Surf Forecast for Oahu Issued: 05/25/2019 03:30:29 AM HST
Surf Discussion for Oahu Issued: 05/24/2019 03:12:09 PM HST
FZHW52 PHFO 
SRFHFO
SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
330 AM HST SAT MAY 25 2019
OAHU-
330 AM HST SAT MAY 25 2019
Surf along south facing shores will be 4 to 7 feet through tonight, then increasing to 5 to 8 feet Sunday.
Surf along north facing shores will be 4 to 6 feet through Sunday.
Surf along west facing shores will be 2 to 4 feet through tonight, then increasing to 3 to 5 feet Sunday.
Surf along east facing shores will be 4 to 6 feet through tonight, and 3 to 5 feet Sunday.
Outlook through Saturday June 01: A south-southwest swell arriving today is expected to keep surf near the High Surf Advisory criteria along south facing shores from Sunday through Memorial Day. The south-southwest swell will gradually fade on Tuesday, while a new moderate south swell begins to fill in. This south swell should maintain moderate surf along south facing shores late next week. A moderate, short-period northwest swell will produce a bump in surf heights along north and west facing shores through mid-week. The trade wind swell will gradually lower early next week, but it may increase late next week as the trades strengthen again.
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
312 PM HST FRI MAY 24 2019
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 05/24 | 3 | NW | 11 | 3 | 5 | UP | 10-15 | E | UP | |
| 6 | E | 8 | 3 | 5 | UP | |||||
| 3 | SSW | 14 | 4 | 6 | DOWN | |||||
| SAT 05/25 | 4 | NW | 12 | 5 | 7 | UP | HIGH | 10-15 | E | SAME |
| 6 | E | 9 | 4 | 6 | SAME | MED | ||||
| 3 | SSW | 12 | 3 | 5 | DOWN | LOW | ||||
| 2 | SSW | 20 | 4 | 6 | UP | LOW | ||||
| SUN 05/26 | 4 | NW | 12 | 5 | 7 | DOWN | MED | 9-13 | E | SAME |
| 4 | E | 9 | 3 | 5 | DOWN | LOW | ||||
| 4 | SSW | 16 | 6 | 8 | UP | LOW | ||||
| MON 05/27 | 3 | NNW | 11 | 3 | 5 | DOWN | LOW | 9-13 | E | SAME |
| 4 | E | 7 | 1 | 2 | DOWN | LOW | ||||
| 4 | SSW | 15 | 6 | 8 | DOWN | LOW | ||||
| TUE 05/28 | 3 | NNW | 11 | 3 | 5 | UP | LOW | 9-13 | E | SAME |
| 4 | E | 7 | 1 | 2 | SAME | LOW | ||||
| 3 | SSW | 12 | 3 | 5 | DOWN | LOW | ||||
| 2 | S | 16 | 3 | 6 | UP | LOW | ||||
| WED 05/29 | 3 | NNW | 10 | 3 | 5 | DOWN | LOW | 10-15 | E | UP |
| 4 | E | 7 | 1 | 2 | SAME | LOW | ||||
| 3 | S | 14 | 4 | 6 | SAME | 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:. Active surf pattern over the holiday weekend.
DETAILED:. Mid Friday on northern shores has rising breakers from 300-320 degrees. Heights should trend up into Saturday.
A low pressure occluded near 40N, 175W Tuesday 5/21. The pattern remained stationary into Friday 5/24. Models show this Aleutian low system to have a slow northward shift 5/25 with reinforcement short-waves spaced a few days apart feeding the upper level gyre to keep continued surface low pressure systems with winds aimed at Hawaii. This should make for a long-lived spell of NW to NNW surf locally into the long range.
PacIOOS/CDIP Waimea, Oahu buoy Friday 5/24 mid day shows the new swell is filling in. The event should climb into Saturday above the May average from 300-320 degrees and hold about the same into Sunday. Heights should slowly trend down late Sunday into Monday to near the average from 300-330 degrees.
The first reinforcement surface low pressure area is modelled to have strong breezes with pockets to near gales near 1200 nm away 5/25-26 to the NNW of Hawaii north of 40N south of the Aleutians. This should keep near average surf locally Tuesday into Wednesday from 315-330 degrees.
Mid Friday on eastern shores has rising breakers from 70-90 degrees to near the trade windswell average. Heights should trend up into Saturday from the same direction.
Surface high pressure has been anchored near 40N, 140W this week. A long, wide fetch of fresh to strong trades set up within 20-25N, 140-155W. Wave Watch III predicts this upstream windswell source to peak locally on Saturday with breakers above average.
The Friday morning 5/24 ASCAT showed the trades in the fetch to the east of Hawaii on a weakening trend. Models show further weakening into the weekend. Breakers from E windswell should taper down Sunday to below average by late in the day. Low breakers should be the rule for Monday into Wednesday.
Mid Friday on southern shores has breakers from 180-200 degrees at levels above the seasonal average. Heights should trend down Saturday morning then trend up again in the afternoon.
The New Zealand south swell source area was active 5/14-20 within 35-70S, 160E to 160W. This places the local swell out of 180-200 degrees. A sequence of fetches filled the area and have been keeping active surf this week with overlapping events. The last one is expected to be the largest locally peaking Sunday into Monday.
This final source over the 180-200 degree band had a long, wide fetch 5/17-20 with severe gales growing seas to near 30 feet. Those were weaker winds relative to the Mothers Day swell source near the same area, so this event is expected to be a notch lower locally. As with the Mothers Day event, and as is most often the case from the New Zealand source region, highest aim of seas and swell were off to the SE of Hawaii. This places higher error bars on the local surf estimate.
The PacIOOS/CDIP American Samoa buoy registered the rise of this event with 6 feet deep water swell at 15-17s building 5/22 and slowly dropping 5/23-24. These wave periods reflects the severe gale source. The Mothers Day source had winds to storm- force and the dominant period was longer.
Wave Watch III places the onset stage for the new event locally Saturday 5/25 centered from 190 degrees. Inconsistent sets above average are possible 5/25 PM.
The event should be filled in by Sunday 5/26 with a peak late in the day well above average. Slow change is expected with similar surf Monday morning followed by a downward trend into Tuesday from 180-200 degrees. Small surf from this direction should hold into Wednesday.
The New Zealand source zone of 5/14-20 shifted to the eastern edge of the Hawaii swell window south of French Polynesia 5/21-24. It is expected to hold over this area into 5/26, making for a series of lower events locally from 175-185 degrees, each being a notch smaller. Comparison of Wave Watch III output points of Pago Pago and Papeete show the further east dominance of the swell swath with low, long period swell at the former and large long-period swell at the latter. This near miss to the east makes for big error bars on the local surf estimate.
The first one flared up as it crossed over 160W south of Hawaii 5/21-22 with gales to severe gales aimed highest SE of Hawaii. Long period onset from source centered near 180 degrees is expected within late Monday 5/27 to mid Tuesday 5/28. It should peak near to a notch above average early Wednesday.
Into the long range, the second flair up at 160W south of French Polynesia took place 5/23-24 with weaker winds and less northward aim of seas. This event is expected to stay on the low side of the average locally within 5/29-6/1 from 180 degrees. Hints of one more low one near background levels for 6/2-4 from the same direction.
In the north Pacific, the second reinforcement to the Aleutian low is due 5/28-29 and could make for tiny to small NNW surf locally 5/31-6/1.
East side is predicted to trend up 5/31-6/2.
Long range forecasts are subject to high uncertainty.
This collaborative forecast will resume on Tuesday, May 28.
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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