouds and showers affecting windward areas at times, while the lee areas may see afternoon and evening clouds and some showers. Stronger trade winds may still return to the islands by the middle of next week, though the wind speeds will stay modest at best. If so, more typical trade wind weather will return to the islands as well.
Latest data from the near shore buoys just east of Oahu and north of Maui still showed no sign of the anticipated abnormally long-period swell from hurricane Marie early this morning. Still expect this swell to slowly reach the island waters later today, and will bring advisory level surf to east facing shores today through Friday. While surf heights are not expected to be exceptionally high, long period swell energy from the east is somewhat unusual, resulting in normally sheltered windward locales seeing larger long period waves and strong currents.
Latest readings from the near shore buoy just southwest Oahu indicated the south swell has arrived, though swell heights are a tad lower than expected at this time. Still believe this south swell will continue to build today, bringing advisory level surf along south facing shores through Friday. Strong currents will develop in some areas due the interaction between these two swells. The surf from both swells will slowly decline over the weekend.
As winds slowly diminish, no small craft wind conditions are expected through the holiday weekend. However, the long period easterly and southerly swell mentioned above could bring confused seas to areas exposed to both swells.
High surf advisory from 6 am today to 6 am HST Saturday for Niihau, Kauai windward, Kauai leeward, Oahu south shore, Waianae coast, Oahu Koolau, olomana, Molokai, Lanai makai, Kahoolawe, Maui windward west, Maui leeward west, Maui central valley, windward Haleakala, leeward Haleakala, Kona, south Big Island, Big Island north and east.
BIG SURF PICTURE 8/26/14
The Jet down under has been dominant with equatorial bound (ENE) flows leading to plenty surf, but the last few days its been zonal (west to east) with 2 branches staying the same most this week. By Thursday/Friday there’s another ENE tilt which will enhance a big storm but it'll be sending much of the energy off to our east since the equatorbound flow is far off NZL to under French Polynesia.
Recent: We’ve had nonstop surf for about 2 weeks; 2 Lows tracked SE of NZL Thursday 8/7 and these sources created surf the 1st weekend for the Dukes Oceanfest! Then a powerful Low a few days after with 55kts saw into our window SE of NZL hugging the East coast with a captured fetch. We got 18 sec forerunners Wed the 20th reaching 3’ 15 sec swells or 2-4+ SSW surf Thursday midday and the final Dukes weekend…one of the best weeks for the OceanFest in over 5 years.
Currently, we saw some 4’ sets from the SSW this past F-M from 2 sources: a gale 40kt storm east of NZL mid August. Her fetch head got to 3500 miles away which allowed for head high sets. Then a stronger system further SE of NZL with 47kts added more size over the weekend and into Monday. Some spots peaked 5’ over the weekend but these were special cases/spots. Things level off to head high Tuesday.
Next: Another compact Low SE of NZL tracked east again last Monday-Tuesday and will keep us at 3’ solid before a SSW swell arrives Wednesday.
Next: The Jet set up a long wave trough from Wednesday the 20th. We also saw a big High in the Taz which created solid winds in between the High spinning counter clockwise next to the Low spinning clockwise (opposite spins from the NPAC). This allowed a huge fetch area east of NZL last Thursday-Saturday. The head of the fetch got to within 3000 miles which is about 1000 miles closer than the usual. This means less ocean swell decay over distance and another round of advsry surf filling late Wednesday peaking Thursday into Saturday and even Sunday…High Surf threshold for South swell is 8’ crest to trough which is what typical surfers look for. The NS needs 15’ or twice the size which most surfers don’t look for. Why the large difference is likely extra safety precautions where populations are greatest.
Next: : Models backed down big time on their output a week ago for a new event early Sept. A broad gale Low far east of NZL reached near Tahiti last weekend. Now, it’s going to be 1-3’ South Sunday-Tuesday.
Last couple: Low confidence of models showing a big broad storm up off the Ross Ice Shelf Wed the 27th which fades fast and followed up fast by a much bigger Low Thursday. The issue is the ENE track but side band swell should hit 3 maybe 4’ with long periods Thursday sept 4-6th. Let’s take a better look this weekend.
The weak Jet up North is continuing it’s summer position with poor potential for swell enhancement, and tho’ she’s elongated the winds are too light for anything. Most the deeper troughing occurs under the gulf toward the end of the 7 day forecast.
Recent: It’s been quite and average after the long run of Typhoon West swells and Hurricane N swells making Aug the best in memory. Reliable sources like Pat Kelly with over 40 years up there plus, a former NS Capt and SNN eye’s on the country claimed it.
Next: East wrap from hurricane Maria will send long 2-3’ 14-16 second periods producing surf up 4’ around Kahuku and less to select spots toward Haleiwa starting Thursday and into the weekend.
Next: nothing is on the models out over 10 days.
Recently, small 2’ East swell have been dominant but that’s increasing today from 2 Tropical systems: Lowell and Karina off Baja and weakening. Then it goes up big time with a rare push of 14- 17 second East surf from Cat 5 Hurricane Maria tracking ENE off of Baja (see below). Surf on the windward spots will reach as high as 7’ local scale. We also have two 1030mb High up beyond 40 north or 1200-1500 miles away keeping us in the typical trade wind pattern. So after this upcoming run its back to normal by next Wednesday.
Tropics: Cat 5 Hurricane Maria built this past weekend SSW of Baja and is expected to move NW and weaken to a Tropical Storm before Friday staying over 1200 miles to our NE. She built 40’ seas and will send off some of that High surf advsry East swell Thursday-Saturday. The main feature will be the long periods which refract and shoal off the ocean floor much more than the typical 8-10 sec windswell we usually ride. Watch for spots to break with more power and current.
FETCH: Often called the fetch length, is a term for the length of water or distance over which a given wind direction has blown. Fetch length along with the wind speed (or strength) determines the size of waves produced. The longer the fetch length and the faster the wind speed, the larger and stronger the wave will be and vice versa.
CAPTURED or FOLLOWING FETCH: Not only does the fetch length determine the power and energy of the wave. Additionally, if the winds/fetch are blowing in the same direction as during the wave's or storm's lifetime, the wave will in turn be even stronger. The fetch is related to the orbit of the wave and track of the storm.The longer the wind drags along the sea the more energy the wave will have. This can be seen not just in vertical height measurement but in wave period (the measurement of waves through time).
WAVES PERIOD:Time, in seconds, between the passage of consecutive wave crests past a fixed point. In general the longer the period the bigger the wave. Windswell or 'close interval' swells are under 10 seconds. Big 'ground swells' are 17-20+ seconds (note: a 20+ second swell needs storm force 50+kt winds blowing over a 1500 mile fetch to be fully developed' into 20-25' beasts; these 20 second waves can be felt 1000 feet down!). This is why they jack so much more, pulling large amounts of H2O off the outer reefs.
More generic marine definitions click this link http://www.prh.noaa.gov/hnl/pages/marinedef.php
....All surf height observations and forecasts are for the full face surf height, from the trough to the crest of the wave.
|North-Facing Shores||15 Feet (8')||25 Feet|
|West-Facing Shores - Big Island||8 Feet (4'+)||12 Feet|
|West-Facing Shores - Remaining Islands||12 Feet (7')||20 Feet|
|South-Facing Shores||8 Feet (4'+)||15 Feet|
|East-Facing Shores||8 Feet (4'+)||15 Feet|