Oahu Surf Conditions
Surf along south facing shores will be 1 to 3 feet tonight through Tuesday.
Surf along north facing shores will be 2 feet or less through Tuesday.
Surf along east facing shores will be 2 to 4 feet through Tuesday.
Surf along west facing shores will be 2 feet or less through Tuesday.
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.
|SWL HGT||Open ocean swell height measured from trough to crestin feet located 20 nautical miles offshore|
|DMNT DIR||Dominant direction typically +/-10 degrees in 16 compasspoints|
|DMNT PD||Dominant period in seconds|
|H1/3||Significant wave height in the surf zone|
|H1/10||Average height in the highest one-tenth waves in the surfzone|
|HGT TEND||Height tendency of swell (valid values: UP/DOWN/SAME)|
|PROB||Probability of occurrence (valid values: HIGH/MED/LOW)|
|WIND SPD||Open water wind speed measured in knots located20 nautical miles offshore|
|WIND DIR||Wind direction in 16 compass points|
|SPD TEND||Wind speed tendency (valid values: UP/DOWN/SAME)|
DISCUSSION: SUMMARY....Dog days of summer.
DETAILED:. Mid Monday on northern shores has typical summer conditions. Near nil surf should hold on Tuesday.
No surf beyond tiny is expected from WNW to NNE this period. Exposures to trade wind swell are expected to top the heights at small or less this week as described below.
Mid Monday on eastern shores has decreasing breakers from 60-90 degrees below the trade wind swell average. Heights are expected to nose up a notch on late Tuesday.
See the latest NWS State Forecast Discussion for synoptic details driving the trend and uncertainties of trade winds over Oahu this period.
The seasonally, semi-permanent, NE Pacific, surface high pressure system is entrenched over a large area centered near 40N within 140-150W. Models show the center moving little while triggers for surf in Hawaii depend more on tropical interaction.
For 7/12-14, breakers from trade wind swell have been on a slow decline due to one of those tropical features. In this case, it was a TUTT, or tropical upper tropospheric trough, set up over the trade wind belt aimed at Hawaii west of 140W within 20-30N. This feature weakens the surface pressure gradient, which in turn, lightens the wind; hence, it lowers the surf potential in Hawaii from trade wind swell. The feature has been moving steadily west 7/10-13 and is north of the state Monday. Models show it continuing a slow westward drift NW of Hawaii 7/14-16.
On the east side of the TUTT, where a ridge ruled the upper levels, enhanced surface trades within fresh to strong covered a wide fetch within 20-30N with the head of the west-most fetch near 140W 7/11. ASCAT satellite 7/11-12 showed a large area of strong trades beyond 800 nm away. The pattern has shifted west, with the morning ASCAT 7/13 showing the head of the fresh to strong trades near 150W, or about 500 nm away from Oahu. These stronger trades are not expected to reach Oahu as described in the NWS State Forecast Discussion. However, the remote wind swell is expected to turn up the east side surf midweek.
Breakers from wind swell out of 60-90 degrees are modelled to increase locally late Tuesday, peak late Wednesday above average, then trend down slightly Thursday to Friday.
Tropical system Cristina 7/8-13 in the eastern tropical Pacific has been too compact and too far away to expect any breakers locally beyond the trade wind swell source aforementioned. Models show a smaller fetch of enhanced trades on the N side of the weakening Cristina nosing to within 300 nm within 7/16-17. This could keep the near average event locally 7/17-18. Stay tuned for updates in case the system surpasses the recent model expectations.
Mid Monday on southern shores has breakers at a seasonal minimum. Low conditions are expected to hold on Tuesday.
Marginal gales in the Tasman Sea 7/4-7 could make for low, inconsistent surf locally out of 208-220 degrees 7/13-16 as it competes with the SE trade wind swell to be the dominant background source. The Tasman low moved east of New Zealand 7/7-9, though was mostly sub-gale breezes. This could add a pinch of background from 185-200 degrees 7/17 locally.
A short-lived, compact, severe-gale aimed highest seas to near 25 feet at the Americas south of 55S to the S to SE of New Zealand 7/10-11. The onset stage is due locally 7/18 from 185-200 degrees.
Into the long range, the aforementioned New Zealand source should be filled in on 7/19 and peak late 7/19 near to a notch under the summer average. It should fall below average 7/20.
Otherwise, no significant sources are seen Downunder this week. Southerly surf should hold below average locally 7/21-24.
No surf beyond tiny is expected from WNW to NNE 7/19-24.
East side is modelled to trend up toward average from 40-70 degrees 7/21-22.
Long range forecasts are subject to low confidence.
The next Collaborative Forecast will be updated Wednesday, July 15.
This forecast was produced through the collaborative efforts of NWS and NCEI. Please send suggestions to firstname.lastname@example.org or call the Warning Coordination Meteorologist at 808-973-5275.
ADDITIONAL RESOURCES: See https://www.weather.gov/hfo/marine