Pacific Storm & Surf Forecast (Stormsurf)

Buoy 238 (Barbers Pt): Seas were 3.2 ft @ 15.4 secs with swell 1.6 ft @ 14.8 secs from 206 degrees. Water temp 77.7 (Barbers Pt), 77.4 (Pearl Harbor 233), NA (Lani 239).
Buoy 187 (Pauwela): Seas were 7.3 ft @ 8.3 secs with swell 4.9 ft @ 8.4 secs from 72 degrees. Water temp 77.4 degs
Buoy 106 (Waimea)/Buoy 202 (Hanalei): Seas were 6.6 ft @ 8.3 secs with swell 4.4 ft @ 9.0 secs from 112 degrees. Water temp 76.5 degs
Buoy 46025 (Catalina RDG): Seas were 5.6 ft @ 10.0 secs with swell 3.3 ft @ 10.2 secs from 268 degrees. Wind southeast 12-16 kts. Water temperature 62.1 degs, 60.8 (Harvest 071), 62.2 (Topanga 103), 62.1 (Long Beach 215), 62.8 (Oceanside Offshore 045), 62.6 (Del Mar 153), 62.4 (Torrey Pines Outer 100). At Harvest Buoy (071) primary swell was 5.4 ft @ 14.6 secs from 300 degrees. At E. Santa Barbara (46053) swell was 4.1 ft @ 13.5 secs from 279 degrees. At Santa Monica (028) swell was 3.3 ft @ 12.1 secs from 265 degrees. At Oceanside (045) swell was 2.7 ft @ 13.0 secs from 269 degrees. Southward at Pt Loma (191) swell was 3.5 ft @ 14.6 secs from 286 degrees. Water temperature was 62.8 degrees (Imperial Beach).
Buoy 029 (Pt Reyes): Seas were 9.7 ft @ 12.5 secs with swell 7.9 ft @ 11.9 secs from 301 degrees. Wind east at 12-16 kts (46026) and NA (1801589). Water temp NA (Bodega Bay 46013), 57.7 degs (Pt Reyes 029), 57.4 (San Francisco 46026), 56.5 (SF Bar 142), NA (1801589) and NA (Monterey Bay 46042).

PACIFIC OVERVIEW
Current Conditions
On Thursday (12/21) in North and Central CA waves were 2-3 ft overhead and clean and lined up with offshore wind and looking good, but pretty weak. Protected breaks were 1-2 ft overhead on the sets and lined up and clean but closed out. At Santa Cruz surf was head high to 1 ft overhead and lined up with good form and real clean but soft. In Southern California/Ventura waves were head high to 1 ft overhead and lined up with decent form and clean but all over the place and not feeling the bottom well. Central Orange County had sets at waist to maybe chest high and lined up but nearly trashed from south winds and chopped. South Orange County's best summertime breaks had waves at waist high and lined up and fairly clean but real soft and weak. North San Diego had waves at head high on the sets and fairly lined up and real clean with decent form but weak. Oahu's North Shore had waves at head high to maybe 1 ft overhead and cleaner and lined up but still with some warble running through it but rideable with offshore wind. The South Shore was waist to maybe chest high and clean but soft. The East Shore was getting northeast windswell at chest to shoulder high and heavily chopped from strong east-northeast trades.

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

Meteorological Overview
On Thursday (12/21) Hawaii was getting locally generated northeast windswell. California was getting swell from a local gale that fell southeast through the Eastern Gulf Mon-Tues (12/19) with seas at 24-25 ft aimed southeast. And a broader gale developed off Kamchatka tracking to the North Dateline region on Mon-Wed (12/20) producing up to 31 ft seas fading to 25 ft aimed east. The forecast is looking most interesting with a gale forecast tracking east over the dateline Thurs-Sat (12/23) producing up to 45 ft seas initially then 30+ ft seas tracking through the Central Gulf. Another smaller gale is forecast to follow on a similar track but further south starting on the dateline tracking east Sat-Mon (12/25) with seas to 47 ft aimed east. Another is to be right behind tracking from north of Hawaii to a point off Southern CA Tues-Wed (12/27) with 30 ft seas aimed east. And yet on more is to follow starting on the dateline Tues (12/26) tracking east into Fri (12/29) with seas to 55 ft aimed east. Madness. Much swell is possible.

