Chasing Weather Forecasts

When will I ever learn? I don’t know what part of me ignores good advice that I give others. It can be about weather, stocks, women or whatever, I’m very consistent, as I seem to consistently do what I tell others is a fool’s errand.

I suppose that makes me the fool.

How it looked on the day of departure for current conditions

Yep, I have certainly earned that this year.

Here are the four snapshots taking from Windy.com of the southern Pacific coast of Mexico taken on 30 April 2018, Monday. These shots highlight what I mean by chasing forecasts. This is different than waiting for the right weather window. That I also had done.

A reminder of some of the vocabulary I use.

Windy.com aka windyty.com is a pretty slick graphical user interface for the numerical weather forecasts that are produced by the National Weather Service, the Europeans, the U.S. Navy, etc. On Windy, at the bottom right of the screen, you can select the two or three models available to view: ECMWF 9km, GFS 22km, and in CONUS, the NAM 5km. The number that follows the model name is the grid resolution, smaller being better. If I was on the east coast USA, I would only look at the Nam. I trust it less on the west coast, since it’s near the edge of the model.

How it looked on the day of departure for the next day, Tuesday

In any case, no matter where I am, I always look at only one model, because I have no way to know which model is working best for that time, space and season.  I use the ECWMF because of the lower grid spacing (excluding the NAM). Next spring, as I prepare to move north again from San Francisco Bay, I will use the NAM and read the NWS forecast discussion for my area of interest. Nothing else. If you look at too much stuff, you will just get confused. (this is well documented, but I won’t go into it now).

How it looked on the day of departure for the next two days, Wednesday

While in Huatulco, I was waiting for the right weather window. I was hoping for 3 to 4 days of light or southerly winds (at any speed).  Looking at the forecasts, it seemed the week of 30 April was it.

I did well wait for the right weather window, what I did poorly was chasing the forecast.

Looking at the map that shows Tuesday 1 May, the Tehauntepec winds were blowing from the Northeast, and while there were northwesterly winds off the coast, there was that lighter blue area well off the coast with winds that seems to be northerly, then turning more northeasterly. That would have been great.

So, I left Huatulco with the idea of heading west longer than needed to try to get west of the stronger NW winds.

That’s Chasing Weather Forecasts. For the first 3 days it seems to work well. We did have light winds and when the winds did pick up from the NW, they were still less than 10 knots.

The problem was as the winds got stronger, we were so far off shore, 70 miles, that we were left with few good options. The 14 hours backtrack to Xtapa was the result.

If one has about capable of 20 knots, then the math changes significantly. Then it’s more viable to chase good weather. But when you boat plods along a fuel sipping 5 to 7 knots, it becomes impossible to get to the right time and place and then stay in that honey spot. Weather moves to quickly.

How it looked on the day of departure for the 3rd day, I’d hoped to be in that area of lighter winds 150 nm due S of Manzanillo. I don’t even know if it ever existed.

In the North Atlantic, Dauntless made about 140 nm per 24-hour day. In that same time, a low-pressure system will move 500 nm and the associated cold front will move even faster. There is no getting out of the way.

In this last passage up the west coast, I didn’t bother with weather forecasts once underway. All I needed to know was that once the stronger NW winds set in, they would get stronger before they got weaker.

Returning to Xtapa was the solution. Chasing areas for better weather, would have been a fool’s errand.

 

 

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