SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
300 AM HST THU APR 24 2014
300 AM HST THU APR 24 2014
Surf along east facing shores will be 4 to 7 feet through Friday.
Surf along north facing shores will be 10 to 14 feet through tonight and 8 to 12 feet Friday.
Surf along west facing shores will be 6 to 10 feet through tonight and 4 to 8 feet Friday.
Surf along south facing shores will be 2 to 3 feet through Friday.
Outlook through Wednesday April 30: a moderate northwest swell will diminish Friday and Saturday. A small northwest swell is expected from late Sunday through Monday. Fresh to strong trade winds will maintain choppy, rough surf along east-facing shores through Saturday. A small, but long-period, south swell will arrive Friday and persist through the weekend.
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 WED APR 23 2014
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 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)|
SURF HEIGHTS WILL VARY BETWEEN DIFFERENT BEACHES AND AT THE SAME
BEACH AT DIFFERENT BREAK AREAS.
Summary: surf from around the compass.
Detailed: mid Wednesday on northern shores has rising, moderate breakers from 300-320 degrees with 16-22 second periods. Heights should build within moderate to marginally high overnight and remain similar on Thursday.
The NW to central N Pacific weather pattern has been in an active cyclonic mode this week that should give a spell of average to above average spring surf 4/23-28.
A low pressure deepened rapidly Saturday east of the Kuril Islands with a NE track. The central pressure dropped to 976 mb on Sunday with severe gale to storm force winds over the 300-315 degree band. The head of the seas over 25 feet was about 2000 nm away. The jason altimeter 00Z 4/21 measured a wide swath of seas within 25-30 feet over this area.
Long period swell of 17-21 seconds arrived at NOAA buoy 51101, 270 nm WNW of Oahu, on Wednesday morning 4/23, with a significant boost around 3 am HST. The late morning pacioos/cdip nearshore buoy off Hanalei, Kauai shows the arrival of the boost around 9 am with energy levels in the 16-22 second bands that would suggest surf within moderate to high. This increase is due on Oahu in the early afternoon. Surf on Oahu from within 300-315 degrees should hold within moderate to marginally high into Thursday morning. Energy from WNW should be long-lived, slowly trending down Friday into Saturday with overlap from NW to NNW component for later on Thursday into Sunday.
The low pressure system occluded on Sunday as the low center broadened and slowly tracked NNE, settling near the Aleutians by the dateline by Monday. The highest seas were aimed at targets NE of Hawaii with a large, long fetch of marginal gales over the 310-320 degree band stretching from the far NW Aleutians to near the dateline on 3/21. The low center slowly moved east 3/21-22, maintaining gales mostly aimed NE of Hawaii and near gales at Hawaii, enough to make for a long-lived episode of surf locally at moderate or less levels.
This component from NW to NNW is expected to fill in mid Thursday, peak Friday, and slowly drop Saturday into Sunday as a new event arrives.
Another surface low pressure has deepened to storm-force conditions east of the Kuril Islands over the past 24 hours 4/22-23. It has a compact fetch of gales to storm-force winds over the 305-310 degree band. Models show it weakening as the system tracks NE, with gales over the 305-320 degree band reaching to near 1800 nm away by late Thursday. Small, long-period forerunners are due on Sunday from 305-315 degrees, with surf quasi-moderate on Monday from 305-320 degrees.
Mid Wednesday on eastern shores has choppy, moderate breakers from 60-90 degrees. Heights should increase on Thursday.
The local winds and seas reached a minimum on Wednesday morning 4/23 as one high pressure cell moved eastward to the NE of the Hawaiian islands and a new one begin filling in from the NW. It is modelled to be centered north of Hawaii on Thursday. See the latest NWS state weather forecast discussion for explanations and details of the wind trends and uncertainties.
The local and upstream fetch of fresh to strong breezes is expected to make rough conditions and raise the surf on Thursday to within moderate to marginally high, and hold about the same into Saturday from 60-90 degrees. Surf from windswell is predicted to trend down Sunday into Monday, when it reaches small levels from the same direction.
Mid Wednesday on southern shores has long-period surf from 200-220 degrees with 14-16 second intervals. Heights should slowly drop on Thursday.
A tropical cyclone tracked SE from S of noumea to off the west coast of New Zealand 4/15-17. Typically a southerly track gives poor surf potential for Hawaii since it reduces fetch length and duration. In this case, surface winds compensated to generate enough swell to give surf locally. The pacioos/cdip Lanai buoy shows the Tasman sea direction in the data for 4/23. The event should be short-lived, trending down on Thursday.
Further to the south, the jet stream S of French Polynesia amplified a large trough as progressed eastward 4/16-19, with a massive surface low pressure generating a wide area of seas over 30 feet aimed at the Americas. Angular spreading could bring in surf locally starting Friday and lasting into the weekend.
Into the long range, compact low pressure cells tracking S to SE of New Zealand 4/21-24 have low odds of making small surf mid next week 4/29-5/2 from within 180-200 degrees.
In the northern hemisphere, a low pressure cell to the N to NE of Hawaii and a high pressure cell to the NW of Hawaii 4/28-29 could bring in a small, short-period NNW to N event by late on 4/29-5/1. Windswell should increase to moderate levels from within 30-70 degrees 4/29 and hold into 4/30.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Friday, April 25.
This forecast was produced through the collaborative efforts of NWS and NCDDC. 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.
|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|