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

Overview
Jetstream
On Thursday (12/21) the jet was consolidated pushing east-northeast off Japan with winds to 200 kts starting to form a trough over the North Dateline region offering support for gale development. East of there the jet was split with the northern branch pushing into British Columbia with winds to 120 kts not offering much and the southern branch pushing over Baja. Over the next 72 hours the North Dateline trough is to push east into the Northern Gulf on Sun (12/24) continuing to support gale development while the consolidated jet surges east with winds to 190 kts and it's leading edge poised off the North CA coast. Beyond 72 hours starting Sun (12/24) the magic starts as the jet is to be running flat east over the dateline on the 38N latitude line with winds 210 kts pushing over the dateline feeding into a developing broad trough over the Central Gulf offering great support for gale development Mon-Tues (12/26). And the last remnants of the split jet are to be moving east over California with an Atmospheric River pattern set to move onshore over Central CA on Wed (12/27). By Thurs (12/28) the jet is to recharge with 180 kts winds extending from Japan into the Gulf of Alaska with a newly developing trough there offering great support for gale development. And the leading point of the consolidated jet is to be just 300 nmiles off Pt Conception. The storm door is poised to open for California.

Surface Analysis
On Thursday (12/21) swell from a gale that developed in the Central Gulf falling southeast is hitting California (see Small Gulf Gale below).

Over the next 72 hours swell is tracking southeast from a gale that developed off the North Kuril Islands pushing to the North Dateline region (see Kuril Gale below).

And another small gale was developing just west of the dateline on Thurs AM (12/21) with 50 kt west winds and seas building from 29 ft at 44.25N 167E aimed east. In the evening the gale is to build to storm status while tracking east directly over the dateline with 50 kt west winds and seas 42 ft over a small area at 46N 178.5W aimed east. On Fri AM (12/22) the gale is to be over the Northwestern Gulf with 45-50 kt west winds and seas 45 ft at 45.75N 170W aimed east. The gale is to track east in the evening in the Central Gulf with 40-45 kt northwest winds and seas 37 ft at 45N 163W aimed east and southeast. Fetch holding Sat AM (12/23) from the northwest at 35-40 kts over the Northern Gulf with seas 33 ft over a broad area at 43.25N 156.5W. Fetch fading in the evening from 30-35 kts from the northwest in the Northeastern Gulf with seas fading from 29 ft at 44N 147W aimed southeast. Then gale to dissipate while tracking east from there. Something to monitor. Swell likely for HI and CA.

Small Gulf Gale
A small gale developed in the North Central Gulf Sun PM (12/17) generating northwest winds at 35+ kts while falling southeast with seas building. On Mon AM (12/18) the gale was falling southeast with 35 kt northwest winds and seas 20 ft over a tiny area at 45.5N 153W aimed southeast. In the evening the gale was continuing to fall southeast with 40 kt northwest winds and seas 22 ft at 47N 143W aimed southeast. On Tues AM (12/19) the gale was well off the CA-OR border with 35 kt northwest winds and seas 25 ft at 43.5N 141W aimed southeast. The gale is to race southeast in the evening with 30 kt northwest winds and seas 21 ft at 38N 135W or 750 nmiles west-northwest of San Francisco. On Wed AM (12/20) the gale is to be 300 nmiles off Pt Conception with 25-30 kt northwest winds and seas fading from 19 ft at 35N 131W aimed southeast. The gale to fade from there. Something to monitor.

North CA: Swell fading Thurs (12/21) from 5.9 ft @ 12-13 secs (7.0 ft). Swell Direction: 285 degrees

Southern CA: Expect swell arrival on Thurs AM (12/21) building to 3.5 ft @ 13-14 secs at sunrise (4.5 ft), fading some through the day. Swell fading Fri AM (12/22) from 2.1 ft @ 11-12 secs early (2.5 ft). Swell Direction: 285 degrees.

North Dateline Gale
On Mon AM (12/18) a gale was tracking east with 40 kt west winds and seas 31 ft at 48N 164.25E aimed east. In the evening west winds were 35-40 kts over a broad area with seas 31 ft at 47N 165E aimed east. On Tues AM (12/19) fetch was fading just west of the North Dateline region at 35 kts from the west with seas 29 ft at 47.25N 174.75E aimed southeast and a bit south of the Central Aleutians. In the evening fetch held at 30-35 kts from the west and seas 25 ft at 46.75N 179.5W aimed east while straddling the dateline. On Wed AM (12/20) west winds faded from 30 kts over the Northwestern Gulf with seas 22 ft at 46.5N 173.5W aimed east. Fetch was fading in the evening from 30-35 kts from the west over the Northwestern Gulf with seas fading from 21 ft at 47N 166W aimed east. Swell possible for HI and CA.

