Surf Forecast for O`ahu

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SRFHFO

SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
350 AM HST MON OCT 23 2017

OAHU-
350 AM HST MON OCT 23 2017

Surf along north facing shores will be 10 to 14 feet today, decreasing to 8 to 10 feet tonight, and then building to 10 to 14 feet Tuesday.

Surf along west facing shores will be 6 to 10 feet today, decreasing to 4 to 6 feet tonight, and then building to 6 to 10 feet Tuesday.

Surf along south facing shores will be 5 to 7 feet through Tuesday.

Surf along east facing shores will be 1 to 3 feet today through Tuesday.

Outlook through Monday October 30: The current northwest swell will be on the decline today, with a larger northwest swell expected to begin to build in on Tuesday that will produce surf well above the advisory level threshold along north, and possibly west, facing shores Tuesday and Wednesday. An even bigger northwest swell near the end of the week may produce warning level surf. The south swell will persist into Wednesday with surf near the advisory level, and then decline through the end of the week.

Surf heights are forecast heights of the face, or front, of waves. The surf forecast is based on the significant wave height, the average height of the one third largest waves, at the locations of the largest breakers. Some waves may be more than twice as high as the significant wave height. Expect to encounter rip currents in or near any surf zone.


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SRDHFO

COLLABORATIVE NEARSHORE SWELL AND WIND FORECAST FOR OAHU
NWS/NCDDC HONOLULU HI
310 PM HST FRI OCT 20 2017

This collaborative forecast will be updated Monday through Friday at 300 PM when Pat Caldwell is available.

FORECAST
DATE
SWL
HGT
DMNT
DIR
DMNT
PD
H
1/3
H
1/10
HGT
TEND

PROB
WIND
SPD
WIND
DIR
SPD
TEND
1PM
10/20
5NNW14810DOWN22-27NEDOWN
10NE9710SAME
SAT
10/21
3NNW1246DOWNLOW13-19EDOWN
7ENE846DOWNMED
2SW1534UPLOW
SUN
10/22
6NW171214UPMED4-6VRBSAME
4ENE824DOWNLOW
2SSW1948UPLOW
MON
10/23
7NNW151216DOWNMED9-13SWUP
3SSW1648SAMELOW
TUE
10/24
9NNW121016UPLOW11-16NUP
3SSW1447DOWNLOW
1W1824UPLOW
WED
10/25
9NNW121016DOWNLOW7-10NDOWN
2S1335DOWNLOW
3SE1548UPLOW
2W1846SAMELOW

LEGEND:

SWL HGTOpen ocean swell height measured from trough to crestin feet located 20 nautical miles offshore
DMNT DIRDominant direction typically +/-10 degrees in 16 compasspoints
DMNT PDDominant period in seconds
H1/3Significant wave height in the surf zone
H1/10Average height in the highest one-tenth waves in the surfzone
HGT TENDHeight tendency of swell (valid values: UP/DOWN/SAME)
PROBProbability of occurrence (valid values: HIGH/MED/LOW)
WIND SPDOpen water wind speed measured in knots located20 nautical miles offshore
WIND DIRWind direction in 16 compass points
SPD TENDWind speed tendency (valid values: UP/DOWN/SAME)

Compass & Swell Shadow Lines for Hawaii

Oahu Surf Climatology

Surf heights will vary between different beaches and at the same beach at different break areas.

DISCUSSION: SUMMARY:. Surf from around the compass.

DETAILED:. Mid Friday on northern shores has breakers near the October average from 330-360 degrees. Heights should fall below average on Saturday.

A zonal jet stream 10/16-20 has steered a pair of storm-force surface low pressures eastward near 50N from Kamchatka to the Gulf of Alaska. This should make for back to back episodes.

The first event peaked locally Friday morning 10/20. With the fast eastward track, the event should be short-lived. Heights should fall below average Saturday 10/21 from the same direction and fade on Sunday as the next event arrives.

The second surface low gained storm force further west more in the Hawaii swell window 10/18-19. It should produce larger surf.

The system crossed the Dateline early Friday 10/20. JASON altimeter 2017-10-20-12Z validated the Wave Watch III estimate of seas near 30 feet on the western side of the highest seas near 45N on the Date Line. This increases confidence in the local surf estimate. The system is expected to move east of the Hawaii swell window late Friday into early Saturday.

