PAT CALDWELL

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SwellCaldWell Updated 3 PM Friday, February 14, 2025

DATE	SWELL HGT	SWELL DIR	SWELL PER	SURF H1/3	SURF H1/10	TREND	PROB	WIND SPD	WIND DIR	TREND
1 PM	4.5	WNW	14	7	9	DOWN		3-7	S	SAME
02/14	6.5	WNW	15	10	14	UP
	2	S	13	3	4	DOWN
SAT	9	WNW	13	14	18	DOWN	LOW	8-14	E	UP
02/15	4	W	11	5	7	UP	LOW
	2	S	12	2	3	DOWN	LOW
SUN	4	WNW	11	5	7	DOWN	LOW	3-7	S	DOWN
02/16	6	NNW	13	8	12	UP	LOW
MON	3	NNW	12	4	6	DOWN	LOW	3-7	N	UP
02/17	6	NW	17	12	16	UP	LOW
TUE	9	NW	16	15	20	DOWN	LOW	9-14	E	UP
02/18
WED	8	NW	15	14	18	DOWN	LOW	9-14	E	SAME
02/19

Table Definitions given after Discussion

Summary

Action Jackson has the wheel.

Discussion

Midday Friday 02/14 on northern shores has rising surf near the seasonal average from 285-320 degrees of 10-17s intervals. The long-lived WNW event dropped near to below average by dawn Friday as the new WNW kicked in midday. XL surf likely just after sundown Friday with elevated conditions holding Saturday.

On this day, 02/14, in the historical H1/10 visual surf observation Goddard-Caldwell database (starting 9/1968) for the north shore of Oahu, the average is 8.0 Hs, (16’ peak face, Oahu Surf Climatology) and the largest surf on this date was 18 Hs (sets 36’ peak face top spots) in 2008 from NW under 15 knot E winds.

Moon’s view

Central NPAC tracked a low across the Date Line to near Hawaii into Friday 2/14 to make for dominant WNW event 2/14-15, then short-lived NNW 2/16. Another winter caliber low near the Kurils 2/13-16 to make another long-lived, NW event locally Monday through most of next week.

Tokyo to central Aleutians then back to Kamchatka monster low 2/7-9

Backstory:
- Went said plenty stuff about this one already. If ya missed it– long-lived source filling NW to Date Line.
- Choke W component, good for those kine places no can say.
Pulse status:
- NW Hawaii NOAA buoy 51001 Thursday afternoon started hitting the breaks with a drop to near to below average winter energy. Next event on its heels (comments below).
- PacIOOS/CDIP Waimea buoy showed moderate to near average swell Friday morning.
- Cams showed sharp increase select spots N Shore Oahu midday 2/14.
Prognosis:
- Hana hou song was this morning, this event being swept under the rug by the big broom brushing over us locally 2/14 PM into weekend.

New Date Line low with 2-part surf potential 2/12-14

Part one, WNW—
Backstory:
- The new low formed 2/11 near 30N, 160E (2300 nm away), with mostly marginal gales over the 285-305 degree band nosing way out there beyond 2200 nm.
- Never gained major winter ooomfff, holding mostly lower to mid gales as it pushed a captured fetch east, reaching east Date Line 2/12 night, and to within 600 nm of Hawaii late Thursday 2/13. The 285-305 degree fetch pau Thursday PM.
- Proximity is the main key for this forecast—close means
Pulse Status:
- 51001 sharp rise in 10-17s energy, dominant 13-15s, Friday morning to noon.
Prognosis:
- Niihau/Kauai shadow on down-swell islands; active surf W-exposures all islands.
- Max near dawn Saturday
- Steady drop off Saturday night into Sunday from 285-305 degrees.

