THE LATEST IN DEPTH VIDEO PRESENTATION OF HAWAII'S WAVES,WINDS & WEATHER FROM SURF NEWS NETWORK & SPONSORED BY HAWAIIAN SOUTH SHORE

Winds Statewide in a glance ...just go HERE (this link is also the 4th drop down under weather)

May 21, 2013 4:00 AM HST

Synopsis
A land and sea breeze weather pattern will persist over the islands through Wednesday as an area of low pressure stays several hundred miles north of the state. Lingering moisture associated with the low pressure will bring slightly higher chances of rain to the eastern portion of the state today. Trade winds will rebuild over the islands by Thursday as the area of low pressure drifts away and dissipates while a surface high pressure moves to far northeast of the state.

Discussion
An area of surface low pressure persists in the island vicinity this morning, keep winds light over the islands. Land breezes have developed overnight resulting in a decrease in showers over the islands. Moisture from a dissipating front as well as low level convergence bands lingers over the eastern portion of the main Hawaiian islands. The moisture, coupled a slightly unstable air mass, as depicted by early morning Hilo sounding, has allowed some deeper convection to develop in the Maui county and Big Island vicinity since last night. There is also a batch of low clouds affecting Kauai, though early morning Lihue sounding indicates the air mass is more stable and drier compared to Hilo's. Strong winds associated with the upper level low pressure system continue to affect the summits of the Big Island early this morning. The winds will probably last through this evening, therefore a wind advisory remains in effect for that area. Expect a repeat of yesterday weather over the islands today as the state's weather is still pretty much under the influence of the nearby low pressure, with highest threat of rain as well as possibly locally heavy showers over the eastern islands. The rest of the islands may see a chance of rain, especially during the afternoon and evening with the convective clouds under day time heating.

The area of surface low pressure will slowly weaken and drift away from the islands in the next couple of days, as the associated upper level cut-off low lifts north. Winds will remain light enough over the islands Wednesday such that the present convective weather scenario will continue. Lingering moisture associated with low level convergence and the old frontal boundary is also expected to hover nearly the eastern islands while slowly dissipate. Therefore, a slightly higher chance of rain is expected over Maui county and the Big Island Wednesday forecast charts indicate a surface high pressure will move to far northeast of the state by Thursday. As the surface low pressure system drifts away and dissipates, trade winds will slowly rebuild over the islands. Trade wind weather will return to the state by then as well. Moreover, the surface pressure gradient across the islands is expected to tighten by the weekend. Trade winds will strengthen and become locally breezy. Passing low clouds and showers will affect mainly windward and mauka areas, and may even reach the lee areas of the smaller islands at times. Forecast charts do hint the development of a weak upper feature near the western islands. This feature may enhance the trade showers at times.

Marine
The high surf advisory for south facing shores continues through this evening as a large south swell persists. Elevated surf for south facing shores will last at least through Wednesday. An out of season, moderate, west-northwest swell is expected to arrive tonight and peak Wednesday into Thursday, bringing near advisory level surf for north and west facing shores.

Trade winds are expected to be strong enough by the weekend for small craft wind conditions to develop over the windier Maui county and Big Island coastal waters.

Watches/Warnings/Advisories
High surf advisory until 600 pm HST this evening for south shores of all islands.

Wind advisory in effect for Big Island summits until 6 pm HST this evening.

BIG SURF PICTURE Wednesday 5/13/13 

NPAC  Looking above average from Saturday through next Saturday.

Currently: lingering N swell at up to 0-2' for Laniakea and 1.5' for other spots.

Next: A marginal gale floats east off the Kurils all week crossing the dateline Wednesday up above 40 degrees north or about 1000 miles away. We can expect a fun spring time 11 second, 2-3+ NW filling Saturday and holding 3' Sunday before fading next week.

Last: Models keep supporting a unseasonal Low off Japan tonight which will stall then track ENE about 2000 miles away; she fades near the dateline Sunday but not before pushing out some 14 second NW swell with easy 4-6' surf Wednesday. We may give it an upgrade as buoy forecast currently show 6' 15 seconds which is enough for "almost" 8' at focal reefs like Sunset.

Long range fantasys need focus.

(See HERE)

SPAC  It has been a really good spring with half a dozen swells aready but now it's really 'up there' in the ratings.

Currently: its cranking 4-6 from the S to SSW with higher sets and buoys 5' 17 seconds. So some reefs hit 8' today.

Buoys popped Wednesday nite at  20 sec forerunners from a rare run of SSW to S swell. Ascat wind measurements confirm a big storm with a good ''following fetch' on its NE track up and then out from the east coast of NZL this past Thursday-Saturday. Seas are about 35-40' and winds were solid 45kts over a wide area. We'll see our 1st of 4 advisory SSW swells filling late Thursday to solid 4' and even 6' at 'select reefs; a peak of 5' open ocean 16-18 second event (country hits 8' with this kind of reading). Our guesstimate peak on Friday afternoon is 4-7' surf (2.5 times overhead) into Saturday and even Sunday since the system stalled.

Next: This giant storm stalls or occludes over the weekend of the 18th more to our South allowing for another shot of lasting South swell in the 3-6' range but with 15 seconds.

Next: Another Low has its fetch off to the SE of NZL Monday-Tuesday 5/14 pushing up some solid 3-5+' South by Monday-Tuesday 5/20-21. She'll be a notch smaller than the 1st pulses.

Next: The final shot from this 4 swell series is filling late Tuesday peaking Wednesday at 3-5' then down 2-4' Thursday....

Last: we go into a relatively quite period till further notice. But models have a more background 1-3' South surf  with 15 seconds (2' open ocean) from Friday afternoon into Monday; this is from more distant zonal storms.

East Shores: Strong 1028 mb High to out NE fixes out weather and waves. Up to 3' is the trend from the fresh NE winds and N swell.

Tropics: This past Thursday model have a storm moving west under Baja . She dies off this Sunday as soon as she hits cooler water.

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.