BUOY ROUNDUP
Sunday, December 21, 2025 :

Significant: Winter - Swell 8 ft @ 14 secs or greater (11+ ft faces) for 8+ hours (greater than double overhead).
Summer - Head high or better.
Advanced: Winter - Swell and period combination capable of generating faces 1.5 times overhead to double overhead (7-10 ft)
Summer - Chest to head high.
Intermediate/Utility Class: Winter - Swell and period combination generating faces at head high to 1.5 times overhead (4-7 ft).
Summer - Waist to chest high.
Impulse/Windswell: Winter - Swell and period combination generating faces up to head high (1-4 ft) or anything with a period less than 11 secs.
Summer - up to waist high swell. Also called 'Background' swell.

Surf Heights for Hawaii should be consider 'Hawaiian Scale' if period exceeds 14 secs.

PACIFIC OVERVIEW
Current Conditions
On Sunday (12/21) in North and Central CA surf was waist high on the sets and mushed and warbled and nearly chopped. It was a weak mess. Protected breaks were waist high and lined up if not somewhat closed out and clean with brisk offshore winds early. At Santa Cruz surf was flat to thigh high and warbled and mushed and not rideable. In Ventura County waves were thigh to near high on the sets and lined up with decent form and clean but pretty soft. Central Orange County had sets at waist high and lined up with decent form and clean but soft early. South Orange County's best summertime breaks had sets to thigh high and weakly reasonably lined up with good form and clean but inconsistent and very soft. North San Diego had sets at thigh high and lined up with decent form and clean. Oahu's North Shore had sets at 2-3 ft overhead and lined up with good form and clean early. The South Shore had waves at thigh to waist high and weakly lined up and soft but clean. The East Shore was getting north windswell at head high if not a little more and clean with little to no wind.

See QuikCASTs for the 5 day surf overview or read below for the detailed view.

Meteorological Overview
On Sunday (12/21) Hawaii was still getting swell originating from a weak cutoff low pressure system that tracked east from a point northwest of the Hawaiian Islands Mon-Wed (12/17) producing 18-20 ft seas aimed at the Islands then stalled north of Hawaii Wed-Fri (12/19) with 19 ft seas aimed south. California was getting only windswell generated from from weak low pressure in the Northern Gulf. A broad ill formed low is developing over the South Dateline region Sun-Tues (12/23) but not getting reasonably organized until Tues-Thurs (12/25) perhaps producing 24 ft seas aimed somewhat at Hawaii from west of the dateline. And a gale is is forecast falling southeast through the Gulf Mon (12/22) producing 18 ft seas aimed southeast at California with secondary energy forecast redeveloping Wed-Fri (12/26) producing 20-25 ft seas targeting California well. A broad system is forecast developing over the North Dateline region Sat (12/27) falling south and southeast through Mon (12/29) producing 28 ft seas initially building to 35 ft later focused primarily on Hawaii. This is a bit of an improvement over previous days model runs but still pretty weak for the time of year.

See all the details below...

SHORT- TERM FORECAST
Current marine weather and wave analysis plus forecast conditions for the next 72 hours

North Pacific

Overview
Jetstream
On Sunday (12/21) the jetstream was split just east of Japan with the northern branch tracking up over the Bering Sea then falling southeast over the East Aleutians and the southern branch falling southeast off Japan forming a trough over the dateline being fed by 140 kts winds offering limited support for gale formation there. The 2 streams reconsolidated about 900 nmiles off the US West Coast tracking inland over mostly Oregon producing weather there. Over the next 72 hours a variation on that theme is to continue with the main feature being a large split in the jet over the Central North Pacific with the previous trough on the dateline in the southern branch continuing offering minimal support for gale formation. The portion of the jet pushing into the US West Coast is to hold oscillating over North CA producing weather for that part of the state. And a new trough is forecast developing off the US West Coast on Tues (12/23) being fed by the northern branch falling south from the Bering Sea into the Eastern Gulf with winds to 150 kts offering support for gale formation. Beyond 72 hours starting Wed (12/24) more of the same is forecast with a large split in the jet off Japan with a weak trough embedded in the southern branch over the dateline and a more pronounced trough continuing off the US West Coast while slowly starting to pinch and move inland over Southern California by later Sun (12/28) supporting gale and then low pressure development and weather.

