A big part of the preparation in a long distance voyage involves when to leave and how to get where you’re going…actually that’s a major part of it. Luckily, there are some places to go to get that type of information. One of those places is a Pilot Chart.
With a pilot chart, you can select a specific month and determine what years and years of observed currents, wind speed, wind direction and the position of major weather patterns are. This is particularly important for the trek from Seattle to Hawaii because of the North Pacific High – depending on the time of the year it can be right between Seattle and Hawaii.
I’ve selected June or July as the time to leave because the location of the North Pacific High (NPH) is usually a bit farther north during those months (and there are a handful of races that kick off then so if they’re doing it then it must be right, right!?)
Using the Pilot Chart, you can select a broad set of courses to help determine the best way to skirt the NPH. The idea is not to drive directly through it because that’s a great way to get becalmed. So, naturally you want to navigate as close as possible but not through. The chartlet above shows the location of the NPH during the month of July. You can see that you can draw almost a straight line from Seattle to Hawaii – about as good as it gets. We’ll want to drive a bit south then south south west after we pass about San Diego. The fine details will be decided closer to leaving using more real-time data. Keep in mind, these Pilot Charts are not real time or up to date data with where the NPH is at right this minute – just aggregated data from years of collection. It’s best to consult actual weather conditions prior to departure.