Big Picture

SNN BIG PICTURE: Saturday Am 9.15.18

2.5 more months of Hurricane Season. So far, above-average season in 2018, with a total of 17 named storms, 7 hurricanes, and 3 major hurricanes. Lane was the first Cat5, though Hector was the first to cross all 3 basins…the east, central then west pacific. BTW, Lane was Hawaii’s wettest Hurricane EVER…

NPAC:  Same story: The upper atmosphere’s energy known as the Jetstream, is very weak and split from 160-140E Lat (Our N to ENE) with High pressure dominating the East basin. Jet level winds say less than 100kts into next week with breaks abounding & High’s dominating. Not good. Middle St merge week see’s small 140kt pockets but they flow the wrong direction thus no ground swell. A cut off spinning Jet midweek the 19-21st has no energy transferred to the surface yet. By next weekend the 22nd there’s more energy overall.

Recent-Current:  Finally saw a small NW swell hit easy 3’ even a few overhead sets Thursday as forecasted and faded from Friday into the weekend. It’s been endless NE swell the last couple few weeks of which many were Hurricane related: Norman and then Olivia.  The NW source was from the cut off Jet mentioned above leading to a cut off surface Low near the dateline 1200 miles away earlier this past week. The gales pushed 18’ seas for some 3’ swell at 12 sec, thus 2-3’ average sets from the NW midday Thursday. Most of this fetch pointed SW of us.

Next: On Thursday there’s another small weak gale Low tracking SE off the Kurils & its nose reaches the dateline 1200 miles away. A second, slightly smaller 1-2-3’ NW fills in Sunday late afternoon peaking Monday the 17th then fading into Tuesday.

The surf production line then shuts down for 7 days after the tiny NW event Monday. So expect 0-1’ from Thursday the 20th into the final week of Sept.

Last: The GFS (global forecast system) is jumping around on the long range but we’ll go ahead with a ‘heads way up’… Our first real ‘wintery’ NNW could hit 10’ Saturday the 29th. A nearby Low centered 900 NNW of us Tuesday the 25th is the culprit. But such systems are fickle. It’s a long way out so lets go with less than 50/50.


The Jetstream improves its southern branch to 160kts this weekend. The northern branch has it’s 180kt pockets under and south east of Tahiti.  A Big High Pressure sits right over NZL recently and moves east thru the week getting stationary in the central basin.

For over 6 weeks, the Highs have dominated most the usual SSW swell generation zone off the East Coast of New Z. This poor set up finally changed as a meridional NNE flow showed up NZL east coast this past weekend and Monday the 10th. A surface Low is steered by the Jet up towards Hawaii with a long lasting ‘following’ or captured fetch.  After this swell production, the machine shuts off with no proper flow out 7-10 days.

Recent/current: Today it’s a declining small South at up to chest high. Some fun 1-3’ SSW got here at 14-16 seconds last work week. A small but 50kt Low to the NE of NZL got its fetch going last Friday- Saturday to push up some mostly small 3’ or chest-head high SSW Thursday and its veered South. It got here sooner since the fetch was 600-900 miles closer than the usual zone 4000 miles away.

Next: A better shot of SSW is possible Tuesday the 18th. Last Tuesday 11th a low tracked East out from under the SE of NZL and veered NNE Wed-Thursday with a captured fetch. This allows the seas fuller potential out of the storm. The fetch was weaker than the prior but is much longer… and longer lasting. In fact, the storm veered East into Thursday the 13th far to the ENE of NZL as it looks to merge with a Low under Tahiti. The Low is weak and nearly out of our window by Friday the 14th. We can hope for a long lasting 2-3’ SSW surf at 16 sec Wednesday the 19th thru Saturday when the direction will be more South.

Last: Storms are mostly zonal or west to east after this thru Wednesday the 19th. We see only background .5’ to 1’ swells up to 16 sec from the SW to SSW…

Windward Shores:  It’s been upstream Trades pushing up some marginally High ENE surf. After the 10’ peak of Olivia Wednesday It went Way down Thursday to 2-4’ … It’s reinforced back to above normal 4+’ by Friday. This will ease a bit into next work week. We’re getting a Tropical storm break.

Tropics: VERY Active season with some much needed down time in the East Pacific.

For deeper details GO HERE




Surf Climatology HERE

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.

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

blocking ridge

short-wave tough

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

Links: Get the latest on the Eastern North Pac GO HERE For more on the West Pac Typhoons GO HERE

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