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Home » Weather and Routing » South Pacific 2015/16 ElNino timetable

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02/09/2015 12:20:20

Martin Rutt<br>United Kingdom<br>DreamCatcher
Martin Rutt
United Kingdom
DreamCatcher

Posts: 16
This coming (northern) winter season is widely tipped as likely to be strongest El Nino to date, but what could that actually mean for a passage through the Pacific to Australia?
I am definitely not a meteorologist and this prospect has concerned me for some months as I plan my passage in 2016.
As a result, I have researched what appear to be key issues and offer the results to anyone who is also planning such a voyage, as well as anyone who can add to the debate and help me make a safe and enjoyable passage.
These results employ past years' data in the context of what is happening to actual Pacific sea surface temperature, wind and currents this year.
One major objective is to avoid the probability of Cyclones. To me, their strength is irrelevant - I don't want any! Secondarily, but still importantly, I am also concerned about the strength and maintenance of the primary East - West direction of the wind and current.
Historical data shows that key features of El Nino years are that Cyclones are stronger, more frequent, extend the season, and happen further east than usual; and that the normal East-West currents and winds are somewhat reduced and even reversed with significant consequences for travel time and fuel burn.
The key resources I have found to inform my views on the Pacific crossing timetable follow:-

Sea surface temperatures (SST):

If you look at the 29th June and compare the map with the 31sh august, it gives an idea of how the ocean temp is changing this year. It would be prudent to check again later in September and so on, here:-

http://www.ospo.noaa.gov/Products/ocean/sst/anomaly/


Cyclone activity:

I found it interesting to see what were the earliest and latest cyclones, and where they hit. These are shown in the part entitled 'Seasonal summary' of the following resource. Each year to date can be found and contrasted with the stronger El Nino years 1997/98 and 2002/03. I was interested in the Eastern extent (Marquesas etc) for Feb/Mar/Apr/May and the Western extent in Jul/Aug/Sept
My search entry was for 'South Pacific Cyclone activity......(year eg 1997/98)'. If you scroll to the bottom of the page there is a link to other years:-

https://en.wikipedia.org/wiki/2011%E2%80%9312_South_Pacific_cyclone_season


Westerly wind burst:

This is the phenomenon that I am told triggers the start and reinforces the continuation of the El Nino process. It was the absence of such that avoided the otherwise 'ideal conditions' last year turning into the predicted El Nino.

http://wattsupwiththat.com/2015/05/19/the-recent-westerly-wind-burst-in-the-western-equatorial-pacific-could-help-to-strengthen-the-201516-el-nino/


Pacific equatorial current flows:

A key consequence of the process itself, and a guide to where the favourable E- W current can be found

https://bobtisdale.wordpress.com/2009/02/16/equatorial-currents-before-during-and-after-the-199798-el-nino/



Daily wind direction:

Look for whole Pacific wind map for daily situation. The other maps are always interesting eg pressure and waves:-

http://www.passageweather.com


Routing:

The RCC Pilotage foundation produces 'The Pacific Crossing Guide' with excellent supplementary notes. At the beginning, the section on 'Timing the Voyages' recommends starting a Pacific crossing in early March;

http://www.rccpf.org.uk/ppgs/pacific_routes/route_p3.pdf


Conclusion:
The 2015/16 El Nino effects are currently predicted to last well into the spring of 2016. With previous strong event years bringing cyclones as far east as the Marquesas as late as April/May it would seem to be prudent to arrive in that region as late as possible.....consistent with having a worthwhile amount of time for the Ocean crossing and arriving in Australia in good time before the next Cyclone season.
I would welcome any thoughts.
edited by Martin Rutt
United Kingdom
DreamCatcher on 06/09/2015
edited by Martin Rutt
United Kingdom
DreamCatcher on 15/09/2015
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18/09/2015 18:01:11

Martin Rutt<br>United Kingdom<br>DreamCatcher
Martin Rutt
United Kingdom
DreamCatcher

Posts: 16
Some good stuff out there on this fascinating subject. The latest from Noaa:

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

is a good read, but I noted pages 22 and 23 in particular. If you click on the link that brings up all previous years, but especially the strong El Ninos such as 1997 and 1998, see how long it takes for the 'anomaly' to get back to zero......................implies how long into the next year that El Nino (and La Nina) conditions prevailed.
P 23 gives Noaa's current prediction ..................of a 55% chance this one will last into AMJ quarter.
This site is should be worth watching. It is updated on the 2nd Thursday of each month.
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