But What Weather?

After Sunday’s paddle, I got interested in the minutia of weather forecasts and all the varieties available to the sea kayaker. First, I got the standard BOM marine forecast for my area which spans Ulladulla in the north to Montague Island in the south. Here it is. After that, I collected the MetEye forecasts for the same area which are produced in three hourly increments. You can see all of these as well. There was very little happening on MetEye at 8 am so the first image is 11 am, then 2 pm then 5 pm. All paddlers should be off the water by 5 pm!

Finally, I went to Willy Weather and started pulling up forecasts scattered through the region. This is where things got both interesting and perplexing. Starting in the north of the region at Ulladulla, Willy Weather actually has a drop down list of seven different Ulladulla locations ranging from Ulladulla off-shore to Ulladulla boat ramp. This is clearly a case of precision without accuracy.

Further south, things get even weirder. I’ve pulled both the Meringo and Congo forecasts. These two beach side communities are four kilometres apart. At Congo, the southerly wind comes in at 20 knots, while at Meringo the maximum southerly wind is 11 knots. Finally, to Narooma near the southern end of the BOM marine forecast. Willy Weather offers no less than 10 different options for Narooma! I chose Narooma Beach but also looked at both Narooma Offshore and Montague Island. As might be expected winds peaked at 20 knots for both offshore locations (they were the same) while at Narooma Beach winds peaked at around 13 knots.

What to make of all this? The most obvious first. If a paddler is using Willy Weather, the exact location chosen matters and varies widely. If I used one of the off-shore forecasts, I would be planning for winds up to 20 knots, while my paddling buddy – who chose Narooma Beach is prepared for 10 knots. There is a world of difference between paddling in 10 knots and 20 knots and there are a lot of paddlers out there who will struggle mightily in 20 knots. Drive your car at 40 kilometres an hour and stick your head out the window and imagine that wind blowing at you while paddling. This could well explain my perplexity when I’m paddling with folks who report a widely different forecast to my own. When I think back to all the times I’ve rocked up with a very different forecast to my paddling partners, when questioned, these paddlers always report using Willy Weather. But which Willy? Who knows? On a short stretch of the NSW south coast there are over 100 options and varying degrees of congruence between those options.

It’s interesting as well to compare the BOM marine forecast with MetEye. I tend to think of MetEye as a finer grained forecast than the broad brush painted by the BOM forecast. Inshore winds on MetEye range from 10 to 15 knots to 15 to 20 knots. That fits well with the BOM marine forecast and a sensible paddler would go out prepared for up to 20 knots of wind. Prudent outdoor adventurers (in any sport) plan for the worst but hope for the best.

But look at MetEye at 2 pm, there’s a half dozen tiles that are green (15 to 20 knots) among a sea (no pun intended) of blue tiles (10 to 15 knots). Some folks might look at this and think that if they are at Burrewarra Point at 2 pm the wind will be, at most 15 knots, while if they are at the Tollgate Islands or even North Head, the wind will hit 20 knots. Conversely, staying near Tuross Head, only 5 knots of wind will be encountered. This is false precision and an artefact of the way MetEye forecasts are presented. When I see this kind of discrepancy, I ignore the small details and assume that, in the afternoon, the NW wind will be anywhere between 15 and 20 knots. With that assumption I am pretty much covered in terms of preparation.

Finally, the very last image is from Windy. This application seems rarely used by sea kayakers but I think it’s the best. The presentation allows much better visualisation of the weather patterns, there are four different models to choose from and you can easily compare the different models. If all the models are in agreement, you can feel more confidence in the forecast, while if they are discrepant you should assume uncertainty.

What to make of all this? Well, that’s up to you. I’ll continue using everything except Willy Weather for all the reasons explicated above.