Surf Forecast for Oahu Issued: 01/18/2020 03:30:52 AM HST
Surf Discussion for Oahu Issued: 01/17/2020 02:23:48 PM HST
FZHW52 PHFO 
SRFHFO
SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
330 AM HST SAT JAN 18 2020
OAHU-
330 AM HST SAT JAN 18 2020
Surf along north facing shores will be 8 to 12 feet through tonight, then will increase to 10 to 14 feet Sunday afternoon.
Surf along west facing shores will be 4 to 6 feet through tonight, then will increase to 6 to 10 feet Sunday afternoon.
Surf along east facing shores will be 3 to 5 feet through Sunday.
Surf along south facing shores will be 1 to 3 feet through Sunday.
Outlook through Saturday January 25: A new north-northwest swell arriving early Sunday may cause surf to reach the High Surf Advisory criteria along north and west facing shores by Sunday night. This swell will gradually lower from Monday through Tuesday. An even larger northwest swell is possible by mid-week, which may cause surf to approach the High Surf Warning thresholds along north and west facing shores from late Wednesday into Thursday. Expect moderate choppy surf along east facing shores into early next week. Small south-southwest swells will maintain background surf along south facing shores through mid-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.
COLLABORATIVE NEARSHORE SWELL AND WIND FORECAST FOR OAHU
NWS/NCDDC HONOLULU HI
223 PM HST FRI JAN 17 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 01/17 | 8 | N | 8 | 4 | 6 | UP | 17-21 | NNE | UP | |
| 4 | ENE | 9 | 3 | 4 | DOWN | |||||
| SAT 01/18 | 10 | N | 10 | 8 | 10 | DOWN | MED | 17-21 | NE | SAME |
| 7 | NE | 7 | 2 | 4 | UP | LOW | ||||
| SUN 01/19 | 3 | N | 10 | 3 | 5 | DOWN | LOW | 17-21 | NE | SAME |
| 7 | NNW | 15 | 12 | 16 | UP | LOW | ||||
| 7 | NE | 8 | 4 | 6 | UP | LOW | ||||
| MON 01/20 | 7 | NNW | 14 | 12 | 16 | DOWN | LOW | 13-19 | E | DOWN |
| 6 | NE | 8 | 3 | 5 | DOWN | LOW | ||||
| TUE 01/21 | 5 | NNW | 11 | 6 | 10 | DOWN | LOW | 9-13 | E | DOWN |
| 4 | NE | 8 | 2 | 4 | DOWN | LOW | ||||
| WED 01/22 | 3 | N | 10 | 3 | 5 | DOWN | LOW | 7-10 | E | SAME |
| 8 | NW | 18 | 16 | 22 | UP | LOW |
LEGEND:
| 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) |
Compass & Swell Shadow Lines for Hawaii
Surf heights will vary between different beaches and at the same beach at different break areas.
DISCUSSION: SUMMARY:. North shores returning to winter.
DETAILED:. Mid Friday on northern shores has choppy breakers at levels below the seasonal average. Short-period breakers are expected to hold on Saturday below average.
Near gales over the 330-360 degree band followed a SE-pushing front 1/15-16 NW to N of Hawaii. ASCAT satellite images Wednesday night and Thursday morning showed a wide, long fetch of near gales nosing to within 500 nm. Closer to Hawaii 1/16-17, winds favored strong levels. The front passed through Oahu Friday morning 1/17. The upstream source to the NNW to N is rapidly fading, as the winds to the N to NNE of Hawaii begin to favor NNE to NE.
Short-period breakers from 330-360 degrees are building mid day. The event should peak just before sunrise Saturday. Given the long, wide fetch, surf should hold on Saturday with only a slow downward trend from 330-360 degrees. Heights should drop much more abruptly Sunday as this event fades and a new longer-period event fills in.
A low gained severe-gale status near 50N on the Date Line 1/16. The 980 mb low is tracking east 1/17 as the fetch aims seas 25-30' at targets just NE of Hawaii and mostly 20-25' at Hawaii beyond 1500 nm away. It should be east of the Hawaii swell window late Saturday.
Long-period swell are predicted to rise mid day Sunday from 320-340 degrees. The event should climb above average in the late afternoon. The peak of the event is predicted pre-dawn Monday from 320-350 degrees. It should hold above average Monday then drop below average Tuesday before fading out Wednesday from 320-360 degrees.
A new low pressure is developing SE of Tokyo 1/17. Models show it gaining storm-force 1/18 near 155E as it tracks east along 40N. It is expected to reach the Date Line early Monday 1/20. Models show the storm-force system continuing east to a position north of Hawaii late Tuesday. This long track will result in a wide swell directional band as it affects Hawaii. Forerunners are due mid day Wednesday with heights climbing above average late afternoon from 290-320 degrees. See the long range below for more comments.
Mid Friday on eastern shores has subsiding breakers from 60-90 degrees, which are due to fade Saturday. More northerly exposures of the east side will trend aforementioned.
Surface high pressure near 32N, 170W NNW of Hawaii 1/17 is modelled to move slowly east over the weekend to a position NE of Hawaii late Monday. The upstream fetch to the NE to ENE is expected to be short so the dominant wave period should remain on the low end, resulting in surf topping out near the trade windswell average for Sunday from 30-60 degrees. Heights should trend down from 40-70 degrees on Monday into Tuesday. Heights should be at an east side minimum by Wednesday 1/22.
Mid Friday on southern shores has near nil breakers. Similar surf is expected on Saturday.
No deep water swell beyond 1' is expected this period, with any low background surf most likely out of the Tasman from 208-220 degrees 1/18-20.
Into the long range, models show tropical cyclone Tino in the SW tropical Pacific 1/17 becoming extratropical while maintaining gales east of New Zealand 1/20-21 as it continues on a SE track. This could bring surf from 180-195 degrees out of the winter slumber locally around 1/27-29. It is too early for size specifics.
The north shore should build well above average Wednesday night 1/22 with a peak centered from 320 degrees Thursday, but energy spread from 290-350 degrees.
Models show a new low pressure system gaining winter-caliber strength 1/21 off the Kuril Islands. It is modelled to occluded near the Date Line 1/23 at hurricane-force. It should send surf locally late Friday into Saturday 1/24-25 to extra- large levels, meaning high enough for breakers on outer reefs. It is expected to be centered from 320 degrees while spread within 300-330 degrees.
Windswell out of 60-90 degrees is predicted to be near a minimum 1/24-26.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Tuesday, January 21.
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 Forecaster and NCEI Pat Caldwell
Additional Resources:
Latest North Pacific Surface Analysis
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