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Weather

Surf Advisory and Warning Criteria
Location/shoreline Advisory Warning
North-Facing Shores- 15 Feet faces (8' Local) 25 Feet faces (15' local)
West-Facing Shores - 12 Feet (7' local) 20 Feet (12' local)
West-Facing- Big Is.- 8 Feet (4'+ local) 12 Feet (7' local)
South-Facing Shores- 8 Feet (4'+ local) 15 Feet (8' local)
East-Facing Shores- 8 Feet (4'+ local) 15 Feet (8' local)

Big Picture

BIG PICTURE: Friday 9/23/17

NPAC: The 130kt Jet is lower with some mostly zonal flow from Japan to near our 160W longitude. But we need some 160-180+kts or more energy in these upper regions 30,000 ft up.

A huge area of High pressure persists for a majority of the East Pac where the Jet bumps up and over.

By next week Tuesday the 26th there’s a dip or trough to our North and the Jet gains momentum which allows for a surface low to spawn and bring some surf next weekend. This dip is pronounced into next wkend.

The Jet moves NE off Japan is finally up to 160kts by Saturday the 30th but it’s distant and is only steering surface storms into the Bering sea.

#1 Recently/currently: We’ve had a windy trade week with small surf including the short period WNW that filled Thursday to 3’; it veered NW into Friday holding the same head high range. This small Fall event was triggered by a small eastbound Low this past Sunday about 1500 miles NW. This fades all weekend esp by Sunday but will at least be ride-able. The work week gets even worse. Tho’ we do see some soft 2’ reinforcement of a 10 sec NNW Monday-Wednesday. But it’s mostly ‘background’ level just to keep Menehune’s stoked.

#2 Next: Low pressures go into a quiet period from Thursday22nd-Monday25th when a tiny short fetch 1500 miles NNW of us pops from a fast east tracking weak Low. It may bring some 3’ surf at 10 sec later Tuesday into Wednesday the 28th.

#3 Last: A better bet NW comes from a Low spotted Tuesday about 2000 miles NW. It’s crossing the dateline Wed-Thurs. the 28th when the fetch strengthens to 50kts just on our side of the dateline just 900 miles NW. The fetch gets support via increased pressure gradient between the high pressure to the NW of the Low into Friday. Look for a fast rise from 2-4’ surf early thru the first half of Saturday the 30th then climb to almost 6’ the second half, ending up with the swell of 6’ at 11 sec Sunday or 3-5’ surf average. This longer-lasting event should be a few days. It will start off NW and end up NNW by Tuesday.

SPAC: The JETSTREAM looks bad for SSW swell production the entire 7-day model run. This reflects our transition into Fall. Though there’s energy (180kts) for the zonal Northern Branch we don’t get the proper positioning of surface Lows. The southern branch way down under is terrible: weak and zonal, all the way until day 7 when, far to the SE it points NE to the Americas. It’s mostly out of our window, however, models hint that the storm spawned will be big and strong enough for a long period sideband SE swell Oct 7-9. Too early to call.

#1 Recent + Today: It’s been tiny but rideable from the generic SSE this week with averages of 2.5’ early and 2’ later by Friday

#2 Next: A Taz Low centered at bottom of Tasmania tracks mostly ENE from Friday-Sat. 15-16th. So far models say less than 1.5’ deep water at 14sec Sunday the 24th. Meaning 2’ surf average More Monday into Tuesday. Sets slow to rise and be 2x an hour to start which is your typical Taz. There was also a compact Low to the SE of Tahiti last weekend which may keep 2’ surf in the mix Sunday into Tuesday

#3 Next: Another smaller Taz source was seen Wednesday the 20th. So far WW3 has less than 1’ of deep water at 15 sec. Not likely enough to make it waist high this Wednesday-Friday more than once an hour.

#4 Last: A big Low come up off the Ross Ice Shelf Saturday the 30th but it’s far (too far) SE and if we get anything oct 7th it will only be sideband swell thanks to swell dispersion (think: a tossed pebble into a pond).  At any rate, WW3 model fantasy does have this peak with 2’ deep water at 15 sec Sunday the 8th which if it pans out would mean solid 3’ for SE focal reefs like Kewalos, Courts, Kaisers, DH, Sandys…

TRADE SWELL

Trades swell has been good this past week but is heading just below averages from Sunday into next week Friday! There’s a Low’s weak surface trough pushing our high east and weakening it and it’s ridge down near the Islands from the NW. By Sunday eve the trades will be light enough for sea breezes thru Wednesday….so small wind swell, but clean conditions. Good diving for Windward all week.

TROPICS: Nothing today nor for the weekend.

We had Typhoon Talim slamming Japan Monday and today it’s all but finished its destructive journey.

