SNN BIG PICTURE: Updated Monday 3:45am 1/24

Monday, January 24^th – Tuesday, February 1^st

Local Weather Outlook –

Trades return briefly…

Late last week, a powerful 230mph jet stream blasted straight West from the northern Ryukyu Islands over the northern subtropical latitudes to just North of Hawaii at an incredible distance of over 3,300 nautical miles. This enabled storms to track across the North Pacific and reach to within close proximity of Hawaii. Trade winds were nonexistent as a result, and a mix of light flow and afternoon sea breezes dominated each day over the past few weeks. The jet stream has since weakened and become less zonal and extensive. Consequently, trades are making a comeback and will remain in place at moderate paces of 10-20mph through Thursday. For Monday, the winds will have an ENE tilt. An approaching dissipating, subtropical storm on Tuesday will turn the winds more NE. As the storm dissipates South of the Big Island, the winds will veer ENE on Wednesday. By Thursday, a front will approach the islands and cause winds to further veer ESE and weaken. The flow will become variable on Friday with the front due North of the state. As the front washes out on Saturday, moderate E-ESE flow should briefly return. Models then rapidly deepen a Kona low WNW of Kauai, which would cause winds to clock SE-SSE on Sunday at potentially moderate levels. The strength of these winds will depend on the proximity of the Kona low. Look for winds to veer SSW-S on Monday at paces light enough for afternoon sea breezes. With the system due North, winds will likely be light and variable early Tuesday with hints of trade flow returning later in the day

Scattered clouds with isolated light windward and mauka showers will return on Tuesday. In general, mostly dry weather will persist for most areas through the week and weekend. By early next week, the Kona low could change the local weather for the worst. The trend will be for wetter conditions for Monday and Tuesday.

Surf Outlook –

North and West Shores: Smaller, but still solid, swells on the way…

Recent: The aforementioned large scale pattern late last week spelled potential for extreme surf. There were two sources that combined to generate the swell. Associated with a massive cyclonic gyre that enveloped the entire western and central North Pacific, a broad fetch of 40-55mph winds were aimed directly at Hawaii over a distance of 1,800nm. Last Tuesday. Then, a low rapidly deepened alongside the fetch. Satellite passes measured a compact area of hurricane-force winds of 60-75mph associated with the low. These extreme winds only had fair aim. As the low tracked ENE over the dateline, it also strengthened the broad fetch of winds to its South to 50-65mph. In total, the fetch persisted over a duration of roughly 72 hours, an incredible feat. By Thursday morning, satellite altimetry reported seas of 42’ to within 1,400nm of Hawaii. It likely missed even larger seas. Buoy 51101, NW of Hawaii, recorded a swell peak of 24’ at 16 seconds late Friday evening, much larger than modelled. The Waimea buoy peaked at dawn on Saturday at 16.5’ of swell at 17 seconds, the second biggest swell of the 2020 decade and surpassed only by the giant NW swell of January 16, 2021, which measured 17-18’ of swell at 18 seconds. Saturday morning opened with surf in the XXL category at 20-25’ Hawaiian scale. Top sets at Waimea in early in the morning feathered outside across, and nearly closed out, the whole length of the bay. The January 16, 2021 event had a few true closeout sets. Outer reefs that best refracted WNW swells should have had top sets in the 26-28’ range. The different directions of the two swells had a pronounced effect at Makaha. In this swell, the WNW orientation had the effect of concentrating energy more into the bowl rather than the point, with top sets nearly connecting the bowl to Meyers. Surf slowly dropped during the day to 15-22’ by the afternoon. The drop accelerated overnight, and heights on Sunday morning were down to 8-12’ and  8-10’+ later in the day.

Now/Next: Late Sunday, local buoys picked up long period forerunners of 18-20 seconds. The source was a low that emerged from central Honshu and rapidly deepened last Thursday and Friday. Satellite scatterometers measured a compact area of 55-70mph winds. The system took a suboptimal track, curving NE as it approached the dateline. Surf rose rapidly from the WNW overnight and will peak Monday morning at 8-10’. A broad fetch of 40-50mph winds held behind the low and maintained direct aim at Hawaii. This means only a gradual drop to 5-7’ early Tuesday and 3-5’ early Wednesday. Surf from a secondary wind maximum in the fetch will arrive Wednesday afternoon, resulting in a gradual increase in swell period and height. Heights should reach 4-6’+ from the WNW by late afternoon and peak overnight. Surf should be 4-6’ early Thursday and steadily drop through the day. It should be 3-5’ past midday and 2-3’ Friday morning as the next event fills in.

Next: On Monday, a low from central Honshu will deepen as it tracks West with 40-50mph winds. This source is modelled to explosively deepen and broaden on Tuesday with extreme winds to 65-80mph but take a suboptimal track NE before the dateline. This limits surf potential. Borderline extra-long period forerunners of 19-21 seconds from the WNW-NW should arrive Friday morning. Surf from this source should gradually rise from 2-3’+ in the morning to 3-5’ occ 6’ in the afternoon. It should peak on Saturday at 6-8’. Heights should drop to 4-6’+ early Sunday and 2-4’ early Sunday as the swell direction veers NW.

Next: Models depict a broad low consolidating and slowing down as it approaches the Gulf of Alaska on Wednesday. Winds on its NW periphery will increase to 40-50mph with fair aim at the islands. Proximity and fetch duration greatly limit surf potential. Short-middle period forerunners of 10-14 seconds from the North should arrive Saturday morning, and surf from this source should peak later into Sunday and Monday at 2-3’.

Finally: The next storm is predicted to develop on Friday roughly 2,000nm WNW of Hawaii. The compact low could gain winds of 50-60mph as it tracks NW prior to reaching the dateline. This swell could be reinforced by a rather strong Kona low NNW of Hawaii on Sunday. Forerunners of 16-18 seconds from the WNW-NW should arrive Monday night. Surf should steadily rise from 4-6’+ Tuesday morning to 5-7’ after lunch. Surf should peak from the NW near dusk on Tuesday at 6-8’+. Models suggest continued active storm pattern across the western Pacific for moderate to large swells well into February…

South Shores: Playful, out-of-season surf this weekend…

Recent/Now: The XXL WNW swell was large enough to wrap into select town spots. Surf peaked Saturday afternoon at 2-4’ at spots exposed to West wrap. Surf has since returned to seasonably flat, which should continue through Thursday.

Finally: A solid storm emerged from South of New Zealand last Friday with 45-55mph winds. It took a slight jog ENE later Friday. Over the weekend, winds SE of New Zealand remained widespread in the 30-40mph range. Forerunners of 18-20 seconds from the SSW should arrive Friday morning. Surf should slowly rise to 1’ occ 2’ later and peak Saturday into Sunday at 1-2’+. Surf should drop to 1-2’ on Monday and 1’ occ 2’ on Tuesday.

East Shores: Small subtropical storm swell early this week, then only distant trade surf…

Recent/Now: Last Wednesday, a subtropical storm began to develop 1,300nm ESE of Hawaii. It gained expanding winds of 30-40mph as it tracked WNW over the next two days. On Friday, it tracked straight West while weakening. Short to medium period surf from the ENE of 9-13 seconds arrived late Saturday. Surf rose to 2-3’ on Sunday, which should hold through Tuesday. Heights will gradually fall midweek to 1-2’ occ 3’ early Wednesday and 1-2’ Thursday and beyond as the groundswell fades and distant trade swell becomes the dominant source.

Finally: A small North swell will add wrap of 1-2’+ to select windward spots from late Saturday to Monday.

Tropics: Nothing for this 7-day outlook.

Surf Climatology HERE