FZHW50 PHFO 
SRFHFO
SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
300 PM HST SAT NOV 21 2009
OAHU-
300 PM HST SAT NOV 21 2009
HIGH SURF ADVISORY NORTH FACING SHORES SUNDAY MORNING
Surf along east facing shores will be 4 to 6 feet through Sunday surf along north facing shores will be rising to 12 to 16 feet Sunday.
Surf along west facing shores will be rising to to 4 to 8 feet Sunday.
Surf along south facing shores will be 2 to 4 feet through Sunday.
Outlook through Thursday Nov 26: a large northwest swell will likely reaching advisory levels Sunday and Monday then slowly lowering into Tuesday. A larger northwest swell is expected to fill in Tuesday night, and peak late Wednesday or Wednesday night.
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, in the zone of maximum refraction. 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
300 PM HST THU NOV 19 2009
This collaborative forecast will be updated Monday through Friday at 300 pm when Pat Caldwell is available. When Pat Caldwell is not available, the latest collaborative forecast will remain posted for 4 days.
| FORECAST DATE | SWL HGT | DMNT DIR | DMNT PD | H 1/3 | H 1/10 | HGT TEND | PROB | WIND SPD | WIND DIR | SPD TEND |
| 1PM 11/19 | 5 | N | 11 | 6 | 10 | SAME | 17-21 | ENE | SAME | |
| 8 | ENE | 8 | 4 | 6 | DOWN | |||||
| 2 | SSW | 14 | 2 | 4 | SAME | |||||
| FRI 11/20 | 4 | NNE | 10 | 6 | 8 | DOWN | LOW | 17-21 | ENE | SAME |
| 8 | ENE | 8 | 4 | 6 | SAME | MED | ||||
| 2 | SSW | 13 | 2 | 4 | SAME | LOW | ||||
| SAT 11/21 | 4 | N | 13 | 6 | 8 | UP | LOW | 17-21 | E | SAME |
| 8 | E | 8 | 4 | 6 | SAME | MED | ||||
| 2 | SSW | 13 | 2 | 4 | SAME | LOW | ||||
| SUN 11/22 | 7 | NW | 18 | 14 | 18 | UP | HIGH | 17-21 | E | DOWN |
| 8 | E | 8 | 4 | 6 | DOWN | LOW | ||||
| 2 | SW | 16 | 2 | 4 | UP | LOW | ||||
| MON 11/23 | 8 | NNW | 16 | 16 | 20 | DOWN | HIGH | 11-16 | ENE | SAME |
| 6 | E | 8 | 2 | 4 | DOWN | LOW | ||||
| 2 | SW | 15 | 2 | 4 | SAME | LOW | ||||
| TUE 11/24 | 6 | NNW | 14 | 10 | 12 | DOWN | LOW | 11-16 | ENE | SAME |
| 6 | E | 8 | 2 | 4 | SAME | LOW | ||||
| 2 | SSW | 14 | 2 | 4 | SAME | LOW |
LEGEND:
| SWL HGT | OPEN OCEAN SWELL HEIGHT MEASURED FROM TROUGH TO CREST IN FEET LOCATED 20 NAUTICAL MILES OFFSHORE |
| DMNT DIR | DOMINANT DIRECTION TYPICALLY +/-10 DEGREES IN 16 COMPASS POINTS |
| DMNT PD | DOMINANT PERIOD IN SECONDS |
| H1/3 | SIGNIFICANT WAVE HEIGHT IN THE SURF ZONE |
| H1/10 | AVERAGE HEIGHT OF THE HIGHEST ONE-TENTH WAVES IN THE SURF ZONE |
| 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 LOCATED 20 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: return to seasonal high surf on north shores on Sunday.
Detailed: mid Thursday on northern shores has sub-moderate breakers from 345-020 degrees with 8-14 second periods. It was generated by near gales to gales from a system centered on about 145°W to the NNE of Hawaii on Monday into Tuesday. This episode should favor small levels on Friday from 350-020 degrees.
A reinforcement low pressure system formed on the west side of the existing low pressure area to the NNE of Hawaii also centered on about 145°W bringing more near gales to marginal gales aimed at targets east of Hawaii over the past 24 hours. Angular spreading could bring in sub-moderate breakers on Saturday from 000-030 degrees, dropping on Sunday.
The blocking ridge over the northwest Pacific shifted east enough to allow a storm- to hurricane-force system into the open waters off the northern Kuril Islands and Kamchatka over the past 48 hours. The centered tracked to the NNE during the first 24 hours starting late Tuesday, across the great circle rays relative to Hawaii, which reduces surf potential by shortening the duration. By late Wednesday, the tracked turned more NE as it broadened, allowing a longer apparent fetch. This track is similar to the system that produced the halloween weekend surf that went well into the extra-large bracket. In comparing quikscat data for that one versus this one, the previous one had a longer fetch with slightly stronger winds. None-the-less, marginal extra-large surf is expected to slowly build locally on Sunday, with forerunners filling in Saturday night from 310-325 degrees. The episode should peak Sunday night into Monday morning from 315-325 degrees. It should slowly fade below high surf levels sometime on Tuesday from 320-340 degrees.
Mid Thursday on eastern shores has moderate to marginally high breakers, especially for zones exposed to the the northerly component swell as described above. More of the same is expected into Saturday as local trades remain fresh. A downward trend in surf and wind for windward shores is expected on Sunday, except for locations exposed to refracting long-period swell from the NW. Moderate trades are expected Monday into Tuesday with small breakers from 45-90 degrees.
Mid Thursday on southern shores has tiny to small breakers, down from recent days. More of the same is expected through the period.
A storm-force low pressure system in the southern Tasman sea last weekend could bring in a small episode from 208-220 degrees this Sunday into Monday.
Into the long range, tiny to small surf for southern shores next week. Models suggest a small to moderate episode from a New Zealand system arriving around November 29, and another about 5 days later.
In the northern hemisphere, models depict a regime change with the dateline ridge giving way to a trough, and an overall southward shift to the track over most of the north Pacific, bringing systems closer to Hawaii and increasing the surf size. A severe gale is modelled to nose within 1000 nm of Hawaii by Monday, bringing extra-large surf locally on Wednesday from 320-340 degrees. Winds are expected to vary day to day as the weather systems pass north of the islands, with some days of moderate trades and others mostly light and variable.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Monday, November 23.
This forecast was produced through the collaborative efforts of NWS and NCDDC. Please send suggestions to w-hfo.webmaster@noaa.gov or call the Warning Coordination Meteorologist at 808-973-5275.
Additional resources: see (in lowercase) http://www.prh.noaa.gov/hnl/pages/marine.php.
Additional Resources:
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