SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SAT AUG 30 2014
400 AM HST SAT AUG 30 2014
HIGH SURF ADVISORY FOR SOUTH FACING SHORES
Surf along south facing shores will be 6 to 9 feet today and tonight, decreasing to 5 to 8 feet Sunday.
Surf along east facing shores will be 4 to 6 feet through Sunday.
Surf along west facing shores will be 3 to 6 feet today and tonight, decreasing to 2 to 4 feet Sunday.
Surf along north facing shores will be 1 to 3 feet today and tonight, decreasing to 2 feet or less Sunday.
Outlook through Friday September 5: south facing shores will continue to see advisory level surf through Sunday. South facing shores will see more wave action next week with a moderate size long period swell expected Tuesday and Wednesday. East swell persist for the next few days, producing surf below advisory level.
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 FRI AUG 29 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: south side above average through the period.
Detailed: mid Friday on southern shores has above summer average surf from 180-195 degrees with 12-17 second wave periods. A slight decline is predicted for Saturday.
A large-scale jet stream trough east of New Zealand 8/20-25 was associated with a complex pattern of surface low pressure cells and cold fronts. Combined with a strong surface high pressure over the Tasman sea, long, wide fetches dominated the region from antarctic to the tropics from New Zealand eastward to south of French Polynesia. This pattern has given way to the abundant southerly surf locally.
A low pressure near 40s, 160°W 8/21 and its associated cold front backed by gales reached to near 28°S by 8/22. This is the source for the above average surf that grew locally on Thursday 8/28 and is peaking in the morning 8/29. Buoy 51003 to the SW of Oahu 9 am HST 8/29 showed another surge in the 13-15 second bands that will clearly keep similar surf through Friday evening. Models suggest a slight downward trend for Saturday from the same broad direction 180-195 degrees.
A second low formed near the same location as the first one of 8/21, with its associated front reaching the subtropics 8/25. It should serve to keep surf elevated, with a rising trend Sunday from 180-195 degrees. It should peak on Monday and slowly decline on Tuesday as a new event slowly fills in.
The jet stream pattern shifted eastward 8/25-29 with a ridge over to east of New Zealand and a broad trough S to SE of French Polynesia. The associated surface low pressure cells got much stronger, though not as well pointed to Hawaii.
The first system tracked from near the antarctic ice sheet near 170°W 8/26 northeastward to 150°W 8/27. Storm-force winds grew seas to 30 feet. Long-period swell of 17-19 seconds from 180-190 degrees are due locally on Tuesday 9/2. It will have added energy from the second system.
A hurricane-force system formed near 170°W along the ice sheet 8/27 and followed the first system. Seas grew over 30 feet for a massive area and over 40 feet for a large area, aimed best at targets east of the Hawaii swell window. Angular spreading will deliver surf locally. Since waves of longer periods travel faster, the extra-long wave intervals of the second system should catch up to the first system, both arriving locally Tuesday 9/2.
Surf is expected to steadily build late Tuesday into Wednesday at levels above the summer average from 175-190 degrees.
Mid Friday on eastern shores has heights near to a notch above the east side average. Heights are trending up.
A long-lived area of enhanced trades near 30°N, 140°W has kept longer-period windswell of 8-10 second from 45-60 degrees locally 8/25-29. This event is expected to decline on Saturday and fade out by Sunday.
The hurricane Marie swell was not well modelled by most wave models, which brought the long-period swell in sooner and bigger than occurred. Since there are not many similar cases such as the cat 5 Marie status of of 8/24-25 from a remote area beyond 2000 nm away, the NWS forecast erred towards safety in following the majority of the wave model guidance packages.
The pacioos/cdip nearshore buoy off Pauwela, NE Maui shows an upward trend in the 14-18 second band late Friday morning 8/29 from 75-100 degrees. This episode should build locally Friday afternoon and remain about the same through Saturday. It should slowly decline Sunday into Tuesday as the direction favors 60-80 degrees.
Trades should have a slow upward trend to moderate speeds by Wednesday with locally shorter-period swell below average.
Mid Friday on northern shores has near flat conditions except for locations receiving the NE windswell. Similar surf is expected on Saturday.
A compact near gale off the northern Kuril Islands 8/27 tracked NE to the Bering Sea west of the dateline 8/29. The system was over 2400 nm away. Wave watch iii suggests 1 feet at 12 second for Monday with a dropping trend Tuesday. Low odds for tiny to small surf locally.
Into the long range, the predicted jet stream pattern does not suggest any surface low pressure cells that would be of caliber to make surf beyond tiny locally from WNW to N 9/4-6.
East side should remain below average with gentle to moderate trades.
The south side should remain above average 9/4-5 with a downward trend 9/6-7 from 170-190 degrees.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Tuesday, September 2.
This forecast was produced through the collaborative efforts of NWS and NCDDC. 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.
|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|