La Nina - North Pacific

[Donweather]

I was just wondering if anyone knows what affect a La Nina has on North Pacific swells, particularly on locations around the equator, but more so west of the international date line......ie N/NE groundswells generated in the Northern Pacific as opposed to W/NW.

After a sensational start to the Northern Hemisphere Winter swells (aka Hawaii and the tropical islands around the equator (PNG for one)), she's gone rather quiet on the N/NE groundswell front (and looks to remain relatively quiet for sometime yet) with the majority of the swell generating fetches aimed towards North America (ie W/NW), and I was wondering if this is attributable to the onset of the La Nina?? It seems to have pushed a lot of the low pressure systems way up to the north, with predominate high pressure systems over the North Pacific, and with most long term outlooks pointing towards a more sustained La Nina over the coming months, I was curious as to what affect this may have on the swells arriving over the equatorial tropical islands west of the international date line.

Does anyone have any thoughts/information/past experience that they'd like to share. I note that we were in a similar phase (weak La Nina) exactly around this time last year, so did anyone hit up any of the equatorial tropical islands west of the interational date line this time last year (late 2007/early 2008) and if so were they rewarded for their fruits of labour?

[Nick Carroll]

I'm not really sure of this don but I suspect that La Nina encourages western Pacific typhoons in the second half of the calendar year. These lil puppies tend to go extra-tropical and flare up near Japan, imitating the true Nth Pac winter pattern. So Hawaii, Micronesia etc get a bunch of early swell action. But then when the true winter pattern arrives and there's no more typhoons going extra tropical, thanks partly to more evenly balanced water temps across the equatorial zone, you get that deep flattened-out high crushing the weakened Siberian lows before they get off the block.

But nothing's really written in stone, some La Nina Nth Pac winters have been fantastic...and some El Nino ones have been dogs.

This yr there's been a lot of cut-off lows near Hawaii being fed by super warm wet equatorial air from the ssw that's being sucked up into the 10s and 20s latitudes by fractured high pressures. This is really dampening what might otherwise have been a really good Hawaiian winter...it should come good in the next week or so.

[Donweather]

it should come good in the next week or so.

Thanks Nick for the feedback. Curious as to why you're indicating it to come good in the next week or so.........is that because of this storm?

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[Nick Carroll]

Well kinda ... more just looking like a return to stable tradewinds ... along with the nice swell hit over the weekend just passing.

Near future looks a lot more like it should be at this time of the year -- both here and there.

[Donweather]

Oh OK, thanks Nick.

Here's hoping the Nth Pacific comes alive in mid Feb!!

[steve shearer]

Hey Don, I spent three months in the Phillos during the La Nina year of 1999. (Sep-Nov).
Seems that because of the increase SST's in the Nor-West Pac...the typhoon storm track was higher than usual.
ie instead of forming around the Palau/inter tropical convergence zone they formed much further north and spun up towards Japan more quickly.
We endured a month flat spell in the southern Phillos until we clued into the new storm track and chased it to the Northern-most tip of Luzon (which is usually typhoon alley) and scored big-time.
Also the "ameehan" monsoon would be affected.
This year sure is an interesting one as we settle into this quasi-Nina state....methinks the usual rules could go out the window.
Steve

[Donweather]

Thanks Steve. I was more interested in the short term (ie Northern Hemisphere winter) and what impact the growing La Nina pattern would have on the Northern Hemisphere winter swells as opposed to the Typhoon season.

But there does appear to be one common occurence between what I've recently seen on the weather models and what both you and Nick have been describing.....the lows appear to track further northwards than normal and hence for this time of year, that means a lot of the fetch is over the land masses up north, or at least some of the fetch (N/NE) is inhibited by the land masses due to the storms pushed up further north (by what appears to be larger high pressure systems below or to their SE).

Just my luck I head to the Solomons to try and catch some nice northern hemisphere winter swells and I betcha back home here in SE Qld pumps for the entire last two weeks of February!!!

Oh and I hope that bloody monsoon trough buggers off from up there sooner rather than later too. I don't like the amount of rain that's getting dumped up there at the moment....not too mention the moderate to fresh NW winds that go with it, which would severely limit our surfing options up that way too.

[Donweather]

Speaking of the North Pacific, have you guys seen that monstor of a storm brewing up there in a few days time.......pushing some serious W/NW swell straight bang at Hawaii!!!!

[Donweather]

Hey Steve,

I've been doing some research and it appears that the swell generating characteristics of the Northern Pacific winter are more associated/linked with the MJO than say the La Nina. I've started compiling (and still have some compilations to go) a historical database of Northern Pacific swell heights and periods versus the MJO phases, more so for the South Pacific Tropical Islands (as opposed to say Hawaii et al). I'll put the results up when I get more data entered into the database.

I noted your comments with respect to the MJO in your Swellnet SE Qld forecast last night and I was wondering if you'd care to comment on where you think the MJO (phase) may well be come say the middle to end of February (around 15th onwards). I realise that these things are more in the hands of the gods and history has shown the MJO to be a rather wild and variable beast (ie last February (2008) she scooted through some of the phases incredibly quickly) but I'd certainly appreciate your thoughts on the old girl.

Thanks

[steve shearer]

Hey Don , how much did you say a trip to the Solomons would cost?
hahahaaaaa.
Interesting to note the twin cyclogenesis in the SIO at the moment.
Would love to hazard a guess but seeing as I already have egg on my face from calling a proper cyclone season and it's almost Jan over and no sign of one in the CS, South Pac, I better retire to the nearest rock and crawl under it.
Steve

[Donweather]

There is actually one spot left on our trip Steve!!!!

But c'mon, give us ya best guess (MJO Phase)......if ya don't feel comfortable advertising it to the world at least PM me with it please!!! Pretty please!!!

[Donweather]

Arghhhhhh....wish I was leaving for my Solomons trip 10 days earlier. Check out this little puppy pushing off the Asian continent next week, sending down some rather lovely lines of N/NW groundswell to the Tropical South Pacific around the weekend of 6th/7th Feb (and beyond)......gosh I hope this trend continues well into February!!!

http://www.ecmwf.int/products/forecasts ... 9012612!!/