Part two, NNW—
- Once east of the Date Line Thursday 2/13, the low center jogged NE up N of 40N to N of Hawaii. It is taking more E track 2/14.
- Short-lived window over the 305-340 degree band, with mostly low to middle gales (small pockets severe gales beyond 1000 nm away). Already not aiming at Hawaii by Friday morning.
  - Onset near sundown Saturday 2/15 from 305-335 degrees.
  - Max Sunday morning from 320-340 degrees.
  - Xmas tree signature, fast up and down—well below average by Monday 2/17 from 320-350 degrees.

Kurils hurricane force low 2/13-16

A low deepened to ~950 mb off the Kurils Thursday 2/13. It occluded right away, coinciding with maximum strength (hurricane force), broadening of the gyre, and stalling of the track.
ASCAT satellite 2/13 AM and PM validated the extreme winds over large area. Wide fetch from 300-315 degrees.
Models show slow weakening Saturday into Sunday 2/15-16 in far NWPAC, while the low pattern stretches east to near the Date Line Saturday. Once east of the Date Line Sunday 2/16, the winds weaken and aim less at Hawaii (more to NE of Hawaii).
- Long-period onset Monday morning from 310-315 degrees. It should rise above average midday, approaching XL just after sundown.
- Max of event Tuesday 2/18 from 300-320 degrees, dominant 315, low-end XL.
- Slow decline Wednesday 2/19 from same direction.

Midday Friday 02/14 on the east side has breakers way below the trade wind swell average. Similar surf on Saturday.

Windward wind-head concerns —

Slim pickings.

East side surfer interests—

Breakers from trade wind belt at a minimum through Monday with slight increase Tuesday into Wednesday 2/18-19.

Midday Wednesday 02/14 on southern shores has highest breakers on W-facing exposures, with added small southern hemi S swell. Same same Saturday.

On this day, 02/14, in the historical H1/10 visual surf observation Goddard-Caldwell database (starting 1972) for the south shore of Oahu, the average is 1.4 Hs, (~3’ peak face) and the largest surf on this date was 5 Hs (10’ peak face) in 2015 from SW under 35 knot WNW winds— major kona wind swell.

Moon’s view:

Complex austral summer pattern with multiple parts 2/3-6 has been giving small S event locally Thursday to Friday, but it is expected to dwindle down over the weekend.

Part 1: Marginal gale SE of New Zealand (<4500 nm away) 2/3-4 with seas 15-20’ pushed NE as it weakened. Surf potential low.

Part 2: A compact severe gale formed east of Aukland 2/4 though strongest winds aimed at Fiji. Surf potential low.

Part3: This low moved SE as it merged with Part 1 2/5. The circulation then broadened, giving about 18 hours of severe gales over a wide fetch aimed at Hawaii centered on Wednesday night 2/5-6. It weakened sub-gale by 2/7.

PacIOOS/CDIP American Samoa buoy Sunday 2/9 showed deep water swell 3.5-4.5’ with wave periods near 14s. It is lowering 2/10.
Short- to moderate-period swell has a faster swell decay with distance.
Not bad locally last few days, way better than normal February situation.
Fading Saturday.

Into the long range, let’s see what Wooly Worm is up. Pau hana Friday, time for Rat Worm’s Sports Bar. There’s Wooly at the Bar, with Wormina giving him lots of Valentine kisses. What a nice big smile on his face. Good sign for surf. Slow trend down from 310-320 degrees 2/20-21, with new NWPAC source filling in locally weekend of 2/22 a notch above average from 300-315 degrees.

The next SwellCaldWell forecast will be issued Monday, February 17.

Climatology update (February 4, 2025) to include through January 2025:

Summary (click below for details of each)

North shore, month of January 2025: Above average for XL days (sub giant) in January, nsstat01 otherwise near to below average. For the start of the 24/25 season, looking good, above average for Xl to giant, nmstat09_01.

South shore, month of January 2025: Minimal from southern hemi but near average from west or local konas, ssstat01.

Wind-heads: January 2025: Fresh+ trades days wayyyyy below average, wwstat01 . So much for the positive correlation between enhanced fresh trades and La Nina winter months in Hawaii. Southerly konas average, with post-frontal N-component winds above average.

