PAT CALDWELL

Hazards

HIGH SURF ADVISORY FOR EAST FACING SHORES

Forecast

Surf along north facing shores will be 4 to 7 feet tonight, rising to 6 to 10 feet Wednesday. Surf along west facing shores will be 2 to 4 feet tonight, rising to 4 to 8 feet Wednesday. Surf along east facing shores will be 6 to 8 feet tonight, lowering to 5 to 7 feet Wednesday. Surf along south facing shores will be 1 to 3 feet through Wednesday.

Outlook

Outlook through Tuesday February 27: A long period northwest swell is expected to arrive tonight and peak on Wednesday. This swell could approach advisory level on north and west facing shores. This swell will gradually subside Thursday, but another reinforcing northwest swell will move through Thursday night and Friday before fading on Saturday. Short-period east swell will continue to produce surf near advisory levels on east facing shores tonight, before possibly dropping below advisory levels Wednesday. Another boost on Thursday will likely bring advisory level surf back to east facing shores into the weekend. 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, at the locations of the largest breakers. 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.

About Collaborative Surf

This collaborative forecast will be updated Monday through Friday at 300 PM when Pat Caldwell is available.

Collaborative Surf Table

FORECAST
DATE
SWL
HGT
DMNT
DIR
DMNT
PD
H
1/3
H
1/10
HGT
TEND

PROB
WIND
SPD
WIND
DIR
SPD
TEND
1PM
02/20
4NNW1468DOWN4-6VRBSAME
6ENE946SAME
WED
02/21
5WNW17812UPLOW7-10EUP
6E835DOWNLOW
THU
02/22
4WNW1468SAMELOW9-13SESAME
6E946UPLOW
FRI
02/23
4WNW1468SAMELOW11-16SESAME
8E968UPLOW
SAT
02/24
3NW1346DOWNLOW11-16SESAME
8E1079SAMELOW
1SW1724UPLOW
SUN
02/25
2NW1124DOWNLOW11-16SESAME
8E1079SAMELOW
1SW1523DOWNLOW

Collaborative Surf Table Legend

LEGEND:

SWL HGTOpen ocean swell height measured from trough to crestin feet located 20 nautical miles offshore
DMNT DIRDominant direction typically +/-10 degrees in 16 compasspoints
DMNT PDDominant period in seconds
H1/3Significant wave height in the surf zone
H1/10Average height in the highest one-tenth waves in the surfzone
HGT TENDHeight tendency of swell (valid values: UP/DOWN/SAME)
PROBProbability of occurrence (valid values: HIGH/MED/LOW)
WIND SPDOpen water wind speed measured in knots located20 nautical miles offshore
WIND DIRWind direction in 16 compass points
SPD TENDWind speed tendency (valid values: UP/DOWN/SAME)

Disclaimer

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

Collaborative Surf Discussion

DISCUSSION: SUMMARY:. Mid week peak from WNW with steady easterly windswell. DETAILED:. Mid Tuesday on has declining breakers from 315-330 degrees at levels below the active season, Sep-May, average. An increase is predicted for Wednesday. A jet stream block near the central to eastern Aleutians has kept mid latitude wave sources west of the Date Line. This is making for mostly below average surf. A low pressure gained storm-force east of Japan 2/18 with seas growing above 30 feet beyond 2000 nm away over the 300-310 degree band. The low was forced northward by the blocking ridge once near 170E. Long-period surf from this source should fill in locally overnight into Wednesday from 300-310 degrees. It should peak late Wednesday near the seasonal average. It should drop below average from 300-315 degrees Thursday as a new event fills in late in the day from the same direction. A second low was right behind the 2/18 system east of Japan. The follow-up low was more compact and weaker. It hit the sharp corner from east to north in track near the same area around 170E on 2/19. Though smaller and weaker, it was acting upon existing seas from the first system. This event should build late Thursday, peak Friday at levels below average from 300-310 degrees, and drop to small levels over the weekend from 300-320 degrees. Mid Tuesday on has breakers from 40-75 degrees at levels above the trade windswell average. A slight drop is predicted for Wednesday. A large area of surface high pressure fills the NE Pacific between Hawaii and the USA west coast. A fetch of fresh to strong trades extends from just east of Hawaii eastward to near 130W, nearly 1500 nm. This has allowed the dominant wave period to lean on the swell side of windswell. Longer wave periods allow greater size to breakers for the given wave heights. See the latest NWS State Forecast Discussion regarding the local winds and skies. Oahu is modelled to be near a pivot point with stronger winds to the east and lighter winds to the west. Stay tuned to the freshest forecasts. Wave-wise, the long fetch of fresh to strong upstream breezes ensures a long-lived, above average windswell regardless of the local winds. Heights are expected to remain above average through the period with a maximum within Friday to Sunday from 60-100 degrees. Mid Tuesday on has inconsistent, tiny to small breakers for select high refraction zones. Similar surf is likely for Wednesday. The easterly windswell should keep surf for select exposures through the period with better odds Friday to Sunday as the dominant windswell direction becomes more straight easterly. A storm-force low pressure tracked east along 60S SE of Tasmania 2/15-17. A low, long-period event is possible locally building late Friday, peaking late Saturday, and dropping Sunday from 208-220 degrees. , hints of gales SE of New Zealand within 2/23-27 that could make for small SSW events locally within the first week of March. In the northern hemisphere, the blocking ridge near the Aleutians should keep surf below average most days. Well below average surf is suggested for 2/26-28. Above average easterly windswell should continue 2/26-28. Long range forecasts are subject to major revisions. This collaborative forecast will resume on Friday, February 23. This forecast was produced through the collaborative efforts of NWS and NCEI. Please send suggestions to w-hfo.webmaster@noaa.gov or call the Warning Coordination Meteorologist at 808-973-5275. ADDITIONAL RESOURCES: See http://www.prh.noaa.gov/hnl/pages/marine.php

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NWS Forecaster and NCEI Pat Caldwell

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