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Wednesday, May 01, 2013

Day 14 and 15, Fun with Weather

Wednesday Noon

It has been an eventful couple of days on NAKIA. When last we checked in we had just made the turn towards the ITCZ. The ITCZ seems to have had other plans and decided to come give us a preview of what it has in store for us.

On Monday morning I had downloaded weather forecasts, call GRIBs (*), that indicated we would have good wind all the way down to the ITCZ. On Tuesday morning, the GRIB file had changed to tell us there would be NO WIND on Tuesday. Huh, thanks for the heads up.

What we got was real ITCZ like weather. No wind, big thunderstorms (with lots of wind for 15 minutes) and LOTS of rain. We got through it ok, with all the salt crust washed off the boat, thanks rain, and finally picked up what we hope will be the last of the North East trade winds late Tuesday afternoon.

Now that we've had some practice we should be well prepared for the ITCZ in two days.

* These forecasts are a part of a giant computer program that models the wind, rain, waves, snow, barometric pressure and temperature for the entire globe. When I access them I get the tiny little piece that pertains to my location. These computer models are not magic, they are based on experience and have years of work put into them by various agencies of various countries but they have to be given somewhere to start. Over land, where there are lots of wind meters, thermometers and barometers the input to the models is frequent and accurate. Out here, there are very few weather buoys and only one or two satellites which scan the surface of the earth to provide input data. It's these satellites that are the problem here. In November 2010, as we made our way from Nuku Hiva in the Marquesas to Hawaii, the USA's QuickSCAT satellite finally gave up the ghost and died. I'm not sure when it was launched, but it had far exceeded it's projected lifespan. QuickSCAT's job was to scan the surface of the planet's water and give wind and wave hight data to the global weather models. In order to keep the weather models running (they provide forecasts to everyone on the planet, not just yachts) the models were adapted to use an older, weaker, European satellite called A-SCAT. The problem is, A-SCAT being weaker, it often misses data that QuickSCAT would have caught. The model may not get informed of the weather condition for 2-3 satellite passes, especially if it's a small condition. So we sail along on NAKIA, getting GRIBs that tell us one thing and then all of a sudden they start telling us another. All because the US decided not to replace QuickSCAT when it was obsolete and still has not replaced it over two years after it broke down.

You can help! Call your congressman today and tell them that you want an new scaterometer satellite in orbit ASAP!

{GMST}19|32|N|109|34|W|Mexico to Marquesas Day XX|Day XX{GEND}