Oahu: Expect swell arrival on Fri (12/22) building to 4.1 ft @ 15 secs mid-day (6.0 ft). Swell fading on Sat (12/23) from 3.5 ft @ 13-14 secs early (4.5 ft). Swell Direction: 315 degrees

North CA: Expect swell arrival later on Sat (12/23) building to 2.8 ft @ 16 secs later (4.5 ft) but buries in local northwest windswell at 5.5 ft @ 11 secs (5.0 ft). Swell holding early Sun (12/24) at 6.0 ft @ 14-15 secs early (8.5 ft). Residuals on Mon (12/25) fading from 5.4 ft @ 13-14 secs early (7.0 ft). Swell Direction: 303 degrees

Southern CA: Expect swell arrival at exposed breaks on Sun (12/24) building to 2.5 ft @ 15-16 secs early (3.5 ft). Swell fading mon (12/25) from 2.0 ft @ 14 secs early (2.5 ft). Swell Direction: 307 degrees

Fri AM (12/22) high pressure takes hold with remnant low pressure over Southern CA and northwest winds 15-20 kts for North CA and east to northeast winds 10 kts for Central CA and south winds 10 kts for Southern CA. In the afternoon high pressure rules with northwest winds 25 kts for all of North CA and 15-20 kts for Central CA. Rain for Pt Conception southward and heavy for Southern CA early, then clearing late afternoon. No snow forecast.
Sat AM (12/23) northwest winds hold at 25 kts for all of North CA and 15-20 kts for Central CA. In the afternoon northwest winds fade at 10-15 kts for North CA And Central CA but 20 kts well offshore. No precip forecast.
Sun AM (12/24) northwest winds fade from 10 kts early for North and Central CA with a front approaching the OR-CA border. In the afternoon northwest winds are forecast at 10-15 kts for North CA and northwest 10 kts for Central CA. No precip forecast.
Mon AM (12/25) a front is to be well off the North CA coast with south winds 5-10 kts for Cape Mendocino and northwest 10 kts for the rest of North and Central CA early. In the afternoon the front starts impacting Cape Mendocino with south winds 20 kts there and south 10 kts down to Pt Arena but calm south of there to Pt Conception. No precip forecast.
Tues AM (12/26) the front holds stalled over the CA-OR border with south winds 15-20 kts for Cape Mendocino and 10 kts down to Pt Reyes and northwest 5 kts for Central CA early. In the afternoon the front starts surging south with south winds 15-20 kts for Cape Mendocino and 10 kts down to at least Big Sur if not all of Central CA. No precip forecast Rain though a front is to be building off the coast.
Wed AM (12/27) a front and south winds are to be impacting North CA with south winds 15 kts building to 35 kts over Cape Mendocino and south winds 10 kts for all of Central CA. In the afternoon the front moves inland over North CA with south winds 15 kts form Monterey Bay northward and up to 25-30 kts near Cape Mendocino. Rain developing in the afternoon for all of North CA reaching to Big Sur in the evening. Snow for the Tahoe in the evening.
Thurs AM (12/28) a light offshore flow is forecast for North CA with north to northeast winds 10-15 kts for Central CA early. In the afternoon the next front builds off the coast with east winds 5-10 kts for North CA and northwest winds 15 kts for Central CA. No precip forecast.

Total snow accumulation for the next 10 days respectively for Squaw Valley, Sugar Bowl, Kirkwood and Mammoth are projected at 2, 3, 1, and 0 inches respectively split on 12/27 and late on 12/29.

Freeze Level for Tahoe Ski Resorts: Freeze Level 8,500 ft now through 12/24 rising to 10,000 ft 12/25 and holding, then possibly falling briefly to 5,000 ft on the evening of 12/27 rising back to 10.000 beyond.

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')

Overview
Surface Analysis
No swell of interest coming from the Southern Hemisphere was hitting Hawaii or California. Summer is over.

