Waves, Winds, Weather compliments of The Shorebird Restaurant
Your exclusive Observations for Thursday April 17th at 630am update
Decent weather today with continuing moderate to fresh E-NE trades later this morning. Tide is dropping out first half of the day to a -0.2 Low tide at 11am then pushing up the rest of the day to a 2' High at 6pm
SMALL CRAFT ADVISORIES & HIGH SURF ADVISORY FOR EAST FACING SHORES
Quote of the Week "I need to feel it as an education to put myself in the zone" Pete Mel on Mavericks Invitational 2014.
THE WHERE, WHEN & WHY OF HAWAII’S WAVES & WEATHER: A VIDEO PRESENTATION BY SNN
Winds Statewide in a glance ...just go HERE(this link is also the 4th drop down under weather)
Apr 16, 2014 4:00 AM HST
Moderate trade winds will continue through the weekend and into next week, possibly peaking in strength around Sunday night. Active showers moving in on the trades will diminish today, and then increase from Thursday into Friday, but then eventually become limited mainly to windward slopes.
Surface observations around the main Hawaiian islands still reported moderate to locally strong trade winds blowing. Precipitable water in the air mass was near typical values around the state, and slightly higher upwind, though drier air prevailed in most other directions.
Through most of the night, a weakening mid-level trough to the northeast through east provided uplift, raising the inversion height and encouraging showers passing under it to develop more than usual. These showers then trained over the islands from the east. However, as the trough weakened gradually, this stream of showers diminished with time. Rain rates approached moderate strength in some areas, but accumulation overall remained on the light side.
Guidance generally agreed that through the short run, moderate to strong, if flat, ridging aloft extending over the islands from the northwest will expand further toward the east, while the trough will continue to recede toward the northeast. The resulting deep ridging then will persist through the rest of the forecast period, displacing the storm track too far north to have much influence on the state.
Under these conditions, the subtropical ridge at the surface will receive enough support from aloft to keep trade winds blowing through the weekend and into next week. Solutions did differ somewhat with respect to wind speeds over time, but the consensus kept speeds near moderate levels throughout, with a possible peak near Sunday night.
Deep ridging also will tend to lower the inversion height over time, and guidance predicted the air mass to dry a bit, so shower activity will diminish. However, solutions supported a plume of more humid air to train over Maui and Hawaii counties from Thursday through Friday. Thus, pops and related fields have been increased slightly through this time. Also, orographic forcing will continue to squeeze out some moisture along windward slopes, so the greatest drying will occur mainly leeward.
The small craft advisory /sca/ was extended through this afternoon for the channels and waters around Kauai and Oahu, and continued through Friday for typically windier areas around Maui and the Big Island. Trade winds will diminish somewhat today, but then remain moderate to fresh through Friday. Wind waves produced by the persistent trade winds also will continue to require a high surf advisory for east-facing shores through this afternoon.
A small swell from the west northwest will arrive late today, and then peak Thursday below the advisory levels. No other significant swells are expected.
High surf advisory until 6 pm HST this evening for Kauai windward, Oahu Koolau, olomana, Molokai windward, Maui windward west, windward Haleakala, south Big Island, Big Island north and east.
Small craft advisory until 6 pm HST Friday for Maalaea Bay, Pailolo channel, Alenuihaha channel, Big Island leeward waters, Big Island southeast waters.
Small craft advisory until 6 pm HST this evening for Kauai northwest waters, Kauai windward waters, Kauai channel, Oahu windward waters, Kaiwi Channel, Maui county windward waters, Big Island windward waters.
BIG SURF PICTURE 4/12/14 Saturday update
The Jet has a 150mph trough inbetween Japan and HI at 30-40N latitude or 600-1200 miles north of us. There's lotsa of broad weak Jet winds from the dateline to over Hawaii thus the wetter weather. A strong High bounces the Jet up and over HI Sunday into next week. Also a new trough moves our way of Japan again Monday allowing for slight potential for continued storm development. By Friday the 18th its very weak tho' extended across the NPAC to the west coast. Hinting of a long term quite period.
Currently, we have a nice sized high surf advsry level 15 second NW reaching heights of solid 8' or triple overhead for Pipe and Sunset. Winds are NE sideshore but hey its got power. The source of Saturday's peaking event was a broad gale near the Kurils last Sunday moving east making for 28' seas. This swell will drop a lot to about 3-4' maybe 5' Sunday morning.
Next: A Low pops on the charts Friday 4/11 near the Kurils Is again but this ones smaller and farther away (2200 miles). Winds are stronger but wont make up for the afore mentioned factors. She'll build Wed nite the 16th peaking 5-7' Thursday from the WNW.
Last: The Jet goes zonal mid April with quick eastbound Lows bring short lived smaller spring like/small NNW surf next Saturday. Keep you posted. Better shot of NW possible on Thursday the 24th.
Long range models love to fantasize. Meaning they run 'hot' making promises they can't always keep.
SPAC: The Jet is weak and zonal or west to east from Sat to Wed. the 16th when a weak NE flow shows esp by Friday-Sunday. The main push for swell will move out of our window.
Currently: Distant past sources make for background 14 seconds with just 1' swell...this leads to 2' surf for most spots thru next weekend. Below average.
Next: If long range outlook stands the test of time we'll get a 2' SSW Thursday the 24th from a marginal NE bound Low Thursday the 17th.
Last: Friday the 18th shows a large Low far south of Tahiti ramping to 35' seas by Saturday as it tracks ENE out of our window; maybe some long period 2-3' sideband SSE surf Saturday the 26th.
The Windward side see’s small 2' ENE wind swell at 8 seconds ramping to 2-4' this weekend esp Sunday into Monday the 14th from increasing trades from the building strong High. Chance of high surf advsy surf. Model hint of Trade fetch weakening Tuesday thus a weakeing windwave swell esp by Wednesday. Typical spring.
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|