Outlook through Friday November 28: a north-northwest swell arriving tonight will slowly build and produce low end advisory level surf Sunday night into Tuesday. The swell will diminish Tuesday night into Wednesday. East shore surf will decline on Sunday as winds diminish. Trade winds will then restrengthen Monday and Tuesday behind a front, leading to rough surf again along east facing shores. A north to north-northeast swell may arrive late Wednesday night then gradually diminish into the weekend. It may generate low end advisory level surf upon its arrival into Thursday afternoon. 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.
No high surf advisory or warnings.
Surf along north facing shores will be 5 to 8 feet through tonight then increase to 8 to 12 feet Sunday. Surf along west facing shores will be 3 to 5 feet through tonight, then increase to 5 to 8 feet Sunday. Surf along east facing shores will be 3 to 5 feet this afternoon then lower to 2 to 3 feet Sunday. Surf along south facing shores will be 1 to 2 feet through Sunday.
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: trending up Sunday into Monday for north shores. Detailed: mid Friday on northern shores has breakers from 305-320 degrees at 12-14 second intervals. Similar surf is predicted for Saturday. An upper level gyre centered over the Aleutians 11/15-21 set up a zonal jet stream across the NW to central N Pacific. At the surface, a series of low pressures tracked rapidly east. The weaker magnitude of the systems and the fast tracks have led to below seasonal average surf in Hawaii starting 11/19. The second surface low pressure cell in the series produced the surf of 11/21 locally. It was strongest west of the dateline 2000 nm away 11/16-17. Noaa buoy 51101 WNW of Kauai in the morning 11/21 shows a downward trend in the 13-15 second energy. This event is expected to lower overnight. A reinforcement is predicted for Saturday. The third low pressure in the series formed closer to the dateline on 11/18 and tracked rapidly NE. Highest seas aimed at targets NE of Hawaii. Wave models suggest those swell trains were close enough in direction for angular spreading to add surf locally on Saturday 11/22 from 315-330 degrees. Odds are low. This pattern is a good reminder of limitations in long range forecasts, which suggested in the roughly 10-day-out forecast early last week that this weather system near the dateline 11/18-19 would be of winter caliber and produce well above average surf around 11/22. The primary surface low pressure area associated with the upper level gyre over the Aleutians this week set up a large fetch centered over the dateline starting 11/20 north of 38°N. The winds were magnitude deficit, mostly of near to marginal gales and seas around 20 feet, which aimed better NE of Hawaii. The proximity and width of the fetch up the odds for surf in Hawaii. The pattern is expected to hold into Saturday then weaken. Surf from this source about 1300 nm away 11/20-21 should build locally Sunday morning from 320-340 degrees to levels near the November average. This episode should be long-lived, though a closer source is modelled to overlap. Model show the jet stream amplifying a trough near the dateline Saturday with a steady eastward progression. At the surface, a strong surface high pressure is modelled to follow a surface low and front, with strong to near gale winds stretching towards Hawaii to within a 500 nm by late Sunday. This should produce short- to moderate-period surf from within 320-350 degrees building mid Monday. Combined with the surf starting 11/23, heights are expected to build above average on Monday. See the latest NWS state forecast discussion regarding the arrival time and strength of a front due on Monday. Following the front, chop from 350-030 degrees is expected to build. Surf is expected to remain above average on Tuesday from within 320-010 degrees, then drop off steadily Tuesday evening into Wednesday to levels below average. Mid Friday on eastern shores has breakers near the trade windswell average. Heights are expected to lower a notch on Saturday. The recent windswell episode had the east-west axis of the surface high pressure cell fairly close to Hawaii, so the fetch of trades to the E to ENE was narrow. This kept breakers lower than one would expected given the local wind speeds. Fresh to strong breezes continue east of Hawaii 11/21 and are modelled to retreat eastward. This should allow near to below average windswell to stick around Saturday into Sunday. Surface high pressure is modelled to build north of the state Tuesday with fresh trades over a wide area to the NE. Windswell should steadily climb on Tuesday to near average levels, and build above average by Wednesday. The direction should veer on the compass along with the wind. Mid Friday on southern shores has near nil conditions except for small sets at a few select spots. More of the same is expected on Saturday. Surface low pressures have been active in the mid latitude zone for longitudes between Tasmania to E of New Zealand 11/15-21, though of size and magnitude too low to produce summery southerly surf. The pacioos/cdip buoy off samoa 11/21 should a minor increase in southerly swell. It can be traced to a compact area of gales and larger area of near gales SE of New Zealand 11/15-17. This could inch the surf up locally from 180-200 degrees 11/25, lasting a few days for top spots on the inconsistent sets. In the northern hemisphere, shorter period, well below average, NNW to NNE surf is predicted for 11/27. Models show a slow-moving surface low forming in the far NW Pacific 11/23 and a fast-moving system near 160°E, 40°N 11/24. Below average NW surf from these sources are possible roughly 11/29. Breakers from windswell out of 50-90 degrees should remain above average 11/27-28. Long range forecasts are subject to low confidence. This collaborative forecast will resume on Monday, November 24. 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 FORECASTER AND NCDDC PAT CALDWELL