Over the next 72 hours no swell producing weather systems of interest are forecast.

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

Beyond 72 hours another small storm is developing over the Southern Dateline region Sat PM (12/23) with 55-60 kt west winds and seas building from 41 ft at 42N 176.5E aimed east and southeast. On Sun AM (12/24) northwest winds to be 55 kts over the Western Gulf with seas building to 47 ft at 41.5N 174.5W aimed east and southeast. In the evening the storm is to fade to gael status over the Central Gulf with west winds at 45-50 kts with seas 42 ft at 40N 165.25W aimed southeast. On Mon AM (12/25) the gale is to track east over the Central Gulf with west winds 45 kts and seas 39 ft at 39.5N 155.75W aimed southeast. In the evening fetch is to be fading from 35 kts over the Northeastern Gulf with seas 32 ft at 39.25N 147.5W aimed southeast. Something to monitor.

And additional follow-on fetch is forecast right behind Mon AM (12/25) from the northwest and over the dateline at 35-40 kts with seas 26 ft at 43N 179E aimed southeast targeting Hawaii well. Northwest fetch getting somewhat more organized in the evening at 35-40 kts over the Western Gulf with seas up to 27 ft at 37N 164W aimed southeast at Hawaii. On Tues AM (12/26) fetch is to track east at 35-40 kts with seas 30 ft at 34.25N 154.75W aimed southeast. The fetch is to organize more in the evening off Central CA at 40+ kts from the northwest with seas 30 ft at 33N 146W aimed southeast. The gale is to be racing northeast Wed AM (12/27) with northwest winds 35 kts and seas 27 ft at 35N 136W aimed southeast. Fetch moving inland over Oregon in the afternoon. More to monitor.

And yet a stronger storm is forecast developing just west of the dateline Tues AM (12/26) with 40-45 kts west winds and seas building fast. In the evening northwest winds to be 55-60 kts over the dateline with seas building from 44 ft at 39.75N 179.25W aimed east and southeast. On Wed AM (12/27) 60-65 kt northwest winds are to be over the Western Gulf with seas 51 ft at 40N 168.5W aimed southeast. In the evening northwest winds to be 55 kts with seas 55 ft at 40.5N 161.75W aimed east. On Thurs AM (12/28) the storm is to be in the Central Gulf with northwest winds 55 kts and seas 53 ft at 40N 158.75W aimee southeast. The storm is to dissipate in the evening with 35+ kts west winds and seas 45 ft at 39.25N 151.5W aimed east. Impressive.

El Nino Peaking
NINO3.4 SST Anomalies Reflect a Strong El Nino
1 Kelvin Wave traversed the Pacific in Dec '22 with a 2nd in Jan-Feb and a 3rd and 4th in March-April, a 5th in May and a 6th in August. But after the last Active MJO in mid-to-late May (resulting in Kevin Wave #5), the MJO stalled. Finally the Active Phase restarted in later July Producing Kelvin Wave #6 which is erupting off Ecuador now. Another Active Phase of the MJO and 3 associated Westerly Wind Bursts developed early Oct thru later Nov producing Kelvin Waves #7 and #8 which are erupting off Ecuador now. All these Active MJO/Kevin Wave pairs are backfilling warm water off Ecuador and helping push the atmosphere deeper into El Nino. And El Nino is finally evident in the atmosphere as evidenced by the jetstream, OLR. ocean current, and wind anomalies.

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.

Rationale: A 3 year La Nina started fading in Jan 2023 and was gone by April. 6 Active MJO's produced 6 Kelvin Waves over early to mid 2023 with Kelvin Wave #7 in August building over the West Pacific and the 4th, 5th and 6th backed up off Ecuador now (10/20/23). The CFS model is predicting steady west anomalies from here forward and the leading edge of the low pressure bias moving over California now filling the Pacific. We are now under an El Nino status. We are moving into a period of enhanced storm production (starting late Sept 2023) and beyond, getting intense come late Fall and early Winter. This should result in an above normal level of swells, with swells being longer than normal duration from here forward as El Nino gets a stronger footprint on the atmosphere. The net result is a well above normal number of swells with above normal size and duration (i.e 15 significant class swells perhaps). Last year there were 0 and year before 5 or less.

