HIGH SURF WARNING IN EFFECT FOR NORTH AND WEST FACING
Surf along north facing shores will be 25 to 35 feet this morning, decreasing to 20 to 30 feet during the afternoon. Surf will decrease to 15 to 20 feet by Friday morning, then decrease to 10 to 15 feet Friday afternoon.
Surf along west facing shores will be 17 to 25 feet this morning, decreasing to 14 to 20 feet during the afternoon. Surf will decrease to 10 to 14 feet by Friday morning, then decrease to 7 to 10 feet Friday afternoon.
Surf along east facing shores will be 3 to 5 feet today, with higher sets in areas exposed to the north-northwest swell. Surf will decrease to 2 to 4 feet on Friday.
Surf along south facing shores will be 2 feet or less through Friday.
Outlook through Thursday February 18: the large northwest swell will continue to decrease, dropping below advisory levels Friday night. A smaller northwest swell is expected to produce surf above advisory levels on Sunday and Sunday night, then gradually decline on Monday.
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.
About Collaborative Surf
THIS COLLABORATIVE FORECAST WILL BE UPDATED MONDAY THROUGH FRIDAY AT
300 PM WHEN PAT CALDWELL IS AVAILABLE/
Collaborative Surf Table
Collaborative Surf Table Legend
|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.
Collaborative Surf Discussion
Discussion: summary: Winter caliber NNW surf to trend down Thursday to into the weekend.
Detailed: Mid Wednesday on northern shores has rising, long-period swell of 14-22 seconds from 320-340 degrees. Heights are extra- large, meaning high enough for breakers on outer reefs. Heights should climb to giant levels, defined as peak wave face heights surpassing 40 feet on the higher, less frequent sets in zones of high refraction on outer reefs. Near shore heights are lower. Heights should remain near the giant level into Thursday from a similar direction.
A low pressure occluded on 2/8 just east of the dateline near 45°N. The broad surface low pressure covered a vast area and set up a long, wide fetch of severe-gale to hurricane-force winds nosing to near 38°N north of Hawaii. The center of the low pressure moved slowly eastward with a slow weakening trend into 2/10 as wind magnitude subsided to gales to severe gales by 2/10. For all the period, highest seas were aimed at targets NE of Hawaii. The low pressure system is expected to weaken and move out of the Hawaii swell window late Wednesday.
The jason satellite tracked over the seas and swell approaching Hawaii at 06Z 2/10, or 8 pm HST Tuesday night. It showed the onset portion of the episode with wave heights well lower than predicted by the Wave Watch III, ww3, model.
Nw Hawaii NOAA buoys 51001 and 51101 showed a slow increase in the long period wave energy Tuesday night into early Wednesday, at levels well below the ww3 predictions. Clearly the onset of the event was lower than expected. However, the wave generation source was large and much more swell is upstream to the NNW of Hawaii mid day Wednesday 2/10. It should be long-lived in winter caliber mode.
Low pressure systems that track quickly passed the longitude of Hawaii make a Christmas tree signature in the offshore swell heights with a fast rise and fall. The system of 2/7-10 was slow- moving, so higher heights should be long-lived, with more of a diamond head shape with a sharp rise, extended maximum, and a slow decline locally starting mid 2/10 through early 2/12. The direction should remain about the same from 320-340 degrees.
The tail of the fetch 2/9-10 was about 1500 nm away over the 320-330 degree band with lower-end gales. This should keep surf near the October to April seasonal average on Saturday morning, with a slow decline below average late Saturday into Sunday as a new event fills in.
A low pressure system is occluding east of the Kuril Islands near 165°E, 42°N late 2/10. Gales to storm-force winds are expected to set up a fetch over the 290-315 degree band. The center is modelled to shift slowly eastward, with the head of the fetch reaching the dateline early Friday.
The long travel distance and the shadow effect of Kauai on Oahu lower surf potential for this event. Surf is predicted to rise on Sunday from 290-315 degrees with heights above average yet below extra-large. It should peak Sunday night and slowly decline Monday from the same direction.
Mid Wednesday on eastern shores refracting energy from the NNW episode for select northerly exposures. A new windswell is modelled to pick up late Thursday.
Gentle to moderate trades are predicted to fill in locally Thursday then fade on Saturday. Breakers should remain below the trade windswell average from 70-90 degrees Friday into Saturday.
Models suggest a new fresh trade wind event for Monday 2/15, giving an upward trend to the windswell from 30-70 degrees.
Mid Wednesday on southern shores has small breakers from 180-220 degrees. Similar or lower surf is expected on Thursday.
An active austral summer pattern of extra-tropical cyclones SW and SE of New Zealand 2/1-6 has the potential to keep similar small breakers off and on through the period. Less surf is expected in the long range 2/16-19.
Into the long range for the north shores, the system described above for the 2/14-15 local swell is modelled to weaken east of the dateline as it tracks into the NE Pacific by 2/13-15. Near gales could add wave energy from 315-330 degrees late Monday into Wednesday at levels below average.
Fresh to strong trades with above average windswell is suggested in models for 2/16-17 from 60-90 degrees.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Friday, February 12.
This forecast was produced through the collaborative efforts of NWS and ncei. 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.
NWS FORECASTER AND NCEI PAT CALDWELL