Surface Analysis
On Sunday (12/21) swell was still hitting Hawaii originating from a small local low that developed west-northwest of Hawaii (see Hawaiian Local Low below).

Over the next 72 hours a cutoff low pressure system is to develop west of the dateline (see Cutoff Dateline Low below) and a weak low is to develop in the Northern Gulf (see North Gulf Low below). And a possible gale is to develop just off California (see Possible East Gulf Gale below).

Hawaiian Local Low
Also a gale organized over the southern dateline region Sun PM (12/14) producing northwest winds at 30-35 kts and seas 21 ft at 33N 180W aimed well at Hawaii. On Mon AM (12/15) the gale fell southeast fast with northwest winds 30 kts over a small area and seas 22 ft at 29.5N 180W targeting Hawaii well. In the evening northwest winds were 25 kts over a tiny area with seas 17 ft at 27N 177W aimed southeast. On Tues AM (12/16) the gale was still producing winds at 35 kts but only in it's north quadrant aimed west with seas 20 ft at 30N 174W also aimed to the west and not targeting our forecast area. The low tracked east from there passing north of Hawaii early on Wed (12/17) producing north winds 35 kts and seas 23 ft at 31.75N 163.5W aimed south with the last of the fetch fading Fri AM (12/19) 900 nmiles north of Hawaii with sea dropping from 17 ft at 37.5N 158W aimed south. Fetch and seas were gone after that. Something to monitor.

Oahu: Residuals fading Sun (12/21) from 4.1 ft @ 11-12 secs early (4.5 ft). Dribbles Mon (12/22) fading from 3.6 ft @ 11 secs early (3.5-4.0 ft). Swell Direction: 360-010 degrees

Cutoff Dateline Low
a cutoff gale is forecast developing over the South Dateline Region Mon (12/22) starting to producing west winds in the evening at 25-30 kts targeting the Islands briefly with 17 frt seas developing at 27N 170E aimed east then dissipating. Then on Tues PM (12/23) another fetch of 30-35 kts northwest winds are to build well west of the dateline targeting the Islands with 25 ft seas at 36.5N 160E aimed southeast. On Wed AM (12/24) northwest winds are to be rotating toward the Islands at 30 kts with seas 24 ft at 33N 162.75E aimed southeast. Fetch fading in the evening from 25-30 kts and seas fading from 20 ft at 28N 165E aimed southeast. Low odds of windswell reaching the Islands.

Oahu: Rough data suggest swell arrival on Thurs (12/25) building to 3.9 ft @ 12 secs mid-day (4.5 ft). Swell fading Fri (12/26) from 4.1 ft @ 11 secs early (4.5 ft). Swell Direction: ~290 degrees

North Gulf Low
And on Sun PM (12/21) low pressure is to to develop in the Northern Gulf falling southeast towards California producing 30-35 kt northwest winds and 18 ft seas at 47N 145W aimed southeast. On Mon AM (12/22) northwest winds to be be fading from 25-30 kts with seas 19-20 ft over a small area at 46N 143W aimed southeast. The gale to fade after that. Windswell likely for CA.

North CA: Rough data suggest swell arrival on Tues (12/23) building to 5.0 ft @ 12 secs later (6.0 ft). Swell fading on Wed (12/24) from 5.6 ft @ 12 secs early (6.5 ft). Swell gone after that. Swell Direction: 303 degrees

Possible East Gulf Gale
On Tues PM (12/23) a new fetch of northwest winds at 30-35 kts is to develop in the Northern Gulf falling southeast with seas building. On Wed AM (12/24) the fetch is to be 1.000 nmiles west of San Francisco with northwest winds 35 kts and seas building from 20 ft at 38N 145W aimed southeast. In the evening a broad fetch of 30-35 kt west and northwest winds is to bloom off the entire CA coast with seas 18-20 ft from 40N 137W south to 33N 135W aimed southeast and building in coverage. On Thurs AM (12/25) northwest winds to build to 30-40 kts off North CA with seas 19-21 ft at 40N 135W filling the ocean off North CA. In the evening northwest winds to be 30-45 kts with seas 25 ft at 37.25N 139.5W aimed southeast. Fri AM (12/26) fetch is to be fading from 35 kts just off the CA-OR border with 22 ft seas fading at 40N 130W targeting North and Central CA and 18 ft seas down at 33N 138W targeting Southern CA. Fetch and seas fading after that. Something semi-real to monitor.