KWGA/Equatorial Surface Wind Analysis (KWGA - Kelvin Wave Generation Area - The area 5 degrees north and south of the equator from 170W to 135E)
Analysis (TAO Buoys): As of (12/20) 5 day average winds were strong from the east over the East equatorial Pacific and moderate to strong east over the Central Pacific and weak west over the KWGA. Anomalies were neutral over the East equatorial Pacific and neutral over the Central Pacific and moderate west 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) West anomalies were strong over the dateline but with modest east anomalies over the western half of the KWGA. So there's a 50/50 split of east and west anomalies over the KWGA. The forecast indicates the same pattern holding to 12/28, then west anomalies shift just east of the dateline filling the East Pacific while east anomalies hold weakly filling the KWGA 12/29 through 1/3. Then West anomalies take over most of the KWGA at moderate strength through the end of the model run on 1/6. East anomalies weakened in the Indian Ocean on 12/8 and are to starting to shift east by 12/24 centered over the far West KWGA beyond. West anomalies are to start developing over over the Maritime Continent 12/22 and beyond. The Indian Ocean Dipole dissipating.

MJO/WWB/Wind Projections:
OLR Models: (12/20) The Active Phase of the MJO (wet air/cloudy skies) was barely holding over the dateline today. The statistic model indicates the Active MJO (wet air/cloudy skies) is to dissipate on day 5 of the model run over the dateline with a neutral pattern setting up for days 10 and 15 of the model run . The dynamic model depicts a far stronger Inactive signal setting up over the KWGA on days 5-15 of the model run.
Phase Diagrams - 2 week forecast (CA and GEFS): (12/21) The statistical model depicts the Active signal was weak over the East Pacific today. The forecast indicates it is to move to the Central Indian Ocean 15 days out and very weak. The dynamic model indicates the same thing but stronger at modest strength the last day of the model run.
40 day Upper Level Model (assumed to be a statistical mode and 1 week ahead of what is occurring at the surface): (12/16) This model has not updated A modest Active MJO pattern (wet air) was indicated over the KWGA today. The forecast has it holding through 12/21 then weakening on 12/26. An Inactive MJO (dry air) pattern sets up moving east over the KWGA 12/26 filling the KWGA through 1/15. The Active Phase (wet air) is to return to the KWGA on 1/15 building and filling the KWGA on the the last day of the model run on 1/25.
4 Week CFS Model (850 mb wind): (12/20) Today the Active Phase of the MJO was peaking over the KWGA with west anomalies strong over all the KWGA. The forecast has west anomalies and the Active Phase of the MJO holding strong over the KWGA through 12/28 then east anomalies starting to build into the far West KWGA 1/1 building east filling the western half of it by 1/3 and holding that position through the end of the model run on 1/17 while moderate west anomalies hold over the dateline through the end of the model run. Of note: Moderate east anomalies started building over the Indian Ocean on 9/2 holding at strong status 11/15 then moderated 11/21. They are forecast to hold at modest strength through 12/25 as the Active Phase passes over that area then returning to moderate strength through the end of the model run. That coupled with strong west anomalies in the West Pacific suggest massively falling air occurring near 120E (Maritime Continent), likely the downward branch of the Walker Circulation. The Indian Ocean Dipole is currently strong positive and building (the falling branch of the Walker Circulation). We're into a real El Nino pattern according to this model.
3 Month CFS Model (850 mb wind): (12/21) - using the 5th ensemble member - the mean of the 4 individual members which are all from the 00Z run - 1 run per day):
Today the Active Phase of the MJO was starting to peak over the KWGA with west anomalies filling the KWGA. The Active Phase is continue moving east over the KWGA filling it through 1/6 with moderate to occasionally strong west anomalies over the period. After that a weak Inactive Phase is forecast 1/7-1/14 followed by a weak Active Phase 1/15-1/30 but with west anomalies holding a moderate strength the who time. A stronger Inactive Phase is forecast 1/25-2/17 with east anomalies over the KWGA,. A stronger Active Phase to follow 2/7 through the end of the model run on 3/19 with solid west anomalies over the duration. Note: East anomalies started building at 70E (West Indian Ocean) on 9/7 and peaked 10/10-11/25 then faded some 12/11. They are to rebuild some moving forward until dissipating. This strong east and west anomaly pattern looks very much like falling air centered over the Maritime Continent (120E) associated with the downward branch of the Walker Circulation/+IOD. Outgoing Longwave Radiation (OLR) suggests cloud activity took over the KWGA weakly on 6/24 and started building in earnest then more solid starting Sept 15, It started building strongly on 10/16 and is continuing to build, strongly starting on 11/1 and is build through today. It is forecast building to strong status 1/2 at 170W and holding strength while easing slowly east to 150W at the end of the model run on 3/15. Conversely clear skies started building over the Maritime Continent in mid-May and have continued solidifying today and are forecast building into Jan 2, then fading while holding rough at 120E. This also suggests a rising air pattern associated with the upward branch of the Walker Circulation developing today on the dateline and moving east to 150W in January. The low pass filter indicates a broad low pressure bias is established over the KWGA centered at 170W with a 4th contour line (started 11/4). The fourth contour line is to dissipate on 2/11. The high pressure bias started to build over the Maritime Continent on 10/2. A second high pressure contour has faded from the model. It appears a strong El Nino is finally starting to develop in a classical sense and is to move east over the next 3 months.

