National Weather Service United States Department of Commerce

Surf Forecast for Oahu  Issued: 08/13/2020 03:30:46 AM HST

Surf Discussion for Oahu  Issued: 08/12/2020 02:52:47 PM HST


FZHW52 PHFO xml button
SRFHFO

SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
259 PM HST WED AUG 12 2020

OAHU-
259 PM HST WED AUG 12 2020

NOTE: Please check with local authorities regarding beach closures.

Surf along east facing shores will be 2 to 4 feet tonight, increasing to 4 to 6 feet on Thursday.

Surf along south facing shores will be 1 to 3 feet through Thursday.

Surf along north facing shores will be 2 feet or less tonight, increasing to 4 to 6 feet on Thursday.

Surf along west facing shores will be 2 feet or less through Thursday.

Outlook through Wednesday August 19: Surf will remain below advisory levels along all shores into next week. A northeast swell expected Thursday and Friday will boost surf along east facing shores and may also reach some north shore locations. A small long-period swell from Hurricane Elida is possible over the weekend. Small surf along south facing shores will build starting over the weekend and continuing into next 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.


FXHW52 PHFO xml button
SRDHFO

COLLABORATIVE NEARSHORE SWELL AND WIND FORECAST FOR OAHU
NWS/NCDDC HONOLULU HI
252 PM HST WED AUG 12 2020

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
08/12
4ENE834DOWN10-14EDOWN
2SE913SAME
THU
08/13
5NE947UPLOW9-13ESAME
2SE913SAMELOW
FRI
08/14
5NE1068UPLOW9-13ESAME
2NW1234SAMELOW
1SW1724UPLOW
SAT
08/15
5NE947DOWNLOW10-14ENEUP
1SSW1824UPLOW
1E1413UPLOW
SUN
08/16
4NE834DOWNLOW8-12NEDOWN
2SSW1635UPLOW
2E1234DOWNLOW
MON
08/17
2SSW1535SAMELOW8-12ENESAME

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.... NE exposures topping the heights into weekend when a near average S swell fills in.

DETAILED:. Mid Wednesday on eastern shores has declining breakers from 60-90 degrees under the trade wind swell average. Heights are predicted to build on Thursday.

See the latest NWS State Forecast Discussion for an explanation of the weather features affecting the local winds and skies.

Surface high pressure near 1030 mb has been anchored near 40N, 145-150W to the NE of Hawaii since 8/8. Enhanced winds on the SE side of the high set up a long fetch of strong trades over the 45-60 degree band starting 8/8 from over 1500 nm away. Near gales further away off central California aimed SE of Hawaii, though close enough to add some longer period wind swell to the mix. The main surf source for Hawaii was the broad fetch of strong breezes that shifted westward and has nosed to near 28N, 148W or about 700 nm away Tuesday night. Models show the enhanced fetch becoming narrower within 26-30N as it shifts westward 8/13 N to NNE of Hawaii then weakens to fresh speeds 8/14 once out of the Hawaii swell window.

The closer by fetch of fresh to strong trades 8/12 should trend up the 6-10 second surf on Thursday, with heights growing above average in the afternoon. The event should be filled in by early Friday with 8-12 second wave periods. It should peak mid Friday, and hold above average on Saturday. Heights should fall below average on Sunday then fade by Monday 8/17.

Low odds for below average surf out of 80-90 degrees building 8/15, peaking 8/16, and dropping 8/17 from remote, compact tropical system Elida while off Baja 8/10-11.

Mid Wednesday on northern shores has near flat conditions typical of summer. Similar surf is expected on Thursday morning. Surf should trend up in the PM.

The aforementioned remote NE wind swell should bring up surf for select exposures 8/13-15.

A compact marginal gale moved east from the northern Kuril Islands 8/8 with a weakening trend. This could produce tiny to small surf from 305-315 degrees building late 8/13, peaking 8/14, and fading 8/15.

Mid Wednesday on southern shores has minimal breakers from 140-220 degrees. Surf should remain at a summer minimum on Thursday.

Shorter-period surf from SE trades south of 7N should hold at small or less levels through the period. The dominant background surf should shift to longer-period surf from austral mid latitudes Friday into Saturday.

An active cyclonic pattern began to unfold near New Zealand 8/7. The initial stage had gales in the Tasman Sea. Wave Watch III, WW3, output south of Oahu shows this source arriving on Friday, with inconsistent sets slowly filling in below average out of 208-220 degrees.

The pattern shifted to the SE to E of New Zealand 8/8. An area of severe gales aimed at Hawaii south of 50S to the immediate SE of New Zealand building seas within 25-30 feet. The fetch weakened and aimed less at Hawaii 8/9-10.

The PacIOOS/CDIP American Samoa buoy midday 8/12 showed a rise in the 16-22 second wave period bands, but of low energy. The WW3 had only calculated 3 feet at 17 seconds arriving. The buoy will be monitored since the event is still in the onset stage at this location.

The onset is due locally Saturday 8/15 from 180-200 degrees. It should be filled in by Sunday near the summer average. It should hold about the same into Monday 8/17 from the same direction.

Into the long range, models had been generous 8/7-10 for the second fetch in the series SE of New Zealand, which was predicted to unfold 8/11-12. However, the event turned out to be much weaker than expected. There was a massive area of low pressure E to SE of New Zealand aiming winds at Hawaii 8/11-12, but mostly sub-gale. There were fragmented, short-lived pockets to as much as severe gale. This pattern should at least keep surf near the summer average or a notch under locally 8/18-20 from 180-200 degrees. This estimate can be fine tuned when the swells roll under the American Samoa buoy in a few days.

Also 8/10-12, there was a subtropical gale south of Easter Island that moved favorably for surf in Hawaii with a westward shift. This could bring additional moderate or less surf from 140-150 degrees locally within 8/19-20.

The long wave trough at the jet stream level holds in the models through 8/20 although with a slow eastward shift. This gives potential for more southerly events in Hawaii mostly within background to average, though peak days average to a notch above average from within 170-190 degrees out to 8/21-27.

In the north Pacific, a long spell is modelled with an upper level trough in the Gulf of Alaska stretching SW toward Hawaii. This would keep upstream trades at a minimum locally 8/18-22 leading to near nil surf out of 50-90 degrees during those dates. Weak low pressure systems well N of Hawaii could add low, shorter-period surf from 350-020 degrees within 8/20-22.

Long range forecasts are subject to major revisions.

The next Collaborative Forecast will be updated Friday, August 14.

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 https://www.weather.gov/hfo/marine

NWS Forecasters and NCEI Pat Caldwell

Additional Resources:

Waimea Buoy Mokapu Point Buoy Kaumalapau SW Lanai Buoy Barbers Point, Kalaeloa Buoy Pauwela, Maui Hilo Bay Buoy Kaneohe Bay Buoy Hanalei Kauai Buoy Pearl Harbor Entrance
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

Tides for Honolulu

Tide tables for Hawaii