North Pacific Animations: Jetstream - Surface Pressure/Wind - Sea Height - Surf Height

Tropical Update
No tropical activity of interest is being monitored.

California Nearshore Forecast
(North CA is defined as the area north of the Golden Gate - Central CA from Pt Conception to the Golden Gate, and Southern CA everywhere south of Pt Conception).

Tioga Pass/Pacific Crest Trail intersection forecast: Temps - Freeze Level
More locations here (scroll down to 'Resort Snow Forecasts>Central CA or North CA Caltrans & Backcountry')

Snow Models: http://www.stormsurf.com/mdls/menu_snow.html (Scroll down for Resort specific forecasts).

South Pacific

Overview
Surface Analysis
No swell producing weather systems of interest were occurring.

Over the next 72 hours no swell producing fetch of interest is forecast.

South Pacific Animations: Jetstream - Surface Pressure/Wind - Sea Height - Surf Height

LONG-TERM FORECAST
Marine weather and forecast conditions 3-10 days into the future

North Pacific

Beyond 72 hours a broad gale is forecast developing over the dateline Fri AM (12/26) producing northeast winds at 40 kts over the Central Aleutians offering nothing yet. In the evening it is to fall south while growing in coverage producing north-northeast winds at 40 kts with seas 27 ft at 47N 180W aimed south south-southwest. On Sat AM (12/27) fetch is to fall south at 40 kts while turning more to the north with seas 29-30 ft at 43.75N 175/25W aimed south but still targeting areas a bit west of Hawaii. In the evening north winds to be 40-45 kts with seas 29 ft at 41.25N 170.5W aimed south sending possibly sideband energy towards the Islands. Fetch building Sun AM (12/28) at 50 kts over a small area from the north and northeast with seas 36 ft at 40.5N 169W aimed barely at Hawaii. In the evening north fetch falls further south at 45 kts with seas 35 ft at 38.25N 169.5W aimed south targeting Hawaii well finally. Something to monitor.

South Pacific

Beyond 72 hours no swell producing weather systems of interest are forecast.

MJO/ENSO Forecast

La Nina Is In the Ocean - But Fading in the Atmosphere
Cool Waters Dominate NINO3.4
In April 2025 weakly warm water surged east filling the Equatorial West Pacific and built into the East Equatorial Pacific. Then in late July 2025 a cool pool emerged over the East Equatorial Pacific along with a strengthened negative PDO suggesting La Nina was returning. But the SOI held generally neutral into December suggesting the atmosphere was not coupled with the ocean to support development of a wholesale La Nina. Then in Dec a long forecasted slow and steady fading of enhanced trades took over the equatorial Pacific an is to hold for the foreseeable future. Perhaps a full return to ENSO neutral is finally setting up over the equatorial Pacific.

MJO/ENSO Discussion
The Madden Julian Oscillation (MJO) is a periodic weather cycle that tracks east along the equator circumnavigating the globe. It is characterized in it's Inactive Phase by enhanced trade winds and dry weather over the part of the equator it is in control of, and in it's Active Phase by slackening if not an outright reversing trade winds while enhancing precipitation. The oscillation occurs in roughly 20-30 day cycles (Inactive for 20-30 days, then Active for 20-30 days) over any single location on the planet, though most noticeable in the Pacific. During the Active Phase in the Pacific the MJO tends to support the formation of stronger and longer lasting gales resulting in enhanced potential for the formation of swell producing storms. Prolonged and consecutive Active MJO Phases in the Pacific help support the formation of El Nino. During the Inactive Phase the jet stream tends to split resulting in high pressure and less potential for swell producing storm development. Wind anomalies in the Kelvin Wave Generation Area (KWGA) are key for understanding what Phase the MJO is in over the Pacific. The KWGA is located on the equator from 135E-170W and 5 degs north and south (or on the equator from New Guinea east to the dateline). West wind anomalies in the KWGA suggest the Active Phase of the MJO in the Pacific, and east anomalies suggests the Inactive Phase. In turn the Active Phase strengthens and the Inactive Phase weakens the jetstream, which in turn enhances or dampens storm production respectively in the Pacific.And the El Nino/La Nino cycle (collectively know as ENSO - El Nino Southern Oscillation) is a less frequent (about once every 7 years) but more impactful cycle that affects world wide weather. Specifically, strong El Nino events promote storm production in the Pacific while La Nina events suppress storm production. These therefore have a significant impact on the production of swell and surf. The paragraphs below analyze the state of the MJO and ENSO in the Pacific and provide forecasts for upcoming activity (or inactivity depending on the state and interaction of these two oscillations).