Subsurface Waters Temps
TAO Array: (12/21) Today in the far West Pacific the leading edge of the 30 deg isotherm was backtracking some to 166W. The 29 degree isotherm was backtracking to 157W (previously 150W). The 28 deg isotherm line was backtracking to 142W (previously 138W). The 24 degree isotherm extended the whole way across the Pacific and deeper at 45m (25m earlier but at one point down to 65m). Anomaly wise, warm anomalies at +2 deg C start in the far West Pacific at 173E and +3 deg anomalies start at 150W and shrinking fast associated with the eastward movement of Kelvin Wave #7/8. +4 degs anomalies now start at +135W (previously 145W) pushing east in a continuous stream into Ecuador. The warm pool in the east is discharging to the surface while being backfilled by a little more warm water/Kelvin Wave #7 but no longer growing in coverage. The leading edge of Kelvin Wave #7 is starting to erupt off Ecuador per TAO from 120W and points east of there. There's about 1.5 months of warm water backed up off the Ecuadorian Coast with a stream of warm water backfilling into it per TAO. The hi-res GODAS animation posted 12/14 indicates +1-2 degs anomalies starting at 170E and over a large section of the subsurface equatorial Pacific (Kelvin Wave #7) and building while tracking east with 3 deg anomalies from 160W with embedded +4-5 deg anomalies merging with a second pool of very warm water at +4-5 degs anomalies from 135W and points east of there originating from Kelvin Waves #6, #5 and #4 erupting into Ecuador. A thin stream of +0.5 degree anomalies were falling off the Maritime Continent merging with the preexisting warm stream but cool water was building deep from 160W and points west of there. The leading edge of Kelvin Wave #7 was indicated at 100W per GODAS. A steady flow of warm water tracking east from the Maritime Continent. No cool anomalies were indicated. El Nino is developing. 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 were positive across the equatorial Pacific starting at 170W (previously 165E) at +0-5 cms extending east into Ecuador. +5 cm anomalies covered the area from 155W to 90W (Kelvin Wave #7) with +10 cm anomalies between 135W to 110W. Positive anomalies also extended north into Central America and south to Peru. This means no cool water was at depth. Per the Upper Ocean Heat Anomaly Histogram (12/14) warm water is moving east at +0.5 degs from 165W to Ecuador with a broad pocket of +1.0-2.5 deg anomalies between 156W to 92W and moving east. The leading edge of Kelvin Wave #7 per this chart is at 92W. The mature Phase of El Nino has started with cooler water developing over the West Pacific and warm water building in the east and pushing east with a new Kelvin Wave in flight. But the demise of the warm pool in the west signals an eventual turn to La Nina (sometime next year).

