Here's a fully calibrated forecast from the best forecaster in the world, daylight second: Pat Caldwell.
DISCUSSION: SUMMARY... Short-period N swell dropping with long-period S swell rising into the weekend.
DETAILED:. Mid Friday on northern shores has breakers above the summer average from 000-030 degrees. It should hold about the same on Saturday.
A long-lived fetch of fresh to strong breezes over a large area between 40-50N to the N to NNE of Hawaii 8/4-8 was sandwiched between broad areas of high pressure to the west and low pressure to the east. The pattern remained stationary into 8/8 then weakened and moved east 8/9. There should be one more day with small breakers centered from near 10 degrees then fading on Sunday.
The remnant of typhoon Shanshan is tracked east along 40N to the west of the Kuril Islands 8/10. It is much weaker than earlier model predication had given. The fetch area towards Hawaii remains small and weak in the model packages through the weekend. There could be a slight rise from 310 degrees late Wednesday.
Mid Friday on eastern shores has breakers for N exposures aforementioned and below average trade windswell from 60-90 degrees. Low conditions should continue on Saturday.
The 8/10 morning ASCAT pass still shows some fresh speeds near Oahu though just out 60 nm or less, a short fetch. Otherwise the upstream trade windswell source regions is dominated by mostly gentle to moderate speeds. Thus the windswell is predicted to reach a minimum on Saturday.
A increase in trades over and E to ENE of Hawaii is predicted Sunday into Monday that could increase the surf a notch from trade windswell. It should remain below average.
Low, longer-period E swell are expected this period from two tropical eastern Pacific systems.
Hurricane John tracked NW to the S to W of southern Baja 8/7-9. With the medium span of the system and long travel distance over 2500 nm, only small surf is expected locally. It should fill in Sunday and hold into early next week from 80-90 degrees at levels below the trade windswell average.
Tropical storm Kristy has moved slowly N along 130W 8/8-10. The compact system is modelled to turn NW and weaken over the weekend as it remains beyond 1200 nm from Oahu. This could add small surf Tuesday into Wednesday 8/14-15 from 80-90 degrees.
Mid Friday on southern shores has breakers near to a notch below the summer average. The Hector swell has dropped to low windswell while a new long-period S swell builds.
Hurricane Hector generated well above average surf locally on 8/9 from 150-180 degrees. It was similar to the size of surf produced by Hurricane John in 1994. The latter was a category 5 system with a similar track to Hector. There was a large downwelling oceanic eddy to the SW of the Big Island as Hector passed directly over Wednesday night into early Thursday. This eddy would have had warmer sea surface temperatures that in turn could have been one of the ingredients to spur stronger ocean surface winds and a wider fetch aimed at Oahu than previously modelled 8/8 PM into the night. NOAA buoy 51004 SE of Hilo reached a maximum of 20' 8/8 while buoy 51002 south of Oahu reached 30'. This validates the more aggressive wave growth once in the Oahu swell window.
Hector continues a westward component as it gains latitude well to the WSW of Oahu 8/10. PacIOOS/CDIP Barbers Point buoy is showing low, shorter-period swell within 8-12 seconds from 180-220 degrees 8/10. This energy is predicted to fade. No more surf locally is expected for Oahu from Hector.
In the southern hemisphere a week ago, a broad area of low pressure tracked NE south of French Polynesia while a large high pressure settled east of New Zealand 8/3-5. The wide, long fetch had direct aim at Hawaii. The limiting factor was the magnitude of the winds, which stayed gale or less.
NOAA southern buoy 51002 and the PacIOOS/CDIP buoys off Barbers Point on Oahu and Kaumalapau off Lanai all show the rise in low, long-period swell 8/10. The event should be filled in by Saturday from 170-190 degrees, peak late Saturday, then slowly drop into Monday.
Background summer conditions are expected to take over by Tuesday.
Into the long range, a compact gale near 35S, 150W 8/9-10 is modelled to weaken as it moves east 8/11. It could bring surf above background levels though below the summer average within 8/17-19 from 170-185 degrees.
The tiny to small WNW event from the remnant of Shanshan is expected to linger 8/16.
Surf from 50-90 degrees is expected to remain below average 8/16-17 as the low surf from Kristy drops.
Long range forecasts are subject to major revisions.
This collaborative forecast will resume on Monday, August 13.
This forecast was produced through the collaborative efforts of NWS and NCEI. Please send suggestions to
[email protected] or call the Warning Coordination Meteorologist at 808-973-5275.
ADDITIONAL RESOURCES: See
http://www.prh.noaa.gov/hnl/pages/marine.php
NWS Forecaster and NCEI Pat Caldwell
