SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
315 PM HST TUE OCT 25 2016
315 PM HST TUE OCT 25 2016
HIGH SURF ADVISORY IN EFFECT FOR NORTH FACING SHORES
Surf along north facing shores will be 12 to 18 feet tonight through Wednesday morning, lowering to 10 to 14 feet Wednesday afternoon and 6 to 8 feet by Wednesday night.
Surf along west facing shores will be 5 to 8 feet tonight, lowering to 4 to 7 feet Wednesday.
Surf along east facing shores will be 2 to 4 feet through Wednesday.
Surf along south facing shores will be 2 to 4 feet through Wednesday.
Outlook through Tuesday November 01: the current long period west-northwest swell has started to arrive, and larger than expected. A high surf advisory is posted through noon Wednesday for north facing shores. This current swell will then ease into Thursday. Kauai will help block much of west-northwest swell from producing advisory conditions along west facing shores. A small north-northeast swell is expected to peak Friday, followed by a small long period northwest swell peaking this weekend. Surf along east facing shores will begin to build later in the week as strong trade winds return. A long period east swell from hurricane Seymour is expected to peak Saturday. Small southerly swells will continue to generate small surf along south facing shores through much of the period.
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
236 PM HST TUE OCT 25 2016
THIS COLLABORATIVE FORECAST WILL BE UPDATED MONDAY THROUGH FRIDAY AT
300 PM WHEN PAT CALDWELL IS AVAILABLE/
|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 OF 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)|
SURF HEIGHTS WILL VARY BETWEEN DIFFERENT BEACHES AND AT THE SAME
BEACH AT DIFFERENT BREAK AREAS.
Discussion: summary: Mix of swell from around the compass.
Detailed: Mid Tuesday on northern shores has long-period breakers above the active season, September to may, average from 300-315 degrees. This direction receives partial shadowing by Kauai on Oahu, making for gradients of surf energy locally along the west and north coasts of Oahu. Heights should remain above average on Wednesday with a downward trend.
A low pressure deepened rapidly 10/21 east of Kamchatka. Severe gales to storm-force winds grew seas over 35 feet by mid Saturday in an area about 2200 nm away. The center of low pressure moved steadily north near 165°E into the Bering Sea as it weakened 10/22-23.
The NW Hawaii NOAA buoy 51101 showed a sharp ramp up in wave energy Monday night. The pacioos/cdip Waimea buoy jumped steeply after dawn Tuesday 10/25. Since the source is remote, dispersion, or the spreading of swell trains by wave period, would allow the peak elevations to last longer locally as the dominant period gradually falls Tuesday night through Wednesday. The direction should remain 300-315 degrees. Heights should fall below average by Wednesday night, and a steady drop on Thursday.
The Pacific synoptic map is a tale of two troughs on Tuesday. The jet stream has large troughs in the eastern and western Pacific, with a blocking ridge in between over longitudes near Hawaii to the dateline. This should give a mix of NW and NNE surf as well as active trades in Hawaii.
Low pressure fills a vast area of the eastern north Pacific. Northerly winds on the west side within 140-150°W north of 30°N have aimed strong to marginal gales at targets east of Hawaii. Angular spreading should bring in shorter-period, small surf locally, picking up Thursday and holding into Saturday from 000-030 degrees.
Low pressure in western russian and the Bering Sea has placed gales in the Kamchatka corner starting late Monday, as validated by the ascat satellite. This system is much weaker and further away than the source producing the surf locally 10/25. The new source should be short-lived.
Surf from 310-325 degrees is expected to build locally Friday night, with the event peaking late Saturday. It should drop on Sunday from the same direction.
Mid Tuesday on eastern shores has breakers below the trade windswell average. Similar conditions are expected for Wednesday.
The jet trough in the eastern north Pacific and its associated surface troughs cut off the trade windswell source for Oahu starting Monday. Ascat showed a large area of gentle to moderate winds to the immediate E to NE late Monday into Tuesday. Surf should remain small through Wednesday.
Models show the low pressure areas to the NE of Hawaii lifting out as high pressure moves in 10/26-27. This should trend up the trades locally and well to the E to NE of Hawaii. Surf from windswell should build above average by late Thursday and remain elevated near to just above average through the weekend from 60-90 degrees.
Hurricane Seymour in the eastern tropical Pacific has a clear eye as viewed from satellite on Tuesday 10/25. Models show it remaining category 2 or stronger into Wednesday as it slowly tracks NNW. It is expected to weaken near 122°W Thursday into the weekend. The strongest stages of Seymour have been and are projected to be in the Oahu swell window and should make for small to moderate surf locally over the weekend.
Low, long-period swell from 80-100 degrees is modelled to pick up locally Saturday and drop on Sunday. It should be short-lived. Seymour surf should be near the average trade windswell height.
Mid Tuesday on southern shores has breakers from 180-190 degrees near the active season, March to October, average. Similar surf is possible for Wednesday.
A slow-moving, large area of gales tracked east along 45°S to the east of New Zealand 10/17-20. It had a long, wide fetch aimed well at Hawaii, though the magnitude of the surface winds was just too weak to bring surf locally above average. The event should be long-lived. It picked up late Sunday and should hold into Thursday from 170-190 degrees. It should fade out Friday.
Into the long range, sources in the mid latitudes of the southern hemisphere are reflecting the calendar as the austral spring progresses. No surf beyond tiny is expected locally from 140-210 degrees 10/31-11/3.
Models show a low pressure dropping near 950 mb near the central Aleutians 10/29. This suggests above average, long-period surf for Hawaii starting late Tuesday 11/1 and peaking 11/2 from 320-340 degrees.
Fresh trades and average windswell from 70-90 degrees is predicted for 10/31-11/3.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Friday, October 29.
This forecast was produced through the collaborative efforts of NWS and ncei. Please send suggestions to email@example.com or call the Warning Coordination Meteorologist at 808-973-5275.
Additional resources: see /in lowercase/ http://www.prh.noaa.gov/hnl/pages/marine.php.
NWS Forecaster and NCEI PAT CALDWELL
|Waimea Buoy||Kailua Buoy||Lanai Buoy||Barbers Point #2||Pauwela, Maui||Hilo Bay Buoy||Kaneohe Bay Buoy||Hanalei Kauai Buoy||Kilo Nalu||Buoy 51001||Buoy 51101||Buoy 51000||Buoy 51100||Buoy 51002||Buoy 51003||Buoy 51004|