Get the latest on the tropics at www.hurricanes.gov

The Central Pacific Hurricane Center outlook for the 2017 Central Pacific Hurricane Season calls for 5 to 8 tropical cyclones to either develop or cross into the Central Pacific with a 40% chance for an above-normal season, a 40% chance for a normal season, and a 20% chance for a below-normal season. An average season has 4 to 5 tropical cyclones, which include tropical depressions, tropical storms, and hurricanes.

A tropical depression forms when a low-pressure area is accompanied by thunderstorms that produce a circular wind flow with maximum sustained winds below 39 mph. An upgrade to a tropical storm occurs when cyclonic circulation becomes more organized and maximum sustained winds gust between 39 mph and 73 mph. A tropical storm is then upgraded into Category 1 hurricane status as maximum sustained winds increase to between 74 mph and 95 mph. (The highest classification in the scale, Category 5, is reserved for storms with winds exceeding 156 mph). 

Tropical cyclones go by many names around the world, and the terminology can get confusing. Once a tropical cyclone strengthens to the point where it has gale-force winds—39 mph or greater—it becomes a tropical storm. A storm that reaches tropical storm strength usually gets its own name to help us quickly identify it in forecasts and warnings. Once a tropical storm begins producing sustained winds of around 75 mph, we call the storm a typhoon in the western Pacific near Asia and a hurricane in the oceans on either side of North America. A “typhoon” and a “hurricane” are the same kind of storm, they just go by different names…it’s only a matter of geography.

NWS criteria for High Surf Advisories & Warnings.

In coordination with civil defense agencies & water safety organizations in Hawai`i, the NWS uses the criteria below for the issuance of High Surf Advisories & Warnings in coordination with civil defense agencies & water safety organizations in Hawai`i.

All surf height observations & forecasts are for the full face surf height, from the trough to the crest of the wave.

Advisory and Warning Criteria Location 

Warning North-Facing Shores 15 Feet 25 Feet

West-Facing Shores - Remaining Islands 12 Feet 20 Feet

West-Facing Shores - Big Island 8 Feet 12 Feet

South-Facing Shores 8 Feet 15 Feet

East-Facing Shores 8 Feet 15 Feet

'Travel Time' Buoy 51101 to Waimea Buoy. Distance: 269 nautical miles (~310 miles). Angle: 307 deg
Wave   Wave        Wave   Depth      Wave Direction (deg)----------
Period  Length      Speed  Shallow   295,  305,  315,  325,  335,  345,  355
(s)       (ft)    (nm/h)  (ft)                  Travel Time (hours)----------
10sec. 512.  15.        256.                   17.3, 17.7, 17.6, 16.9,  15.7,   14.0,   11.9
12sec. 737.  18.        369.                  14.5,  14.8, 14.6, 14.0, 13.0,  11.6,  9.9
14sec. 1003. 21.      502.                  12.4,  12.7, 12.5,  12.0,  11.2, 10.0,  8.5
16sec. 1310. 24.      655.                  10.8, ,1 1.1,  11.0,  10.5,   9.8,   8.7,  7.4
18sec. 1658. 27.     829.                   9.6,    9.8,     9.8,   9.4,   8.7,   7.8,  6.6
20sec. 2047. 30.    1024.                8.7     8.9      8.8     8.4    7.8    7.0   5.9
22sec. 2477. 33.    1239.                 7.9     8.1       8.0     7.7    7.1     6.3   5.4
24sec. 2948. 36.    1474.                7.2      7.4      7.3     7.0   6.5     5.8    4.9



Tropical Storms - wind 39-73 mph (34-63 kt)

Category 1 - winds 74-95 mph (64-82 kt)

Category 2 -winds 96-110 mph (83-95 kt)

Category 3 -winds 111-130 mph (96-113 kt)

Category 4 - winds 131-155 mph (114-135 kt)

Category 5 -winds 156 mph and up (135+ kt)

Please visit the Central Pacific Hurricane Center website at www.weather.gov/cphc for the most recent bulletins.

ENSO is a single climate phenomenon, it has three states or phases. The two opposite phases, “El Niño” and “La Niña,” require certain changes in both the ocean and the atmosphere because ENSO is a coupled climate phenomenon.  “Neutral” is in the middle of the continuum. The MJO (Madden-Julian Oscillation) is an eastward moving disturbance of clouds, rainfall, winds, and pressure that traverses the planet in the tropics and returns to its initial starting point in 30 to 60 days, on average, unlike ENSO which is stationary. In a nutshell, more active means more surf.
Kelvin wave (A Kelvin wave is a wave in the ocean or atmosphere that balances the Earth's Coriolis force against a topographic boundary such as a coastline, or a waveguide such as the equator. A feature of a Kelvin wave is that it is non-dispersive, i.e., the phase speed of the wave crests is equal to the group speed of the wave energy for all frequencies. This means that it retains its shape as it moves in the alongshore direction over time.)