Big Picture
BIG Picture updated 12pm, Sunday, November 17
Monday, November 18th – Tuesday, November 26th
Windy weather becoming light and variable by late in the week…
A dramatic change in the synoptic scale weather pattern will occur this period. From last week into the weekend, a large, potent ridge of high pressure (1037 millibars) covered the central and eastern North Pacific. This ridge will completely break down before midweek and allow for a series of storms to deepen over the central and eastern portion of the ocean basin. The western side of the North Pacific will feature transient ridging and storms confined to near the Kuril Islands. Locally, this will translate to a significant weakening of the trade wind pattern. Fresh to strong (15-30mph) ENE trades will lower to fresh paces (15-25mph) on Monday, moderate to fresh paces (10-25mph) on Tuesday, and moderate paces (10-20mph) for midweek. By Friday and Saturday, a cut-off low will approach the islands from the NW and speeds should turn light and variable. Models dig the system close enough to the islands to bring light Kona (SW-W) winds from Sunday into early next week. This type of pattern is very fickle, so the finer details of the prediction will likely change in the coming days.
Isolated to scattered light showers associated with the trade wind flow should continue into Tuesday. For midweek, the transition from trade winds to Kona winds will result in dry, pelasant weather. Things could trend a little bit rainier towards late Sunday as the aforementioned cut-off slow approaches Hawaii.
Surf Outlook –
North Shore and West Shores: Small to fun surf this week, possibly going large this weekend…
Recent/Now: Surf on Sunday was 1-3’ Hawaiian scale on significant trade wind swell wrap. The Waimea Bay buoy registered 16-18 second period forerunners of a NW swell, which was generated by a compact system with peak winds of 40-55mph aimed at Hawaii from the NW corner of the North Pacific Nov 13-14. It weakened well before it reached the dateline as it tracked eastward. Surf from this source should peak on Monday at 2-3’ and drop to 1-2’ on Tuesday as the direction turns NNW. Surf for Wednesday and Thursday should be primarily be a mix of traces from this NNW swell and declining trade wind swell wrap.
Next: Another compact system deepened SE of the Kuril Islands and similarly weakened as it approached the dateline Nov 15-16. Moderate period forerunners of 14-15 seconds from the NW should arrive overnight Wednesday. Surf should rise to 1-2’ early Thursday and peak in the afternoon at 1-2’+. It should drop to 1-2’ on Friday.
Next (Part 1): Models bomb a cyclone to hurricane-force within 600 nautical miles of the Oregan coast Nov 19. Since the system has not yet formed, it is difficult to precisely gauge swell size and timing from the core of the storm, which will be dependent on the proximity, size, and aim of the fetch. Regardless, its western flank should aim a wide fetch of 20-30mph winds at Hawaii Nov 18-19. 12-14 second period energy from the N-NNE should arrive on Thursday. Surf should rise to 2-3’ early Friday and peak in the afternoon to overnight at 2-3’+. Heights should drop to 2-3’ early Saturday as swell from the hurricane-force core of the system arrives.
Next (Part 2 – MODERATE+?): As mentioned earlier, the timing and size of swell from this part of the system is uncertain. The strongest aim will likely be towards the west, an unusual occurrence, because the cyclone should perform a loop-de-loop off the coast of Oregan with the highest winds over its northern side. Moderate to long period forerunners of 16-18 seconds from the NNE could arrive overnight Friday. Surf could rise to 2-4’ early Saturday and peak in the afternoon at 3-5’. Heights could drop to 2-3’ by early Sunday.
Finally (LARGE?): Due to the complexity of the dynamic storm track during this period, confidence for this part of the prediction is very low. A storm is modelled to cut off from the prevailing westerlies and deepen within 1,200nm of Hawaii Nov 21-22 with well-aimed winds of 35-45mph. It should slowly weaken Nov 23 and slowly nudge SE towards the islands. Proximity should significantly enhance surf potential. Moderate period forerunners of 15-16 seconds from the NW could arrive Saturday. The most recently WaveWatch III prediction is for the peak to take place late Sunday at 9’ of swell at 13 seconds, which would translate to 8-10’. Surf should drop on Monday and Tuesday.
Outlook: The highly dynamic pattern of transient ridging over the western North Pacific and cut-off lows over the central and eastern side should continue through the end of Nov. Models deepen a low to near storm-force on Nov 23 over the NW corner of the ocean. It could bring a small to moderate NW swell Nov 25-26. In the meantime, a cut-off low could linger within 1,000nm north of the islands Nov 25-26 and bring overlapping, moderate N-NNE swell Nov 25-26. The potential for additional, even more powerful cut-off lows near Hawaii should continue into December, so all eyes will on chances for significant, shorter-to-moderate period NW-NNE swell.
South Shores: Dropping trade wind swell wrap early this week with seasonable tiny surf to resume by midweek…
Recent/Now/Next: Surf on Sunday picked up a notch from Saturday to 1-2’+ from substantial trade wind swell wrap. It should be similar, maybe a notch smaller, early Monday as the trade wind swell begins to drop. Surf from the trade wind swell wrap should be 1.5’ or smaller by Tuesday for most reefs west of Diamond Head. The Barber’s Point buoy also measured tiny 16-17 second period energy from the SW on Sunday. The source of the SW swell was a storm that weakened as it approached the Tasman Sea from south of Australia Nov 8-9. It had peak winds of 40-50mph aimed somewhat well at the Tasman Sea but distance will limit surf potential. Surf from this source should peak late Sunday into Monday at 0-1.5’. It should drop on Tuesday.
Next: A compact system with a small fetch of 35-45mph winds became quasi-stationary Nov 14-15 over the central South Pacific. It could bring a tiny South swell with 0-1.5’ surf for Wednesday through Friday. Not much is noted to arrive for the weekend into early next week.
Outlook: Seasonably tiny surf from the SW-SE should resume. Models show nothing of significance through Nov 22. A more substantial system could develop a well-aimed fetch of 30-40mph winds SE of New Zealand Nov 21-23. This increases the odds for a small SSW swell (2’+) towards the end of the month. Fingers are crossed for surf to reach near the summer average Dec 1-3.
East Shores: Big trade wind swell steadily dropping through midweek with N-NNE swells taking over…
Recent/Now/Next (MODERATE TO LARGE): Surf on Sunday was 4-6’ on a large ENE trade wind swell. The waves at Makapuu were rough and breaking way outside in the middle and sometimes on the left side and washing through the left side of the bay. The reefs at Sandy Beach through Generals reached 3-5’+. Over the course of the past week, a strong, extensive trade wind fetch developed over and upstream of the islands, leading to rising swell height and period as the seas became fully developed. The 9-11 second period trade wind swell is peaking Sunday and should drop on Monday. Surf should drop to 3-5’ early Monday, 2-3’+ early Tuesday, and 1-2’+ Wednesday. It should reach a minimum of 1-2’ on Thursday. The trade wind swell will be minimal for the remainder of the period, but a series of N-NNE ground swells should keep surf going.
Finally: A 11-13 second period North swell could bring 2-3’ surf on Friday and Saturday. This could be followed by a bigger, longer period NNE swell for Saturday and Sunday with surf peaking 3-5’. Surf is likely drop to below average (less than 3’) by early next week.
Outlook: There is nothing concrete yet for additional, major N-NE swells through the end of the month but that could all change. All eyes will be on the heightened potential for surf from this angle into December. Stay tuned…
The next SNN Big Picture will be issued on Sunday, November 24.
Forecaster Jonathan Huynh
Surf Climatology HERE
