surf zone forecast
National Weather Service Honolulu HI
700 PM HST Sat Sep 6 2008
hiz005>011-071900-
Oahu-
700 PM HST Sat Sep 6 2008
...High surf advisory for south facing shores through Sunday...
Surf along south facing shores will slowly diminish to 4 to
6 feet with sets to 8 feet Sunday.
Surf along west facing shores will be decreasing to 2 to 4 feet
with occasional 5 feet Sunday.
Surf along north facing shores will be 1 to 3 feet through
Sunday.
Surf along east facing shores will be 2 to 4 feet through Sunday.
Outlook through Friday Sep 12:
the current south swell will slowly decline through the remainder
of the weekend. A southeast swell will begin building late Sunday...
overlapping the tail end of the current south swell. This new swell
may possibly reach advisory levels along south facing shores on
Monday and Tuesday. Small north-northwest and northeast swells will
build Monday and Tuesday.
Surf heights are forecast heights of the face or front of waves. The
surf forecast is based on the significant wave height 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 Thu Sep 4 2008
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.
Forecast swl dmnt dmnt h h hgt wind wind spd
date hgt dir pd 1/3 1/10 tend prob spd dir tend
1 PM 4 NE 9 4 6 same 11-16 E down
09/04 2 SSW 19 4 6 up
Fri 3 NNW 12 4 6 same Med 7-10 E same
09/05 4 NE 9 4 6 same Med
4 SSW 17 6 10 up Med
Sat 2 NNW 10 2 4 down low 7-10 E same
09/06 2 NE 9 2 4 down low
4 S 16 6 10 down Med
Sun 2 NE 9 2 4 same low 11-16 ENE up
09/07 4 S 14 6 8 down low
Mon 4 NNW 11 6 8 up low 11-16 ENE same
09/08 4 NE 9 4 6 up low
4 SSE 12 6 8 up Med
2 S 14 2 4 same low
Tue 3 NNW 9 4 6 down low 7-10 E down
09/09 4 NE 9 4 6 same low
4 SSE 11 6 8 same low
2 S 13 2 4 same low
Legend:
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.
Discussion:
summary...
busy surf pattern from southern and northern hemisphere sources.
Detailed...
mid Thursday on Southern Shores has inconsistent...mostly moderate
breakers. A new episode is slowly building from 185-195 degrees with
17-21 second periods.
A wide...long fetch of severe gales to storm force winds associated
with an extratropical cyclone unfolded in the southern hemisphere
last week. It passed south of New Zealand last Wednesday...then
steered to the NNE...which allowed an extended period of winds over
the same growing seas travelling towards Hawaii. This captured
fetch in the 185-195 degree band pushed to within 4000 nm of Hawaii
by Friday...with an apparent fetch of over 1000 nm.
Surf from this source is building today toward high levels. Readings
from buoys 51002 and 51003 have not shown significant size as of
Thursday morning. Models indicate the energy should ramp up this
afternoon and overnight at the buoys. Surf is expected to reach a
maximum between Friday afternoon and Saturday morning from 185-195
degrees.
The extratropical cyclone tracked east last Saturday into
Sunday...with severe gales in the 175-185 degree band. The system
steadily weakened Monday into Tuesday as it continued eastward. This
should lead to a more southerly swell direction locally on Sunday
into Monday...as the episode slowly subsides below the high mark.
A strong surface high pressure set up west of this extratropical
cyclone...delivering strong to near gale trades to French polynesia
this week. Swell from 150-170 degrees is expected locally starting
Monday with 10-13 second periods...making for moderate to near high
breakers. The episode is expected to be long-lived.
Mid Thursday on Eastern Shores has moderate breakers from 40-60
degrees. It was generated by near gales west of northern California
late last week...in combination with fresh to strong trades in a
region about 1000 to 2000 nm away from Hawaii. This episode is
expected to stay the same on Friday...drop over the weekend...then
receive a reinforcement with similar breakers for Monday into mid
week.
Trades are slowly weakening today with sea breezes establishing on
leeward areas. Light trades should be the rule into Saturday with
land and sea breezes for most coasts. Moderate trades should return
on Sunday...dropping again on Tuesday.
Mid Thursday on northern shores has tiny to small breakers for zones
facing 40 degrees from the source described above. A new episode
from 315-330 degrees is due later today.
A weak low pressure passed the dateline on Monday and north of
Hawaii on Tuesday with near gales in a region over 1500 nm out. Buoy
51001 is receiving 12-13 second period swell from this source
Thursday morning...suggesting a local rise before Sundown. This
episode should produce small surf on Friday from 315-330
degrees...dropping to tiny to small levels for Saturday from 330-360
degrees.
A new low pressure developed south of the Aleutians near the
dateline on Wednesday and has been steer toward Hawaii. Models show
the fetch of strong to near gale winds reaching to within about 1000
nm NNW of Hawaii on Friday. This should provide an upper-end small
episode locally building Monday from 330-345 degrees...peaking
Monday night...and dropping into Tuesday.
Into the long range...another low pressure is modelled to track just
south of the Aleutians north of Hawaii on Monday...with gales that
could make for more small NNW surf late next week. This weather
pattern should drop the trades mid week...with moderate trades by
the weekend.
In the southern hemisphere...the jet stream is zonal with strong
systems hugging the antarctic ice sheet. Small...long-period swell
from 180-200 degrees should pass through the islands due to angular
spreading mid week into the following week. The strong trades in the
southern hemisphere are modelled to continue...although not as
strong as this week. Small to moderate breakers from se to SSE are
possible mid next week out about a week. Long range estimates are
subject to major revisions. The next collaborative forecast will be
issued on Monday...September 8.
This forecast was produced through the collaborative efforts of
NWS and ncddc. Please send suggestions to W-hfo.Webmaster@noaa.Gov
or call the warning coordination meteorologist at 808-973-5275.
Additional resources:
see /in lowercase/ http://www.Prh.NOAA.Gov/hnl/pages/marine.Php
$$
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