Overview: In 2019 warm equatorial waters were fading, and by August a tongue of cool water was tracking west on the equator from Ecuador over the Galapagos reaching to a point nearly south of Hawaii. A bit of a recovery tried to occur during Fall of 2019, with weak warm water building in the Nino 1.2 region, but cool water held in a pool off Peru. By April 2020 a cool pool was starting to build, forming a well defined cool tongue that evolved into La Nina, with it fully developing through July 2020. That pattern continued until late Fall 2022 when trades started fading and by early 2023 multiple Kelvin Waves were in flight with significant warming developing over the East Equatorial Pacific. La Nina was dead on 3/18/2023 with El Nino apparently developing. But it was not coupled with the atmosphere as of 7/20/2023 and never really did get well coupled. There is growing suspicion the Hunga Tonga volcano eruption (1/15/2022) muted El Ninos impact. Regardless, starting in Jan 2024 the first signs of La Nina emerged as would be expected, but never developed more than Modoki status.

Rationale: A Modoki La Nina developed in the Fall/Winter of 2024-25. It faded in Summer of 2025 then started turning toward La Nina again in Aug 2025. Considering it takes 3+ months for La Nina symptoms to appear in the atmosphere after the ocean (Nino 3.4) turns solidly to a La Nina configuration, and the ocean was just starting to make clear moves towards becoming solidly La Nina in late Aug, it seems La Nina could try to build into the jetstream/atmosphere in late Fall (Dec 2025). But the models suggest a return to ENSO neutral in Jan 2025. The other consideration is the PDO also appears to be still be in the cool phase if not cold, and it seem unlikely to change in the next 6 months. The net result is a trend towards La Nina as Fall progresses. And though the models suggest ENSO neutral to weak La Nina into Winter 2025/26, the PDO will overwhelm whatever push there is towards and ENSO neutral pattern beyond, resulting in some form of La Nina for the foreseeable future. This will result in less storm activity in the Northern Hemisphere for Fall-Winter 2025-26 with less storm days and smaller fetch area resulting in smaller and less frequent winter swells. One factor that could mitigate all of this is the fact the leading edge of the low pressure bias has already moved from 125E to 150E and west anomalies are forecast to build over the equatorial West Pacific over the coming months (Fall). If this happens, which is definitely up for debate, this could add fuel to the jetstream as it moves over the West Pacific making it strong and helping to improve support for storm development over the dateline as Winter processes. Most of the Pacific could be under La Nina, but the jetstream could be trending towards El Nino. As of right now, that is more of a minority outcome rather than a certainty.
KWGA/Equatorial Surface Wind Analysis (KWGA - Kelvin Wave Generation Area - The area 5 degrees north and south of the equator from 135E to 170W - The main area for generating Kelvin Waves)
Analysis (TAO Buoys): As of (12/20) 5 day average winds were moderate east over the far East equatorial Pacific and strong east over the Central Pacific and strong east over the dateline/KWGA. Anomalies were neutral over the East Pacific and neutral over the Central Pacific and moderate to strong east over the KWGA. (Note: These are 5 day average winds, versus realtime, so they lag what is happening today (by about 2.5 days).
2 Week Forecast (GFS Model): (12/21) Today moderate east anomalies were filling the KWGA. The forecast indicates moderate to strong east anomalies filling the KWGA through 12/29 then moderate quickly with weak west anomalies returning filling the KWGA 1/4 and beyond.

