Swell Forecast & Schedule

Report Date: Fri. March 12, 2010
Forecast Source: NWS and NCDDC.

---

For those of you who wish to use Swellwatch on the go, we have put together a mobile site, which can be used by any Internet enabled phone.  Check out the site mobile.wetsand.com from your device, for up to date Surf, Tide, and weather information, as well as our hand written reports.

Recommended Board:

---

Surf Zone Forecast

National Weather Service- Honolulu, HI

Surf along north facing shores will remain 3 to 5 feet through Friday.

Surf along west facing shores will be 1 to 3 feet through Friday.

Surf along east facing shores will decrease to heights of 4 to 6 feet Friday.

Surf along south facing shores will increase to heights of 1 to 3 feet Friday.

Outlook through Wednesday Mar 17: a large northwest swell that will produce surf well above advisory levels on north and west facing shores is expected Sunday night through Tuesday.

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 Forecast for Oahu

NWS/NCDDC- Honolulu, HI

This collaborative forecast will be updated Monday through Friday at 300 pm when Pat Caldwell is available. When Pat Caldwell is not available, the latest collaborative forecast will remain posted for 4 days.

Surf heights will vary between different beaches and at the same beach at different break areas.

Summary: windward shores tapering down and northern shores rising late Sunday.

Detailed: mid Wednesday on northern shores has small breakers from refracting windswell. More of the same is expected on Thursday.

The zonal jet stream just south of the Aleutians has been steering surface low pressure systems eastward with about a 3 day spacing. The fast forward motion limits fetch duration and makes for below average surf conditions in Hawaii from the NW to N.

One such system this past Sunday was expected locally on Wednesday. It is barely traceable in the buoy data. It may gain slightly on Thursday into Friday from 330-360 degrees, though the windswell should continue the dominant surf producer.

The next system in the zonal jet intensified as it tracked north of Hawaii late Tuesday. The fetch aimed at Hawaii was weaker and shorter-lived than earlier predictions. Thus, the expectations for the weekend episode have been downgraded. A sub-moderate episode should build overnight Friday, peak on Saturday from 330-350 degrees, and drop into Sunday.

A storm-force system is forming on Wednesday near Japan. Models show a broad surface low pressure tracking across the breadth of the north Pacific basin. On Thursday into Friday, swell generation is expected to favor the 305-320 degree band to about the dateline. Long period forerunners from this source should build mid Sunday and peak on Monday at marginally high levels by sundown.

Late Friday into Sunday, gales to severe-gales are modelled in the 320-340 degree band as the center of low pressure passes north of Hawaii on Sunday. The head of the fetch should reach to about 800 nm away by late Saturday. The proximity ups the surf potential. Surf should climb well into the high bracket on Monday centered on 330 degrees, but spread between 305-350 degrees, and added to the rough windswell on Monday, should make for confused breakers.

Mid Wednesday on eastern shores has rough, high breakers from 50-90 degrees under strong trades. The mokapu buoy shows the dominant wave period has increased, which increases the amplification of wave height when breaking. Models show upstream and local trades weakening to fresh levels on Thursday, with a drop off in the surf to moderate to marginally high levels. The trend in wind and waves continues a drop into Saturday. Models suggest strong trades well east of the islands could keep small to moderate, short-period breakers over the weekend from 60-90 degrees.

A front is expected on Sunday. See the latest NWS state weather forecast discussion for explanation, timing, and strength. After the front, fresh to strong breezes from 30-50 degrees are expected , veering to typical trades within 50-80 degrees on Monday. Subsequently, a new windswell episode is expected, climbing back toward marginally high levels on Monday.

Mid Wednesday on southern shores has refracting windswell. More of the same is expected through the period. A short-lived, small, long-period southern hemisphere swell could pick up late Thursday from 180-200 degrees, from a source SE of New Zealand about a week ago.

Into the long range, an occluding low pressure near 150°W to the south of French Polynesia could bring in a small episode late next week from 160-180 degrees. Models suggest an average to above average spell of surf from 180-200 degrees off and on for the last 10 days of March due to storminess SE of New Zealand starting this weekend out a week.

In the northern hemisphere, high surf could hold into Tuesday from 340-360 degrees under moderate trades. Slowly dropping surf and wind are expected into Thursday when a new surf episode from NW to NNW is predicted late in the day in the moderate to near high bracket. Models suggest a cut off upper level low pressure N to NE of the islands mid next week, that would keep gentle to moderate trades locally mid to late next week.

Long range forecasts are subject to low confidence.

This collaborative forecast will resume on Friday, March 12. 

This forecast was produced through the collaborative efforts of NWS Forecaster HOAG and Pat Caldwell , Pacific/Hawaii Liaison Office, NCDDC