Surf Forecast for O`ahu

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SRFHFO

SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
333 AM HST SAT NOV 18 2017

OAHU-
333 AM HST SAT NOV 18 2017

Surf along north facing shores will be 5 to 7 feet today, rising to 20 to 24 feet Sunday.

Surf along west facing shores will be 2 to 4 feet through Sunday.

Surf along east facing shores will be 3 to 6 feet today, lowering to 2 to 4 feet Sunday.

Surf along south facing shores will be 3 to 5 feet today, lowering to 2 to 4 feet Sunday.

Outlook through Saturday November 25: Advisory-level surf will be likely on Monday and may hold into Tuesday along north facing shores before trending down into midweek. Surf along north facing shores will quickly trend back up and near warning levels once again through the second half of the week as another large north swell fills in and impacts the area. Small south-southwest swells will continue to generate small surf along south facing shores into next week. Surf along east facing shores will trend up and become rough through the second half of the upcoming week and into the weekend as strong trades return.

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
309 PM HST FRI NOV 17 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
11/17
4NNE1368UP9-13NEDOWN
6NE946DOWN
1SSW1735UP
SAT
11/18
4NNE1157DOWNMED9-13NSAME
3NE924DOWNLOW
2SSW1435SAMELOW
SUN
11/19
12N132024UPMED11-16NNWSAME
1SSW1424DOWNLOW
MON
11/20
10N121620SAMELOW11-16NNWSAME
1SSW1424SAMELOW
TUE
11/21
9N121216DOWNLOW11-16NNESAME
1SSW1734UPLOW
WED
11/22
6N1068DOWNLOW11-16NESAME
5N17812UPLOW
5NE612UPLOW
1SSW1524SAMELOW

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:. N swell spell.

DETAILED:. Mid Friday on northern shores has breakers from 010-030 degrees at levels below the Fall average. Heights should remain below average on Saturday from the same direction.

A long-lived surface low pressure in the Gulf of Alaska 11/10-15 has kept the NNE event up locally all week. NOAA NE buoy 51000 shows NNE energy in the 12-14 second band rising 11/17. This was due to an increase to gales in the low off Oregon 11/13-15. The system weakened as it moved into the NW USA 11/16.

The PacIOOS Waimea and Mokapu, Oahu late morning 11/17 readings show an upward trend in the 12-14 seconds. This event is expected to peak late Friday and trend down through Saturday from 010-030 degrees.

The persistent north Pacific jet stream pattern since last week has maintained a block over the central Aleutians and troughs in the Gulf of Alaska. Models show it holding into next week. This is keeping WNW to NNW surf at a seasonal minimum and dominant swell out of the N to NNE.

The next in the series of surface lows digging SSE from the eastern Aleutians 11/15 was about 20 degrees longitude further west than previous systems that gave NNE swell. Thus, more straight N direction is expected.

It had the largest area of gales Wednesday night through Thursday night stretching from near the eastern Aleutians to 40N. This source alone would give above average surf for Sunday with moderate wave periods within 13-15 seconds from 350-010 degrees.

As of Friday morning the wind speeds are mostly near gales as the center of low pressure continues to move southward. Models show the head of the fetch to within 400 nm of Hawaii on Saturday with strong to near-gale winds. This will add short- to moderate- period swell of 9-13 seconds on Sunday, also from 350-010 degrees.

The combined remote and nearby generated swell should make a less organized breaker pattern Sunday 11/19 under a moderate onshore winds-- adding chop. See the latest NWS State Weather Discussion regarding the trend and uncertainties in local winds and weather over the weekend into next week.

Models show a cut-off upper level low above the surface low 11/14-16 to the immediate north of Hawaii. Such patterns change slowly. It is modelled to maintain strong to near gale winds on the NW to NE side of the surface low over the 350-010 degree band. This should maintain above average, shorter- period N swell Monday into Tuesday, under a local gentle to moderate, N-component, chop-producing wind. The surf should drop below average on Wednesday as a new event fills in.

The next in the series of lows in the Gulf of Alaska is expected to shift eastward to south of Anchorage, Alaska with a SSE track. Since it is expected to be further east, the local swell direction should return to dominant NNE. The surface winds are modelled to be much stronger than the preceding system. Severe gales with pockets of storm- force winds are expected to aim highest slightly east of Hawaii north of 40N, though a large, wind fetch of gales aimed directly at Hawaii with the head of the fetch about 700 nm away on Tuesday. Long-period forerunners from 000-020 degrees should fill in locally Wednesday mid day, with surf climbing above average late Wednesday. More comments below.

Mid Friday on eastern shores has declining shorter-period swell of 8-10 seconds from 30-50 degrees at levels near the trade windswell average. It should drop below average on Saturday.

The aforementioned N to NNE events should keep active surf for more northerly exposures of the east side through the period.

Moderate NE trades Wednesday should slowly return trade windswell from 40-60 degrees 11/22.

Mid Friday on southern shores has inconsistent, low, long-period swell from within 180-220 degrees at levels. Similar surf is predicted for Saturday.

The austral Spring in the mid latitudes SW to SE of New Zealand have been active over the past 10 days. Given the near nil typical size for this time of year, surf has been higher than normal. More of the same is expected into the long range.

NOAA southern Hawaii buoys show an upward trend in the 15-17 second bands into 11/17. This long-period energy was generated in the Tasman Sea and just to the east of the New Zealand shadow 11/8-9. As the associated low pressure moved east, the surface winds weakened to marginal gales. A wide, long fetch over the 180-200 degree band held 11/10-15 that should keep a background surf pattern for the rest of the period. Another strong low in the Tasman 11/13-14 could add additional low, long-period swell from 208-220 degrees locally 11/21-22.

Into the long range, more of the same from the SSW with small breakers for zones of high refraction along southern exposures 11/23-27.

North shores on 11/23 should climb from 000-020 degrees into extra- large levels, meaning high enough for breakers on outer reefs. With proximity, there should be short- to moderate-period swell arriving simultaneously, making for less organized breakers. It should slowly trend down to near average by late 11/24.

A compact severe gale in the Kamchatka corner is modeled for 11/21-22. It could make below average, long-period swell from 310-320 degrees roughly 11/25. Another Gulf of Alaska low is due roughly 11/23-25 trending N to NNE surf up around 11/26-27.

Fresh to strong ENE trades 11/24 should build breaker above the trade windswell average by 11/25 from 50-80 degrees.

Long range forecasts are subject to low confidence.

This collaborative forecast will resume on Monday, November 20.

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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