Last Sunday, my friend Dan coughed up $500 and we went to a Pacific Cup sponsored weather seminar taught by Lee Chesneau. It was interesting to be in a room with 15 professional sailors who were all headed to Hawaii in the big Pacific Cup race and a legendary weather forecaster at helm, telling us what we needed to know so that they didn’t get caught with our pants down (Shorts or no shorts if you’re typical sailor). One of the things off Lee’s resume that stuck with me was that in 1991, during the “Perfect Storm” off of the Atlantic coast, he was in charge of routing different carriers groups for their transient to and fro for the first Gulf War.

Previous to this course, my understanding of weather was what I could get VHF, off the internet, cross referenced to a few websites that I would check to see what some “computer model” was generating, and a vague idea that I was going to somehow download this data (known as GRIBS) onto our sail planning software at sea. For sailing in the bay, our ipad usually had a 3g connection. As a kid, I remember the weather man standing in front of a screen motioning, but I hadn’t seen a guy like that in years. Boy was I screwed up when I walked into Lee’s class.

He drilled in right away that the “human factor,” a real honest to God person who interpreted the weather was an indispensable tool. As tax payers, we pay for it, we should “damn well use it.” By the end of the day, I understood why he was correct. Today, a lot of sailors rely on GRIBS, which are very detailed data layers that are generated by sophisticated computer models. These GRIBS provide a lot of data at any point that you click the mouse on your map. The problem that Lee pointed out is that information you just clicked into existence isn’t real. The computer is guessing and that guess if what you’re going to base some very important decisions on. The holy grail is the weather verification and predictions generated by the Ocean Prediction Center, which is part of NOAA.

Every morning at 00, around the world, hundreds of weather balloons are released simultaneously. As the data starts streaming back down to Earth, sailors around the world are taking precise measurements from the bridges of their commercial ships as they cross the ocean. Even airplanes are reporting the wind speeds aloft. All of these thousands of real observations are piped back to the OPC at NOAA and land on the desks of some of the best weathermen in the world. Lee used to be one of these hired guns that would fly into action, build accurate weather maps, not just at the surface, but also at different pressure levels above the surface, and create predictions about what was likely to happen. Then he would write his name on it for the world to see and send it to press. Around the world, at a predetermined time, thousands of navigatiors on ships big and small would fire up their SSB radios or satellite phones and begin downloading Lee’s best guess. At noon the whole operation happened again. Inbetween, updates are released. The bottom line is that the 96 hour prediction is something you might have to bet your life on. If it said that a gale was forming and you decided to change course to avoid it, you had to know which way to go.

Now, I know the details behind curtain. The wizard is a little less unknowable. By July, it is usual for a strong Pacific high to have set in between SF and Hawaii. This high will displace the formation of cold fronts to the North and out of our way. If we were racing in the Pacific Cup with the other guys, we’d sail south and southwest for three days until we can get into the southerly winds spinning off of this high, which will be on our starboard beam. If all goes well, that stable high will be there the whole trip to Hawaii. In addition, we’ll be well below the 5640 line on the 500 millibar chart, which means that the odds of a cold front developing below the high and interfering with us is very low. So, we’ll be in shorts most the way.

At least that is what I hope for those 15 intrepid souls. In 2007 and 2008, the high never set in. Instead, in the upper atmosphere, a strong cutoff developed which pushed a weak high far to the south. Too far for the racers. Some of the pack opted to head North, up into the territory were lows and nasty weather could be found. Others tried a southerly route with little success. This year is shaping up to be a La Nina year, which means unstable and hard to predict weather for them. Great.