A large ridge of high pressure extending from the Central to Eastern U.S. will deliver a dangerous summer heat wave through the weekend. Widespread excessive heat warnings and heat advisories already cover the Eastern two-thirds of the country. A number of record highs and overnight warm minimum temperatures are likely. Heat indices will surge past 100 degrees and approach the 110s. Heat Safety! Read More >
Surf Forecast for Oahu Issued: 07/19/2019 03:36:55 AM HST
Surf Discussion for Oahu Issued: 07/17/2019 03:00:26 PM HST
FZHW52 PHFO 
SRFHFO
SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
336 AM HST FRI JUL 19 2019
OAHU-
336 AM HST FRI JUL 19 2019
Surf along east facing shores will be 5 to 7 feet today, lowering to 4 to 6 feet Saturday.
Surf along south facing shores will be 1 to 3 feet through Saturday.
Surf along west facing shores will be 2 feet or less through Saturday.
Surf along north facing shores will be 2 feet or less through Saturday .
Outlook through Friday July 26: Choppy surf along east facing shores will remain elevated today just below advisory levels, then slowly lower over the weekend into early next week as the trades weaken. Small southwest and south-southeast swells will be possible early next week through the middle of the week. Otherwise, no significant swells are expected through the forecast period.
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.
COLLABORATIVE NEARSHORE SWELL AND WIND FORECAST FOR OAHU
NWS/NCDDC HONOLULU HI
300 PM HST WED JUL 17 2019
This collaborative forecast will be updated Monday through Friday at 300 PM when Pat Caldwell is available.
| FORECAST DATE | SWL HGT | DMNT DIR | DMNT PD | H 1/3 | H 1/10 | HGT TEND | PROB | WIND SPD | WIND DIR | SPD TEND |
| 1PM 07/17 | 4 | NNE | 8 | 2 | 4 | DOWN | 19-23 | E | UP | |
| 7 | E | 7 | 3 | 5 | UP | |||||
| 2 | SSW | 14 | 3 | 5 | DOWN | |||||
| THU 07/18 | 8 | E | 8 | 5 | 7 | UP | MED | 19-23 | E | SAME |
| 2 | S | 12 | 2 | 4 | SAME | LOW | ||||
| FRI 07/19 | 8 | E | 8 | 5 | 7 | SAME | LOW | 19-23 | E | DOWN |
| 2 | SE | 9 | 1 | 3 | SAME | LOW | ||||
| SAT 07/20 | 6 | E | 8 | 4 | 6 | DOWN | LOW | 13-19 | E | DOWN |
| 2 | SE | 9 | 1 | 3 | SAME | LOW | ||||
| SUN 07/21 | 6 | E | 8 | 4 | 6 | SAME | LOW | 13-19 | E | SAME |
| 2 | SE | 9 | 1 | 3 | SAME | LOW | ||||
| MON 07/22 | 5 | E | 8 | 3 | 5 | DOWN | LOW | 11-16 | E | DOWN |
| 1 | SW | 16 | 2 | 3 | UP | LOW |
LEGEND:
| SWL HGT | Open ocean swell height measured from trough to crestin feet located 20 nautical miles offshore |
| DMNT DIR | Dominant direction typically +/-10 degrees in 16 compasspoints |
| DMNT PD | Dominant period in seconds |
| H1/3 | Significant wave height in the surf zone |
| H1/10 | Average height in the highest one-tenth waves in the surfzone |
| 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 located20 nautical miles offshore |
| WIND DIR | Wind direction in 16 compass points |
| SPD TEND | Wind speed tendency (valid values: UP/DOWN/SAME) |
Compass & Swell Shadow Lines for Hawaii
Surf heights will vary between different beaches and at the same beach at different break areas.
DISCUSSION: SUMMARY:. East side topping the heights.
DETAILED:. Mid Wednesday on eastern shores has rising, rough breakers from 60-90 degrees at levels near the trade windswell average. Height are expected above average on Thursday.
A surface high pressure of 1032 mb near 40N, 150W Wednesday 7/17 is expected to remain nearly stationary into Friday 7/19. A wide, long fetch of fresh to strong trades has been established within 20-30N, 135-160W. ASCAT satellite 7/16-17 shows large areas with strong breezes, some of which have nosed into Oahu mid morning 7/17. The PacIOOS/CDIP Mokapu buoy off east Oahu shows a trend up in the 6-10s windswell energy.
This event is expected to grow above average Wednesday PM 7/17 and hold above average into the weekend from 70-90 degrees.
Models suggest a weakening toward moderate to fresh speeds over and E to NE of Hawaii over the weekend. Breakers from windswell are expected to trend down to near average by Monday 7/22.
Mid Wednesday on northern shores has small breakers for select NNE-facing exposures. Heights are expected to hold about the same Thursday.
The small windswell from 010-030 degrees of 7/16-17 is expected to give way to refracting energy from the easterly windswell aforementioned by Thursday. It should hold into the weekend with select locations having tiny to small breakers.
Mid Wednesday on southern shores has breakers at the seasonal average from 180-200 degrees. Heights are predicted to drop below average on Thursday.
The largest southern swell episode of the season 7/13-16 is waving goodbye 7/17. The NOAA southern buoys 51002 and 51004 late 7/16 to mid 7/17 are trending downward in the 13-15s energy toward background levels. There could be a few leftover sets within background to near average on Thursday as consistency fades.
Otherwise, a quiet pattern Downunder started for the Hawaii swell windows starting 7/10. Background surf with tiny to small breakers are expected for Friday into Monday 7/19-22 from within 140-220 degrees.
Into the long range, a series of low pressure systems in the Tasman Sea starting 7/12 are expected to continue up to 7/20. The best Hawaii surf potential was the 7/14-15 pattern hugging the east coast of Australia with a narrow fetch of severe gales. This gives odds for forerunners locally 7/22 from 208-220 degrees. This event should peak at most to average summer levels within 7/23-24.
The SE Pacific has a pair of low pressures to provide similar average or less surf. One is a subtropical gale near 25S, 135W 7/16-17. It is modelled to move SE, away from Hawaii, which lessens surf potential due to limited fetch length and duration. This shorter-period event is expected to peak locally at the same time 7/23-24. A stronger, broader low near 55S, 105W 7/16-17 has some gales to severe gales aimed at Hawaii. This should add low, long- period swell locally going into 7/25-26. For both of the SE Pacific sources, the great circle band is within 150-170 degrees, which means the swell trains are partially shadowed by the Tuamotu Islands.
Easterly windswell is expected at a minimum 7/23 with a slow increase back to average levels by 7/25.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Friday, July 19.
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 https://www.weather.gov/hfo/marine
NWS Forecaster and NCEI Pat Caldwell
Additional Resources:
Latest North Pacific Surface Analysis
Follow us on Twitter
Follow us on Facebook
Follow us on YouTube
HFO RSS Feed