Long-period forerunners from 315-330 degrees should fill in on Sunday, with breakers above average by late Sunday AM. The event should peak near sundown on Monday from 325-345 degrees. It should drop below average by Tuesday morning as a new shorter-period event rises locally.

Models show a strong surface high pressure near 40N on the Date Line and a low pressure forming north of Hawaii 10/22-23. A long fetch of strong to near gale winds over the 330-350 degree band is modelled to nose to within a few hundred miles to the NNW of Hawaii by late Monday.

Proximity should allow the shorter-period event to build above the October average with a steep rise Tuesday morning. The event should hold about the same into Wednesday. This latter event is of lower confidence. Stay tuned for updates.

Mid Friday on eastern shores has rough, above average breakers from 20-60 degrees. Surf is predicted to decline on Saturday.

ASCAT satellite Thursday night 10/19 showed a large area of strong breezes to the ENE to NE of Hawaii from 40-60 degrees. The 10/20 morning ASCAT pass shows this upstream batch has already weakened down to within moderate to fresh. Models show a continued weakening of the upstream source on Saturday.

Breakers from trade windswell should drop to near the trade windswell average on Saturday from 40-60 degrees. It should fall below average by Sunday and hover near a windward side minimum 10/23-25.

More northerly exposures of the east side should trend aforementioned.

Mid Friday on southern shores has breakers near a seasonal minimum. Low odds for a small increase on Saturday.

Gales in the Tasman Sea 10/13-14 could bring a small swell locally 10/21 from 208-220 degrees. A larger event is on its heals.

The Tasman system 10/14 increased to storm-force with seas within 30-40 feet as the pattern moved into the Hawaii swell window S to SE of New Zealand last Saturday night into Sunday morning 10/14-15. Proximity to New Zealand lessens the fetch width and in turn adds greater error bars to the local surf estimate.

The PacIOOS American Samoa buoy registered the long-period swell 10/19, which increases confidence for arrival in Hawaii. The magnitude suggests surf should at least surpass the summer average Sunday into Monday.

The roughly 24-hour onset phase could begin as soon as Saturday PM with low, infrequent breakers. The event should be filled in by Sunday PM from 190-200 degrees. It should peak early Monday above the summer average.

Once E to SE of New Zealand 10/16-17, a long, wide fetch of lower-end gales set up over the 185-200 degree band. This source should keep surf near to above the summer average 10/24-25 from 180-200 degrees.

A compact gale SW of Easter Island 10/18-19 had direct aim at Hawaii. Surf near to above the summer average is predicted to pick up 10/25 from 140-150 degrees.

Super Typhoon Lan NE of the Philippines 10/20 is modelled to track northward as it maintains strength. Low, long-period swell from 270-280 degrees could pick up locally Tuesday and build into Wednesday.

Into the long range, Lan is modelled to become extratropical to the NE of Japan 10/23-24 with an eastward track. Models are mixed on strength and position, though all suggest above average, long- period swell to fill in mid 10/26 and peak within 10/27-28 from WNW to NNW. The more westerly component should continue locally 10/26-28.

Surf from the southern hemisphere should trend down 10/26-27 to levels below average.

Trade windswell from 40-90 degrees should remain near an east side minimum.

Long range forecasts are subject to high uncertainty.

This collaborative forecast will resume on Monday, October 23.

This forecast was produced through the collaborative efforts of NWS and NCEI. Please send suggestions to w-hfo.webmaster@noaa.gov or call the Warning Coordination Meteorologist at 808-973-5275.

ADDITIONAL RESOURCES: See http://www.prh.noaa.gov/hnl/pages/marine.php

NWS Forecaster and NCEI Pat Caldwell

Additional Resources:

Waimea Buoy Kailua Buoy Lanai Buoy Barbers Point #2 Pauwela, Maui Hilo Bay Buoy Kaneohe Bay Buoy Hanalei Kauai Buoy Kilo Nalu
Buoy 51001 Buoy 51101 Buoy 51000 Buoy 51100 Buoy 51002 Buoy 51003 Buoy 51004

Latest North Pacific Surface Analysis

Upcoming tides for select Hawaii locations

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