Kelvin Wave Generation Area wind monitoring model: West and East

CFSv2 3 month forecast for 850 mb winds, MJO, Rossby etc - Alternate link

Subsurface Waters Temps
Today (12/21) in the far West Pacific the 29 degree isotherm was easing east to 174E. The 28 deg isotherm line was easing east to 175W. The 24 degree isotherm was retrograding from 123W to 132W. Warm anomalies were +3 degs in the far West Pacific at depth at the thermocline (-150m) reaching east to 150W with cooler water east of there to Ecuador with a pocket at -2 degs filling the area from 120W to Ecuador (previously 150W). In all cool waters are still in control of the East Pacific though less strongly the last few days. The hi-res GODAS animation posted 12/14 reflects the change in trend too with weak cool anomalies filling the upper ocean above the thermocline (75 meters or higher) east of 175E. Down at the thermocline (-150m) cool anomalies were in control east of 135W (previously 155W) to Ecuador. Perhaps weak form of warm water Kelvin Wave is pushing east. Warm anomalies were filling the West Pacific. The GODAS animation is 1 week behind the TAO data but also is more detailed and accurately depicted since its satellite based.
Sea Level Anomalies: (12/14) Sea heights over the equatorial Pacific were negative (-0.5 cms) from Ecuador to 150W. -10 cms anomalies were embedded in that area but at 5 degs north and south of the equator near 150W but weakening much on the north side of the equator. The entire East Equatorial Pacific was in a cool pattern, but it seems that some warming is occurring. Heights were weakly above normal from 170W and points west of there. The cool pool is weakly fading over equator in the East Pacific.
Upper Ocean Heat Anomaly Histogram (12/14) indicates cool anomalies were filling the equatorial Pacific from Ecuador to 122W (previously 148W) and dramatically losing coverage. Warm anomalies were surging east to 150W (previously 158W). On 7/15 we went from ENSO neutral to some flavor of weak La Nina.

Surface Water Temps
The more warm water in the equatorial East Pacific means more storm production in the North Pacific during winter months (roughly speaking). Cold water in that area has a dampening effect. Regardless of what the atmospheric models and surface winds suggest, actual water temperatures are a ground-truth indicator of what is occurring in the ocean. All data is from blended infrared and microwave sensors.
Satellite Imagery
Hi-res Nino1.2 & 3.4 Qualitative Analysis: (12/20) The latest images depict a clear cool pool filling the equatorial Pacific from the Galapagos to 170E with embedded cooler pockets evenly spread across that area and holding in intensity. This looks like La Nina is in control. Alternate SST Anomaly (Global Mean): Warmer anomalies were limited west of the dateline with cooler waters east of there to Ecuador.
Hi-res 7 day Trend (12/20): Temps were warming from the Galapagos to 120W suggesting fading east anomalies there. Temp were steady elsewhere.
Nino1.2 Daily CDAS Index Temps: (12/21) (The official OISST temps are 'corrected' to the most recent 30 year base period where this data is less aggressively corrected). Today's temps were rising at -1.047 up from -1.453 the past 4 days and have been falling steadily since 12/2.
Nino 3.4 Daily CDAS Index Temps: (12/21) Today's temps were steady at -1.183 falling from -0.922 (12/7), rising since 11/26.
Weekly OISST Anomalies were falling at -0.7 (week of 12/10). Previously temps were -0.5 (12/3),. -0.6 (11/26), -0.8 (11/19), -0.7 (11/5 & 11/12), -0.6 (10/15, 10/22 & 10/29), -0.3 (10/8), -0.5 (9/24 & 10/1), -0.4 (9/17), -0.5 (9/10), -0.3 (9/3), -0.4 (8/20 & 8/27).
Monthly Data is -0.69 Nov, -0.50 Oct, -0.47 Sept, -0.36 Aug, -0.14 July -0.06 June, -0.13 May, -0.14 April, +0.01 March, -0.43 Feb, -0.73 Jan.
3 Month ONI (relative centered) 3 month period is -0.85 SON, -0.76 (ASO). -0.63 (JAS), -0.47 (JJA), -0.43 (MJJ), -0.49 AMJ, -0.52 (MAM), -0.67 (FMA), -0.89 (JFM), -1.12 (DJF), -1.07 (NDJ), -0.92 (OND).