Climate Fun 1.

Monthly Stats

North Shore Oahu (1968-present):

January: nsstat01

February: nsstat02

March: nsstat03

April: nsstat04

May: nsstat05

June: nsstat06

July: nsstat07

August: nsstat08

September: nsstat09

October: nsstat10

November: nsstat11

December: nsstat12

South Shore Oahu (1972-present):

January: ssstat01

February: ssstat02

March: ssstat03

April: ssstat04

May: ssstat05

June:ssstat06

July: ssstat07

August: ssstat08

*Picts surf forecaster validation duties Big Wednesday 8/18/21

(photos Shredsniper.com, Mike Carroll)

September: ssstat09

October: ssstat10

November: ssstat11

December: ssstat12

Wind (1988-present, PC’s best guess):

January: wwstat01

February: wwstat02

March: wwstat03

April: wwstat04

May: wwstat05

June: wwstat06

July: wwstat07

August: wwstat08

September: wwstat09

October: wwstat10

November: wwstat11

December: wwstat12

Seasonal Stats

North Shore Oahu, 1968/69-2023/24; (full season, September to June): nmstat09_06

North Shore Oahu, 2024 new season (Sept-DEC): nmstat09_01

South Shore Oahu, 1972-2024 (March thru November): smstat03_11

Helpful links,

Oahu Surf Climatology

Island Shadows

Educational outreach: Waves 101– Why Surf Varies Time/Place

Table Definitions

DATE	Represents daylight hours in zones of high refraction (biggest surf spots for given incident swell direction, period and height). First row(s) in table refers to observations from buoys (swell) and cams (breakers) made for the time when the SwellCaldWell forecast was updated. Other rows refer to forecast for spell (~30-60 min) within daylight when arrival of maximum wave energy, or active envelopes, occur. This forecast tends to bias high for safety (and easier to ride a bigger board if surf is smaller than expected, than to ride a shorter board when bigger). Even under “steady” swell, heights vary spell to spell through a day.
SWELL HGT	Deep water swell (H1/3) height (feet) corresponding to a nominal (~3 mile) location offshore of Oahu seaward of the coastal shelf for the given incident swell direction. Deep water swell height from each unique wave-generating source is obtained by summing up all energy for wave periods > 10 seconds, which removes the wind swell. H1/3 is the average of the highest 1/3^rd of all waves coming in for the targeted high energy envelope spell from this defined source. Wind swell are defined for wave periods <= 10 seconds.
SWELL DIR	Deep water swell direction (from) centered on 16 point compass bands.
SWELL PER	Deep water swell period (seconds).
SURF H1/3	Breaker H1/3 (defined above) height (feet, peak face) during most active envelopes. H1/3 sets arrive about every 3 minutes with large variance.
SURF H1/10	Average of highest 1/10th of all breakers (feet, peak face) during active envelopes; H1/10 sets arrive about every 10 minutes with large variance.
PEAK FACE	Trough to crest height (feet) on shoreward side of breaker at moment and location along wave front of maximum cresting,
Ocn H1/100 Cleanup or Sneaker set	Waves arrive within a range of sizes. Surf zone enthusiasts emphasize the smaller percent of larger waves when communicating a report in an X to Y occasional Z format. The X to Y range is nominally H1/3 to H1/10. The Z, or sneaker or cleanup sets, are the H1/100, which is about 1.3 times the H1/10 (eg., H1/10=10’ gives H1/100=13’). H1/100^th sets arrive on average every 90 minutes with large variance. Thus your typical 2 hour session is bound to see at least one cleanup set.
TREND	Breaker height (wind speed) tendency during daylight
WIND SPD	Wind speed (knots) for nominal coastal location on the windward side relative to prevailing large scale wind (ie, east side under trades or S or W side under konas),
WIND DIR	Wind direction (from) centered on 16 point compass bands. LV refers to light and variable.