BIG PICTURE: Sunday 3/18/18
NPAC: The large upper airflow 30,000+ feet up in the atmosphere off Japan was low, consolidated earlier last work week with some 130-170kts and reaching past the 180 dateline. But this weekend it weakens which hurts its cause in the formation of surface Lows. There is not much to steer toward Hawaii. Plus, most storms bump into the never-ending strong High to our NNW and splits the Jet flow into 2 branches.
Recent-Current: A small-moderate 2-4’ NNW made it to our NW shores earlier than expected Saturday the 17th. This one fades into Sunday to head high maybe 1’ over max. The source was a Low on the dateline Tuesday-Wednesday which hovered then fast-tracked NE Thursday. Thus, a short-lived smaller event than we hoped.
Next: A strong but distant east tracking storm off Kamchatka has 20-30’ seas stay far away. Models suggest some 2’ swell @ 15sec NW reaching 2-3’ surf Monday the 19th. It’ll be 2-3’ max Tuesday early as it fades.
Next: This Monday the 19th there’s a gale spinning 1200 miles NNE; it occludes and strengthens to strong 45kts into Tuesday-Wednesday and should bring in longer lasting advisory size 5-8’ NNE surf at 15 sec. filling noonish Wednesday to solid 5-8’ and lasting into Thursday the 22nd. It will then drop about 25% Friday and every day after.
Last 2: A weak eastbound Low off the Kuril Islands forms Sat the 24th. This won’t do much more than 2’ surf for us at 12seconds Tuesday afternoon the 27th into Wednesday. Even this is sketchy.
The GFS (global forecast system) which goes out 16 days hints of a Low sitting our side of the dateline about 1500 miles NW on Wednesday the 28th. Just a heads up for a low possibility NW Friday into Saturday.
The Jet is in disarray by this weekend. It’s all high pressure to the east of New Z and this is our best zone for SSW swell. Though’ one Taz Low was spawned from the energetic jet today. The Jet has been overall weak with one good trough that started deep under the Taz over 10 days ago and pointed up the east coast. But no real decent Lows spawn for overhead.
This Friday the 23rd the Jet is veering ENE far SE of New Z as it tracks further east. Some Low pressure is spawned but nothing to write home about as most the energy passes to our SSE.
Lastly, Sunday the 25th the Taz gets some Jetstream support for another Taz event about 7 days out or early April.
Recent/current: We’ve had SSW waves signaling Spring with some 3’ solid last Wed 3/14 from a couple sources SW to SE of New Z…a trace of 14 sec waist to chest high SSE swell from a system far SSE of French Polynesia a couple Tuesdays ago. Since then it’s been on the downtrend.
Next: Friday the 16th showed a long wide fetch to the east of New Z but from the Samoa readings, it’s not looking as promising as we hoped. Maybe some chest high at 16 sec filling in Friday the 23rd peaking same Saturday-Sunday 24-25th with more consistency. Sunday may see some 3’ sets.
Last2: Monday the 19th we see a Taz Low far south with an east track limiting the time for sea development. The winds were 45-55kts tho’ so the periods will be long 16-18sec forerunners around Tuesday the 27-28th. The swells will only be 1’ however so don’t expect for than the occas. chest-shoulder high wave or 2.5’ local size.
There’s another Low under Tahiti at 40south so just 3600 miles SSE. Models hint of some 1’ 14 sec SSE around Thursday-Friday the 29-30th. It’s low confidence.
Currently: Surf’s been going off all Month until this weekend. Wednesday it was down 2-4’ occ 5’ from the N in addition to the strong gusty NE trade swell. We faded since and were back to normal 3’ ENE windswell today Saturday. NE Trades fill Sunday and should revamp the choppy surf to almost 3’ at 8 sec by Monday.
Then the windward side gets some serious support once again from a 3-6’ NNE Wednesday-Friday. Some NE exposures will reach 8’ easy. Double the 4+’ threshold (8’ faces) for high surf along the east shores of the Islands.
Surf backs down to safer levels over the 24-25th weekend.
Tropics: nothing for the next couple days.
NWS criteria for High Surf Advisories (first number) & Warnings (second number).
All surf height observations & forecasts are for full ‘face’ surf height, or ‘trough to the crest’ of the wave.
Advisory and Warning Criteria Shoreline or Location
North-Facing Shores 15 Feet and 25 Feet
West-Facing Shores – Remaining Islands 12 Feet and 20 Feet
West-Facing Shores – Big Island 8 Feet and 12 Feet
South-Facing Shores 8 Feet and 15 Feet
East-Facing Shores 8 Feet and 15 Feet
Links: Get the latest Central Pac Hawaii go HERE
Terms: split Jetstream
Notes: Spectral density graph in the SNN Buoy Page GO HERE shows slivers of forerunners that initial text readings of new swells which often do not ‘show’ till later on written/text buoy updates. Also, note the vertical graph is not ‘wave height’ rather its a measure of wave energy in hertz (frequency or cycles/sec) for the whole ‘band’ (the distribution of power/period in the total wave energy field/spectrum). For the SNN Buoys ‘per shore’ arrangement GO HERE