surf zone forecast
National Weather Service Honolulu HI
900 am HST Tue Nov 18 2008
hiz005>011-190100-
Oahu-
900 am HST Tue Nov 18 2008
...High surf advisory for east facing shores...
Surf along north facing shores will be 6 to 9 feet today subsiding
to 4 to 6 feet Wednesday.
Surf along west facing shores will be 2 feet or less through
Wednesday.
Surf along east facing shores will be 6 to 9 feet today subsiding
to 5 to 7 feet Wednesday.
Surf along south facing shores will be 2 feet or less through
Wednesday.
Outlook through Monday Nov 24:
a short period northeast swell will continue to produce large...
rough surf along east facing shores through tonight then gradually
subside on Tuesday. A moderate swell from the north northwest will
build Wednesday night and peak Thursday...with a moderate
reinforcing swell from the north northwest expected during the
weekend.
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 Mon Nov 17 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 6 NNE 10 6 8 same 22-27 NE up
11/17 9 NE 8 6 8 up
Tue 9 NE 9 8 12 same high 17-21 ENE down
11/18
Wed 8 NE 8 4 6 down Med 11-16 E down
11/19
Thu 5 NNW 14 8 10 up Med 7-10 S same
11/20 4 ENE 8 2 4 down low
2 SSW 15 2 4 up low
Fri 4 N 12 6 8 down low 7-10 vrb same
11/21 5 NW 14 8 10 up low
2 S 14 2 4 same low
Sat 7 NNW 13 12 14 same low 7-10 vrb same
11/22
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...
NE windswell dropping off mid week as longer period NNW energy
arrives.
Detailed...
mid Monday on northern shores has small to moderate...mostly
confused
breakers from 000-030 degrees with 8-11 second periods. It was
generated by fresh to strong winds north of a shearline that has
recently nosed over Oahu. The dominant swell direction should
gradually favor 30-50 degrees...which puts most locations well
behind the Kahuku shadow along the North Shore...making for a drop
in surf heights into mid week.
A new gale formed near the central Aleutians on Sunday...and is
modelled to track toward the se into the Gulf of Alaska late Monday
into Tuesday. Quikscat estimates of surface wind speeds on Sunday
and early Monday showed peak winds to 40 knots with the head of the
fetch about 1500 nm away this morning in the 335-350 degree band.
Over the next 36 hours...the fetch will be aimed at targets east of
Hawaii.
This episode is expected to slowly rise around Sundown on Wednesday
from 320-330 degrees. It should peak on Thursday morning in the
moderate category from 330-350 degrees...then drop off to small
levels by mid Friday from 330-360 degrees.
Models show a low pressure system forming near the dateline about
1500 nm NW of Oahu late Tuesday...with gales in the 320-330 degree
band forming a captured fetch through early Thursday as the center
of low pressure tracks toward Hawaii...bringing the head of the
fetch within 900 nm. Surf is expected to build Friday afternoon to
moderate levels from 320-330 degrees...and peak on Saturday morning
from 320-340 degrees at marginally high levels.
Mid Monday on Eastern Shores has high breakers for locations exposed
to 000-045 degrees...and marginally high breakers due to refraction
for select easterly-facing areas. Fresh to strong trades are likely
at a maximum today yet should remain fresh on Tuesday. The dominant
short-period swell direction should rotate toward 45 degrees on
Tuesday with rough...choppy breakers continuing. Surf should drop
off steadily on Wednesday as easterly trades also drop to moderate
levels.
Low pressure and an accompanying front to the immediate WNW to N of
the islands starting Thursday is expected to draw up southerly
winds.
See the latest NWS state weather forecast discussion for details.
High uncertainty on the local wind pattern for Friday and Saturday.
Mid Monday on Southern Shores has tiny breakers. Severe gales se of
New Zealand on 11/12-13 could give small breakers from 180-200
degrees on Thursday into Friday...with small chop from the nearby
Kona (southerly) winds.
Into the long range...no significant surf is expected from southern
hemisphere sources next week. In the northern hemisphere...moderate
to near high N swell could continue on Sunday...with hints of small
to moderate NW episodes roughly Monday and again Wednesday. Moderate
trades most days next week. Long range estimates are subject to low
confidence.
This collaborative forecast will resume on Wednesday...November 19.
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
$$
NWS forecaster and ncddc pat Caldwell