CFSV2 Forecast for Nino3.4 Sea Surface Temp (SST) Anomalies & Current SST Anomalies

SST Anomaly Projections
CFSv2 Data (Nino3.4 Region)
Previous - Temps rose unexpectedly to +0.025 in March then faded only to -0.1 in April (far less that the -0.40 forecast) then steady at 0.00 in May-June. Temps started falling in mid-July down to -0.3 in Aug, -0.45 Sept and -0.40 in Oct.
Forecast (12/21) - Sea Surface Temp Anomalies for Nov did NOT fall nearly as hard as previously forecast (forecast was -0.95 but actual was -0.7) and then did not fall in Dec (forecast at -7.0 actual was -0.6). Temps are forecast rising from here forward -0.60 Jan, then neutral (0.0) in Mar 2026 and building after that. The PDF Corrected forecast effectively suggests the same. It looks like we're in a weak Modoki La Nina for the Fall of '25 at worst, then turning neutral before reaching Winter proper.
IRI Consensus Plume: The Nov 19, 2025 Plume (all models) depicts temps are at -0.649. Previous projections were -0.633 and -0.623. Temps to rise to -0.533 in DJF and 0.084 in AMJ. The Dynamic model suggest temps rising to -0.529 DJF and +0.543 at the end of the model run. The Statistic model suggests temps rising to -0.538 up to -0.082 at the end of the model run. In other words, We are just barely at weak La Nina today but back to neutral in January and forecast rising slowly from there indicating ENSO Neutral this Fall and Winter.
See chart here - link.

Atmospheric Coupling (Indicating the presence of El Nino in the atmosphere driven by the ocean):
Southern Oscillation Index (SOI) (negative is good, positive bad - all but the Daily Index was a lagging indicator):
Today (12/21) the Daily Index was rising at 13.96 abut had been negative since 11/28, positive at 31.56 a month earlier on 11/19.
The 30 day average was falling some at -0.62 peaking at 17.97 on 11/23, and had been rising steadily from +17.51 a month ago.
The 90 day average was rising at +7.51 and in weak La Nina territory rising from +9.41 a month ago peaking at +9.60 11/23.

Pacific Decadal Oscillation (Negative is bad, Positive is good)
Past Recent History: The PDO theoretically turned from a warm (positive) trend in Spring of '98 and has cool (negative) mostly since then other than turning weakly positive March 2014-June 2017. It went hard negative in 10/2021-10/2023 driven by a 3 year La Nina conditions (down to -3.13). It started rising (but still negative) 11/2023-2/2024 driven by a strong El Nino, but not enough to even get it to break positive ground (best reading at -1.33 on 2/24). It then started falling in March 2024 down to -3.54 Sept (the lowest since April 1859) and -3.81 (Oct) the lowest ever reported. But in Nov the index final rose some to -3.24 and -2.08 in Dec 2024 and -1.32 in Jan 2025.
Current Situation: The index was steady at -1.67 Nov, -2.40 Oct, -2.38 Sept (and inline with average readings since Nov 2021), -3.18 Aug after falling hard in July at -4.0 (the lowest ever), -2.51 June, -1.71 May, -1.18 April, -1.12 March and -1.45 Feb 2025. Looking at the long term record, it seems likely we are stable and still in the Cool Phase of the PDO (La Nina 'like') since 5/1998 with no sign of moving to the positive/warm phase (El Nino 'like') of any meaningful duration yet. We need at least 3 months of -1.2 or higher values before one could guess that maybe the cool phase is weakening.

See imagery in the ENSO Powertool 

Local Interest
Stormsurf Video Surf Forecast for this week. See it Here
For automatic notification of forecast updates, subscribe to the Stormsurf001 YouTube channel - just click the 'Subscribe' button below the video.

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ESPN Sports Center 'Ride of a Lifetime' - The backstory of Alo Slebir's possible 100+ ft wave at Mevericks - https://www.youtube.com/watch?v=luQSYf5sKjQ

NBC News - Climate Change and Surfing: https://www.nbcnews.com/mach/science/climate-change-good-surfing-other-sports-not-so-much-ncna1017131

Mavericks & Stormsurf on HBO Sports with Bryant Gumbel https://www.youtube.com/watch?v=luQSYf5sKjQ

Pieces Featuring Stormsurf:
http://www.bloomberg.com/video/how-to-predict-the-best-surfing-waves-EsNiR~0xR5yXGOlOq2MqfA.html
http://www.cbsnews.com/videos/surfs-up-for-mavericks-invitational-in-calif/

Time Zone Converter By popular demand we've built and easy to use time convert that transposes GMT time to whatever time zone you are located. It's ion left hand column on every page on the site near the link to the swell calculator.

Surf Height-Swell Height Correlation Table