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 strong warm stream from Ecuador uniformly covering the area on the equator from Ecuador to the dateline. Temps are building some from 90W to 135W but have faded some between 140W to the dateline. Pockets of stronger warming were again showing between the Galapagos and 120W. Heat also extends north up to Southern Baja and south down into North Chile. There is a very clear El Nino signal with the classic El Nino triangle in-place and building towards a strong status.
Hi-res 7 day Trend (12/20): A generalized warming trend is on the equator between the Galapagos out to 150W and building solidly along the coast of Peru and Chile. In general a warming trend has been well entrenched over the East Pacific since Nov 1 2022 with no cooling waters over the equatorial East Pacific since 12/15.
Hi-res Overview: (12/20) Warmer than normal waters are filling the Equatorial Pacific from Ecuador to the dateline and strongest from 90W to 130W. The classic El Nino tongue of warm water is steady but not building over the equator west to the dateline. Everything is now looking like El Nino.
Nino1.2 Daily CDAS Index Temps: (12/21) (The official OISST temp record runs about +0.2 degrees higher). Today's temps have ben generally falling and today have fallen to +0.669 after being steady at +0.814 12/6-12/18. after building to +1.715 (11/27) and down at +1.0630 (11/20) after being at +1.657 (11/13) and up to +2.001 (11/6-11/10) then generally steady in the +1.9 degs range 9/28-11/9. Previous temps were down at +1.755 (10/22), down to +1.527 (10/6), up to +2.10 (9/17) and have been falling since 8/31 when they were up to +3.073 after rising to +3.164 (8/18) after being up to +2.925 on 8/10 after rising at +3.074 degs (8/7) after being up to +3.391 (on 7/20) and had been rising from +2.906 (starting 7/3) rising from +2.451 after peaking at +2.7926 on 6/13 and have been up in the +2.0 to +3.0 degs range since 4/1 having previously peaked at +2.891 (4/13). Previously temps reached +2.302 degrees on 4/6, +1.732 degs (3/22), up from +0.462 since 2/28. Temps had reached as high as +1.076 on 2/19 and were previously steady at +0.848 since 2/7. Previously they started steadily rising 11/13 when they were around -1.5 degs C.
Nino 3.4 Daily CDAS Index Temps: (12/21) (OISST runs about +0.2 degrees higher). Today's temps were steady at +1.496 after being up to +1.4660 (12/12) and up to +1.717 (11/22) after falling into +1.236 (11/16) after being up to +1.449 on 11/2 and +1.300 on 10/20 after falling down to +1.149 (10/11). Weekly OISST are up at +2.0 after being +1.9 (12/6), +2.0 degs (11/29) and +2.1 (week of 11/22 - the highest so far), then +1.9 the week before and +1.8 degs (previous 2 weeks). Anomalies were +1.6 the previous 2 weeks (10/18 & 1025), +1.5 the 3 weeks previous (through 10/11) after being up to +1.7 degs the week before and +1.6 degs 3 weeks in a row prior (starting 8/30) putting us in minimal strong El Nino status. Temps first time above +1.0 degs was on 8/7 after being up to +0.967 (8/1) up from +0.873 degs (7/25) after peaking at +0.985 (7/18). Previously temps were rising slightly at +0.882 (7/9) after being steady at +0.794 4-5 days and that after being steady at +0.895 (3 days near 6/25) after being in the +0.712 range the previous 9 days after previously rising to +0.975 on 6/9. We are now 31 days into a trend of being above the El Nino threshold (for the 2nd time). Temps reached the El Nino threshold for the first time on 5/17 at +0.507 then quickly fell over the next 10 days down to +0.378 (5/26). Previous peaks of +0.318 on 4/30 besting the previous peak at +0.199 on 4/21. Temps have been steadily increasing hitting 0.0 on 4/12 and were then more or less steady the previous 4 weeks. Temps previously rose to -0.402 on 2/23. Temps rose above the La Nina threshold (-0.5 degs) on 2/22 and had been rising slowly since 2/12 when they were about -1.0 degs C. They had been in the -1.0 deg range since at least Nov 2022.

