Outlook through Tuesday December 2: the current north-northeast swell will gradually diminish on Friday, but may approach advisory levels again this weekend. This swell will then diminish early next week. A moderate northwest swell arriving early next week will produce another bump in surf heights along north and west facing shores from Monday into 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, 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.
HIGH SURF ADVISORY FOR NORTH AND EAST FACING SHORES
Surf along north facing shores will be 12 to 15 feet through Thursday. Surf along east facing shores will be 8 to 12 feet through Thursday. Surf along west facing shores will be 4 to 6 feet tonight, and 3 to 5 feet Thursday. Surf along south facing shores will be 2 feet or less through Thursday.
About Collaborative Surf
This collaborative forecast will be updated Monday through Friday at 300 pm when Pat Caldwell is available.
Collaborative Surf Discussion
SURF HEIGHTS WILL VARY BETWEEN DIFFERENT BEACHES AND AT THE SAME BEACH AT DIFFERENT BREAK AREAS. DISCUSSION: Summary: NNE swell to dominate through the period. Detailed: mid Wednesday on northern shores has near November average surf from a mix of sources. Heights are trending up. The north Pacific is in an active late fall mode with a multitude of sources making for overlapping surf episodes locally. Surf should remain near or above the seasonal average through the period. The front that pushed through Oahu on Monday had a strong surface high pressure on its heels. A large fetch of strong breezes to near gales on the E side of the high over the 320-345 degree band occurred 11/23-24 near the dateline to just NNW of Hawaii. This event peaked Tuesday and is decreasing on Wednesday 11/26. It should continue a slow decline into Thursday. Larger surf is due late Wednesday from a source to the NE of Hawaii. The jet trough associated with the front on Monday pinched off a gyre about 800 nm NNE of Hawaii. At the surface, an occluded low pressure gained strength and girth. Magnitude became stronger than predicted. Ascat satellite estimates of ocean surface winds late Monday into Tuesday showed a long, narrow fetch of storm-force winds and a wider area of gales aimed at Hawaii over the 010-025 degree band. Wave models estimated seas over 20 feet about 1000 nm away. The pacioos/cdip Pauwela, Maui buoy shows a sharp rise in wave energy Wednesday morning 11/26 from 000-025 degrees associated with this source. The near shore buoys off Oahu are trending up late morning. Surf from this nearby source is expected to build above average relative to north shore standards for locations fully exposed to this less frequent NNE swell direction. The event should peak overnight, and remain above average into Friday with a slow downward trend. A short-wave jet stream trough 11/26 north of Hawaii near 35°N is approaching the occluded gyre to the NE. This should energize the system, maintaining gales to severe gales Thursday. The combined system is modelled to slowly track NE and weaken 11/28-29. This should make for a long-lived NNE event. A reinforcement is due from 010-035 degrees locally on Saturday, building heights above average for select NNE exposures. It should peak Saturday night, then slowly decline into Monday. Heights should drop below average on Monday. Smaller sources are due this period from the NW. A fast-moving, compact, storm-force system tracked N near the dateline 11/24-25. The small size and unfavorable track relative to Hawaii means only a small episode expected locally. Energy from 320-330 degrees with 13-15 second intervals is due late Thursday into Friday, then slowly dropping into Saturday. This feature morphed on Tuesday, with the stronger cell moving north, and a weaker branch to the SE. The latter is associated with the short-wave trough in the jet north of Hawaii on 11/26. At the surface, near gales over the 330-350 degrees have nosed to about 600 nm away. This should add NNW shorter period surf building Friday and dropping Saturday. Another compact, storm-force system formed just west of the dateline near 40°N on 11/25. It is also tracking north toward the Aleutians. It has a wider area of near gales to gales from the Kamchatka corner near the western Aleutians to just west of the dateline. This should bring in a below average episode locally Sunday from 315-325 degrees, peaking Sunday night, and slowly dropping Monday. A new low pressure is forming near Tokyo on 11/26. Models show it tracking east along 35°N 11/27, with a short, though captured fetch of severe gales aimed at Hawaii. Below average energy from 280-305 degrees at 16-20 second intervals is expected to build locally mid Monday. Shadowing by Kauai lowers surf potential locally. More discussion for this event in the long range below. Mid Wednesday on eastern shores has dropping, below average breakers from windswell out of 70-90 degrees. Surf from this direction should drop on Thursday. Exposures to NNE swell as described above for north shores are trending up. Such exposures should remain elevated through the period. Short-period surf from N to NE has dropped since 11/25, though should trend up 11/26. The follow-up short-wave jet trough passing north of Hawaii 11/26 kept the large surface high pressure near the dateline. This gave way to mostly moderate winds from 20-45 degrees 11/25-26 to the immediate N to NE of Oahu, and thus below average breakers. Once that short-wave passes east of the longitude of Hawaii late 11/26, sharp upper level ridging is due to form. This is modelled to coincide with an eastward shift of the massive surface high pressure cell centered near 40°N. It should deliver the common fresh to strong trade wind events that happen often around Thanksgiving. Trades are due to steadily increase late Wednesday, and remain fresh to strong from 40-70 degrees 11/27-29. Breakers from windswell of the same direction should build above average on Thursday and remain elevated into Sunday. Models suggest trades and windswell slowly tapering down Sunday into Monday, though maintaining at least average breaker size from 40-80 degrees. Mid Wednesday on southern shores has tiny to small breakers at a few select spots. More of the same is likely for Thursday. There was a broad gale in the southern Tasman 11/17-19 that has low odds of keeping tiny to small breakers locally 11/27-28. Heights should drop to near nil from southern sources by the weekend. Into the long range, still some low pressure areas SW to SE of New Zealand that could give more tiny to small surf later next week 12/4-6 from within 180-220 degrees. In the northern hemisphere, the long-lived NNE episode should drop below average by 12/2. Models show a new occluded low pressure NE of Hawaii near 35°N, 140°W 11/30-12/2, that could bring up NNE swell again locally 12/3-5. The Tokyo low forming 11/26 is modelled to hit a block in the jet stream near the dateline on 11/28, with an abrupt track directional change to the N 11/28-29. Models show severe gales over the 300-320 degree band to within 1400 nm by late Friday, that should bring surf to near or above the November average by 12/2. This source should be short-lived. Models show that low near the central Aleutians 11/30 merging with a broader, deeper low moving off Kamchatka. This pattern is predicted to set up a large fetch of storm-force winds just south of the Aleutians 11/30-12/2 reaching to the dateline. It should bring above average NW surf locally 12/4-6. Trades are modelled to hover near the moderate mark 12/2-3 with dropping windswell from 50-90 degrees. Long range forecasts are subject to major revisions. This collaborative forecast will resume on Friday, November 28. This forecast was produced through the collaborative efforts of NWS and NCDDC. Please send suggestions to firstname.lastname@example.org or call the Warning Coordination Meteorologist at 808-973-5275. Additional resources: see /in lowercase/ http://www.prh.noaa.gov/hnl/pages/marine.php.
Collaborative Surf Table
Collaborative Surf Table 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)|
NWS AND NCDDC PAT CALDWELL