BIG PICTURE: Brief General Update Thursday 7am
The long-lasting ENE tops the list but a notch down with 3-5′ and some possible plus sets at Makapu’u. These wind waves from the strong 1033mb high to our North are still wrapping into Laniakea at up to 1-2-3′ but it’s disjointed & bumpy. Buoys all show only windswell.
Next, looking good now for solid 15 sec NNW surf at 4-6+’ Friday the 20th. Deepwater 18-20 sec Forerunners come Thursday afternoon with NW surf hitting solid 4′ by sundown, maybe earlier thanks to the long period. Surf source: The 45-55kt storm was way up off Kamchatka Monday and was strongest Tuesday as it crossed the dateline; its track was zonal or west to east thanks to the zonal Jetstream which is currently sending most swell to our NE. The fetch on it’s West flank was decent but some of this swell will be sideband-swell dispersion as plenty power is off to the NW Pacific coast. The swell direction will be veering North into Saturday.
Next, an upgrade for an advisory level 6-8+’ NNW at 16-18 sec is projecting its 20 sec forerunners Sunday the 22nd with a lite SE flow to winds. The peak will be Monday again over 8′ and by Tuesday afternoon surf will drop a lot. The source Low tracks ESE off Kamchatka with 45-55kts from Thursday the 19th. By Friday it crosses the dateline with 28-30’ seas and has better ‘aim’ at us than the former Low. Thus, a legit high surf adv. episode. Winds to be variable with possible Kona flow Monday-Tuesday due to a nearby trough or elongated area of low pressure bring some weather too. From Sunday-Tuesday
Last look: WW3 models went from ‘whoa’ to ‘oh well’. Last weekend we had a what we called a “10% chance” of possible 20’ surf Saturday 10/28. But, sure enough, the ‘gender bender’ Low Typhoon Lan (changing from ‘warm core’ to ‘cold core’) (read below) ends up getting shaved up during its partial track over Japan. Then the former Typhoon moves East closer to us but after this, its forecasted to weaken to just 35kts. On late Wednesday 25th, the fetch is on our side of the dateline with a long follow up fetch behind the main source. Saturday afternoon the 28th, surf should hit just 5-7′ surf at 14sec. With some smaller surf up to 5′ with a long period WNW from the earlier phases of the storm off Japan. We are more confident now as we’re getting closer in time.
We’re in a zonal Jet up near the Aleutians should last into this work week which will allow the High to remain dominant. Thus the long-term strong trades.
Town: The SSE that peaked Monday up to isolated 7′ is gone. The surf for Wednesday was mostly 1-2′ occ 3′ with strong gusty ENE trades. Buoys dont even show the short 11 sec SSE as they’re overrun by the windswell.
The source for our surf earlier was a powerful Low on the heels of the preceding storm. This Low tracked North in the same zone Sunday-Tuesday (8-10th) & occluded (stalled and broadened) building up to 40′ seas. Buoys reached 4′ of deep water!
Southern Sources go quiet for a while Thursday-Saturday when Sunday an eastbound storm SE of NZL sends up some SSW surf up to 3′ on Monday the 23rd. 18sec forerunners for later Sunday 22nd.
Not a bad run for October.
Windward: Strong ENE upstream & local Trades continue for 2 more days Thanks to the big 1033mb High-pressure to our North Their waves ramped up surf to 8′ Monday at the peak times way out there (15′ faces or warning levels which were never posted). Tuesday 17th it was still 6’+ local scale…well above advisory surf which only needs 8′ faces to go up. Surf is still 5′ solid but will finally drop by Friday to 2-4′ and then 3′ over the weekend as trades weaken to variable due to an approaching trough. By Sunday they’ll be lite SE flow with chance of seabreezes. SW Kona winds maybe fresh paced Monday.
Tropics (West) active this week.
As of Thursday Typhoon Lan is centered about 680 miles south-southeast of Naha, Okinawa. Lan is tracking toward the north at about 7 mph, having highest-sustained winds of 80 mph. Strengthening is forecast to occur within 12-24 hours, potentially raising intensity to that of a Category 4 hurricane by Friday. The movement will continue to be toward the north through the end of the week.
From Sunday into early next week, Lan is expected to track northeastward to the coast of eastern Japan, near Tokyo. We may see some small-moderate WNW from this phase.
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.
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 to 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