Duplicat's Diary

Its all about the numbers
by Rick at 08:38:24, 2022-06-03 (day 2952)

When we left the Gold Coast, with a 10-12 day trip ahead of us, its not possible to get an accurate forecast for the whole route. Beyond 5 days and things become harder to forecast - more of a lottery. You think your can see patterns, but often they surprise you.

I don’t like surprises, particularly not weather ones. So I’ve been downloading a GRIB file of weather data for the whole area we’ll cover morning and night. We knew about the windy front when we left, but with that rough came the smooth (ish) downwind sailing we’ve mostly enjoyed this whole trip. But what about the second half of the trip? It looked like it would return to typical trade wind conditions from the SE before another flip around as yet another low transitions across.

So at the start, my weather forecast was 2.6MB each time. I’m downloading a rectangle of which the opposite corners just cover the sailing area I’m interested in. So for each mile we sailed east, we’ve reduced that area.

Tonight’s forecast is just 600KB to download. Its a handy reminder to me each morning and evening just how much progress we are making, despite it not looking that far on the chart!

And as it happens, we’ve been incredibly lucky with the weather. Despite the windy 18hrs, and the light winds this weekend, it looks like we’ll have some nice trade winds for the last couple of days and at a very good angle for us. Current thinking that Wednesday is our likely arrival day. I’d take this weather over beating to windward any day!