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

SST Anomaly Projections
CFSv2 Data (Nino3.4 Region)
Previous - Temps bottomed out at at -1.25 degs in early Nov 2020, up to -0.01 degs in mid-June 2021 then fading to -1.05 degs in mid-Nov then rebuilding to -0.7 in mid Feb 2022 then fading to -1.1 degs in May before starting an upward climb peaking in mid-June at -0.65 degs and mid July at -0.55 degs. A steady decline set in after that falling to -1.00 degs in Aug and Sept rising to -0.8 degs mid Oct then falling to -1.0 in Nov but then slowly rising to -0.75 degs in Jan 2023 and up to -0.5 degs (above the La Nina threshold) on 2/12. Temps rose to +0.50 degs mid-May and were at +0.9 degs in mid-June, and +1.05 mid July reaching up to +1.30 degs early Aug, +1.6 degs in Sept holding in Oct and , +1.95 in Nov.
Forecast (12/21) - Temps to are to hold at +1.95 degs though mid Dec, then falling to +1.7 mid- Jan and solidly in strong El Nino territory before starting a steady fade thereafter down to -1.0 degs in Sept 2024. The PDF Corrected forecast suggests temp s falling to +1.6 degs in Jan. According to this version of the model we are at the peak of our strong El Nino.
IRI Consensus Plume: The December 20, 2023 Plume (all models) depicts temps are +1.67 degs today and it's the 8th month above the La Nina threshold. Temps to rise steadily from here forward up to +1.838 degrees in December (that's a 3 months running mean) then fading from there. The dynamic model suggest temps peaking at +1.900 in Dec/Jan/Feb before falling while the statistic models show +1.838 Dec/Jan/Feb before falling. This is higher than the previous months projections. The dynamic models are running a bit hotter than the statistic models and are likely more accurate. The CFS model is on the low end of the dynamic model range with 7 of 17 models above +2.0 degrees.
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 falling hard at -14.32 and has been negative 2 days. It was neutral the previous 8 days (12/12-12/19). Otherwise was negative since 12/3. It had been mostly positive the previous 8 days (starting 11/25) but was negative 5 days previous, neutral for 2 days then negative the previous 12 days, Previously they were toggling between weakly positive and negative for 12 days (starting 10/24), but were solidly negative for 65 days prior (starting 9/16). It was positive the previous 7 days, then negative the previous 29 days (7/14-8/11) with a peak down to -37.30 on 7/25.The SOI has effectively been negative since 7/12. It was positive the previous 21 days then was negative 11 days prior and positive 5 days previous then negative for 27 days previous ending 6/6 with a peak down to -29.32 on 5/31, -64.63 on 5/24 and -31.31 on 5/12. Previously readings were toggling between +10 and -10 for 13 days, but negative the 15 days previous to that, positive the 6 days prior to that after being mostly negative 25 days before that. It fell to -19.40 on 4/2. -17.44 on 2/22, the beginning of a change from which no return seemed likely. It was up to +21.85 on 2/10 and +55.74 on 12/22 and were in the +20 range the previous 22 days.
The 30 day average was rising at -1.51 after being down to -10.43 on 11/16 and up to -5.75 on 11/5 and previously down to -15.70 on 9/23. It fell below the neutral point on 7/26. It rose above positive 7/3-7/25. It previously fell to -19.64 on 6/5 had been falling to -4.13 on 4/4 (lagging indicator driven by the Active Phase of the MJO) after falling to -0.52 on 3/22 previously falling to +4.18 on 11/27 and peaking at +21.57 (10/16) after supposedly peaking at +19.66 on 9/28. It was down to +6.89 on 7/29. It peaked at +20.34 (5/12) the highest in a year and beating last years high of +19.51 (1/14).
The 90 day average was rising at -6.04 and turned negative the first time in years on 5/12. Recent max lows were -11.14 on 11/17, -11.85 on 10/15, -8.90 on 8/8 and -7.57 on 6/6. It previously peaked at +14.63 on 2/20, +15.61 on 10/25 and +12.92 on 8/11 and that after peaking at +18.40 (7/2) beating it's previous peak of +16.86 (5/31), the highest in a year. It previously peaked at +9.80 (9/21) after falling to it's lowest point in a year at +1.06 (6/9). The 90 day average peaked at +15.75 (2/23/21 - clearly indicative of La Nina then). This index is a lagging indicator but suggests that the Active Phase occurring now is starting to drive the index down, hopefully with no upward trend in sight for at least a year.

Pacific Decadal Oscillation
The PDO theoretically turned from a 16 year negative run (Jan 98-Feb 2014) in early 2014 and was positive till Dec 2019, but has been negative ever since, driven by recent La Nina conditions. In May-July 2021 it was the most negative its been in the -1.80 to -2.04 range since Sept 2012 (-2.99) and then fell to -3.16 in Oct 2021 (the lowest since July 1933) then settled at -2.72 in Nov and Dec 2021. Looking at the long term record, it seems likely we are still in the Cool Phase of the PDO (La Nina 'like') with no signs of moving to the positive/warm phase (El Nino 'like').

Local Interest
Stormsurf Video Surf Forecast for this week. See it Here
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