Weather & Routing

Position: 05/27/09 1553Z 07 23.607N 79 47.995W

It has been a long 24 hours for sure. The lightning and ships are decreasing the further I get from Panama which is some consolation for the lack of consistent wind. My passage from Grenada has definitely got me spoiled! Winds have been flukey and light. I am making decent speed now though I am off course a fair bit.

There have been a ton of questions asked lately and I was just too busy to sit down and write much. I will get to them as I head northwards.

There have been a lot of questions about weather and routing for this leg. That has been the main focus of my last few days so today is a good day to write about it. For routing, I was given 3 different options for this leg by experienced sailor and meteorologist, David Morris.


Option 1: The longest offshore route. This track heads southwestward toward Galapagos, and actually passes close to, or even south of, the Galapagos Islands to pick up the trades south of the ITCZ with a southerly component. It then heads west to 0° 105°W, then NW to 20°N 125°W. This track passes well to the west of Clipperton, picking up the NE trades further north, then heading into the southeastern ridge of the North Pacific High before tacking on to port tack for the sail into MDR. Of course, strength and directions largely depend upon the positioning and development of the North Pacific High. This late in the year however, an extended offshore leg risks potent East Pacific tropical development with nowhere to run. Good enough reason I think for us to put this little option 1 firmly on the back burner. The advantage of course would be that an entirely offshore passage would avoid the small boat traffic that you get in near shore zones, which is a huge plus if you’re singlehanding.

Option 2: Hug the coast from Panama, along the Costa Rican Coast as far as 10°N, then head west, offshore toward Clipperton. From the vicinity of Clipperton Island head in a NW direction until at around 24°N 123°W you can think about tacking onto port tack to point up against the northerlies to MDR. Although the mileage of option 2 is more sensible as compared to option 1, the same caveats apply. That is to say that this late in the year, with the Eastern Pacific Hurricane Season about to kick off, it’s probably quite a good idea not to get caught offshore. Option 2 also has the advantage of avoiding strong gap wind potential in the vicinity of the Gulf of Tehuantepec.

Option 3: Hug the coast all the way as far as 20°N or even as far as the vicinity of Cabo San Lucas, before heading more NW, to diverge with the Baja coast, sailing close-hauled on starboard tack as far as 27°N 121°W. Then tack on to port tack for the close-hauled beat into MDR. The obvious advantage of this route is that relatively safe harbours are never more than 2 to 3 days away (max.). With the potential for East Pacific Hurricane formation never far away, that is about as far ahead as we can predict tropical naughtiness with a good degree of accuracy. After around 3 days tropical development may not always happen quite as predicted, but often does. Disadvantages of option 3 include the difficulties with nearshore traffic, and the potential for strong Gulf of Tehuantepec gap winds. These gap winds can be predicted fairly well, and nearshore traffic can be minimized by staying out of the immediate nearshore waters. The disadvantage of sailing further offshore will be an increased sea state, but steadier (less gusty) winds, during Tehuantepec gap wind events at least.


For now I will hug the coast as much as possible - aiming for 10 degrees north and then reevaluate. The area from about 10N to 20N is known for being the areas where hurricanes form this time of year.














This map shows this area of hurricane development.

Locations for formation of hurricanes in the East Pacific are the narrowest in the world, with a local maximum located near 15N latitude, 110W longitude.

This map may also help to show why when I left last year in the middle of June to cross the Pacific for Hawaii, hurricanes were not too big of a worry (though David may say otherwise!)


According David Morris:

The HWRF hints at a 1008mb low developing by 00Z on the 1st of June, at 9°N 109°W, but shows it fizzling soon after. Lastly, the NGP model hints at a weak low developing at 9°N 105°W by Jun 1st. Historically the first Eastern Pacific cyclonic development has started around the last week of May, so there’s a good chance that this system will come to fruition.

These are the dates of first named systems from 2002 to 2008:
Alma 29 May 2008
Alvin 27 May 2007
Aletta 27 May 2006
Adrian 17 May 2005
Agatha 22 May 2004
Andres 19 May 2003
Alma 24 May 2002

The big deal with this leg is weather and routing and will be reevaluated daily.

All for now - time to sleep!
Cheers,
Zac