SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST WED DEC 4 2013
400 PM HST WED DEC 4 2013
Surf along north facing shores will be 3 to 5 feet this evening, increasing to 6 to 8 feet after midnight, then rising to 8 to 11 feet Thursday.
Surf along east facing shores will be 3 to 5 feet through Thursday.
Surf along west facing shores will be 1 to 3 feet this evening, increasing to 4 to 6 after midnight, then rising to 6 to 8 feet on Thursday.
Surf along south facing shores will be 1 to 3 feet through Thursday.
Outlook through Tuesday December 10: the moderate northwest swell will gradually subside Friday and Saturday. A north/northwest swell is expected to arrive late Saturday and into Sunday, peaking close to advisory levels on Monday. The moderate trade wind surf along east facing shores will gradually decrease during the next few days.
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 DEC 4 2013
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: steady surf for north shores with east side trending down and south side picking up for the weekend.
Detailed: mid Wednesday on northern shores has tiny to small breakers. A new episode is slowly filling in from 310-320 degrees. Moderate surf is expected on Thursday.
A compact surface low pressure system deepened on Sunday as it crossed the dateline near 40°N. Late Sunday into Monday had a narrow, short fetch of storm-force winds. The size and duration of the fetch was not adequate for generating longer period swell than 15 seconds. Forerunners from this stage has arrived at buoy 51101, 270 nm WNW of Oahu, in the morning 12/4 and is arriving locally in the early afternoon.
The system broadened as it weakened Monday with marginal gales over the 310-325 degree band reaching to near 1200 nm away. The jason altimeter estimated 18 feet seas in a region about 1000 nm from Hawaii on the 320 degree line near 35°N, 170°W at 12Z on Tuesday. For a wide fetch, one one expect swell at Oahu about half of that value. Since the fetch width was narrow, that takes it down to about one-third. The system continued to rapidly weaken Tuesday as it moved north.
This episode will likely peak Thursday morning from 310-325 degrees at moderate levels. Heights should drop towards small levels on Friday from 315-330 degrees as a new event arrives.
Another low pressure cell formed just west of the dateline late Monday near 35°N. Strong to near gales over a long fetch of 305-315 degrees reached to near 1000 nm away by Wednesday morning. Shorter period swell of 11-13 seconds should pick up locally Friday afternoon, bringing the heights back to the moderate bracket. Surf from this directional band should slowly drop on Saturday as more northerly component surf arrives.
The above mentioned low pressure cell is deepening on Wednesday as it tracks NNE. Models show the central pressure near 988 mb on Thursday into Friday as the system occludes and stalls near 42°N, 160°W. The early stages of the gales late Wednesday into Thursday should trend the surf up locally from 320-340 degrees Saturday afternoon into the moderate bracket.
A long fetch of gales over the 330-350 degree band stretching from the central to eastern Aleutians southward about 800 nm late Thursday into Saturday morning should make for a long-lived episode locally. Surf should peak on Sunday centered on 340 degrees within moderate to marginally high levels with only a minor drop on Monday from the same direction.
Mid Wednesday on eastern shores has moderate breakers. Similar surf is likely for Thursday.
An area of strong to near gale winds between 25-30°N about 1500 nm E to ENE of Hawaii 12/1-2 should add slightly longer wave periods to the surf on Thursday keeping moderate breakers. The closer trades between 140-155°W steadily weakened 12/2-4, that should correspond to a lowering of the deep water windswell locally. Surf should trend down locally Friday to small levels by Saturday. Heights should be at a minimum Sunday below average, with some models suggesting an upward trend starting Monday from fresh to strong trades east of Hawaii this weekend.
Mid Wednesday on southern shores has flat to small breakers from 180-200 degrees. Heights are expected to return to seasonally typically heights near flat Thursday into Saturday.
A compact gale SE of New Zealand 11/24-25 is responsible for the trace of 12-14 second swell arriving locally on 12/4. This episode should fade out on Thursday.
A complex severe-gale low pressure system tracked east along 60s to the SE of New Zealand 11/30-12/2. The head of the fetch stayed beyond 4500 nm away. Primary seas aimed SE of Hawaii. The fetch was broad and long, so significant long-period swell was generated. This should allow above seasonally normal surf heights locally, with long-period swell filling in Sunday from 180-200 degrees. Heights will likely peak on Monday.
See the latest NWS state weather forecast discussion regarding the mostly gentle wind pattern this period into early next week.
Into the long range, the south swell should hold into Tuesday 12/11 then slowly fall toward nil around Thursday 12/13. Heights should remain near flat 12/14-15.
In the northern hemisphere, the NNW episode should trend to within small to moderate by Tuesday 12/11, then to small heights 12/12. Models show a weak southern branch of the jet stream south of 40°N keeping troughs between Hawaii and the dateline with various surface low pressure cells evolving in the region. Model output of the last 48 hours has not suggested any surf beyond marginally moderate within WNW to NW locally for 12/12-14. However, with the proximity of the sources, a close eye will be kept since small errors in wind speeds within the low cells can lead to significant changes to the local surf.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Friday, December 6.
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|