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Advise on learning Weather Forecasting

ignacio

Member III
Blogs Author
Last year I was reading one of the Pardey books where they recommended this:

http://www.amazon.com/Instant-Weather-Forecasting-Alan-Watts/dp/1574093177

At $10, I was quick to get it, and found it instructive for the novice.

I'm looking for advice on a good, easy to understand source for learning about weather analysis as it relates to sailing. I also want to learn how to use weather fax to predict weather patterns. I came across this app recently which interprets weather fax signals from short wave radio.

http://www.blackcatsystems.com/ipad/iPad_HF_FAX_Weather_Fax_App.html
 

Gregoryulrich

Member III
I need another time waster! My most recent has been cross referencing Garmin hydrographic charts with Google Earth satellite images, all the while daydreaming my trip.
 

Gregoryulrich

Member III
Well, the company I work for has been in dire straights for a while now and I was thinking I'd head to Central America if it goes under. Maybe shoot for a six month trip and see what happens. It seems like the perfect time to head out.
 

ignacio

Member III
Blogs Author
Get it done! Seems like there's never a perfect time. I'll be departing SF in a couple of months to sail back to my mother land: Southern CA!

Well, the company I work for has been in dire straights for a while now and I was thinking I'd head to Central America if it goes under. Maybe shoot for a six month trip and see what happens. It seems like the perfect time to head out.
 

Rick R.

Contributing Partner
Thanks for the timely info fellas! I'm leaving mid April and sailing from Pensacola to Marsh Harbor in the Abaco Islands and I definately want to be prepared (especially for the Gulf Stream).
 

Gregoryulrich

Member III
Steve Dashew. It's amazing that these books are offered for free. I lust after Beowulf every time I pass her by. I've only seen her out once. She was flying an enormous red gennaker. Incredible.
 

supersailor

Contributing Partner
Weather

The Power Squadron has a pretty good class on weather. It is worth looking into. Google U. S. Power Squadron and you can find out where it is being given.
 

Jeff Asbury

Principal Partner
Well, the company I work for has been in dire straights for a while now and I was thinking I'd head to Central America if it goes under. Maybe shoot for a six month trip and see what happens. It seems like the perfect time to head out.

Greg, I thought of you while reading the recent blog from my friends Sven & Nancy who are currently down in Costa Rica. This relates to weather prediction. Sven is attempting to try and understand the wind patterns that the locals refer to as Papagayos. Sven & Nancy are cruising on their Ericson 39B Senta II. I've been following their blog for over two years now. Good stuff!

http://www.sailblogs.com/member/exploration/?xjMsgID=348803

also see this Wiki link: http://en.wikipedia.org/wiki/Papagayo_wind
 
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Gregoryulrich

Member III
Greg, I thought of you while reading the recent blog from my friends Sven & Nancy who are currently down in Costa Rica. This relates to weather prediction. Sven is attempting to try and understand the wind patterns that the locals refer to as Papagayos. Sven & Nancy are cruising on their Ericson 39B Senta II. I've been following their blog for over two years now. Good stuff!

http://www.sailblogs.com/member/exploration/?xjMsgID=348803

also see this Wiki link: http://en.wikipedia.org/wiki/Papagayo_wind

I've heard the Papagayos can get pretty hairy. They sound comparable to our Santa Annas.

FYI, the U.S. Power Squadron came up a bust in Marina del Rey and the Coasties don't have a comprehensive weather prediction class. I might try an online course in addition to all of the reading material I already have. This seems good too.

http://www.amazon.com/Understanding-Weatherfax-Forecasting-Weather-Internet/dp/1574092154
 

windjunkee

Member III
There are no easy answers to that question. When I was asked to be navigator on one of the Transpac boats, I went to seminars on weather forecasting, went to Stan Honey's navigation classes and spent more time than I care to admit watching weather charts. I suggest going onto NOAA's ocean prediction center. You can get all sorts of charts, but the one I always look at is the 500 mb chart which you can spin up on a 72 hour cycle. What I have found helpful is watching the way the systems move. Near land wind is a lot less reliable from the larger charts because land breeze, headlands, geographic features in general can tremendously impact your weather, but you can recognize patterns if you start watching the charts on a daily basis and then compare to the localized results.

Weather faxes will generally give you the 500 mb chart and a grib file or two. From there you can sort of predict what is going to happen, but the wind direction is probably only accurate to within 40 degrees generally and wind speed is marginally better.

If you're going off shore, I suggest setting up an email system where you get your GRIB files emailed to you once or twice a day and you can open them up in Expedition if you have it or a program like UGrib which is free but tends not to interpolate for smaller areas (i.e. you may have only one wind barb in a localized chart area).

I have several books on weather forecasting. The one I can see from my desk here is called "The Sailor's Wind" by Stuart Walker. Mostly its a matter of watching the charts over time and kinda figuring out how the systems react. The various forecast models do the same thing and you can see how accurate they are. They are only truly accurate out to about 48 hours, reasonably accurate to 72 hours and its nothing more than educated guessing beyond that.

Jim McCone
Voice of Reason E-32 Hull #134
Redondo Beach, CA
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I think I have all Stu Walker's books. He's good on all dinghy racing tactics and strategy, not the least of which is reading short-term weather from terrain and sky. We raced against each other for many years at Severn Sailing Association.

Offshore I have come to think the main purpose of weather forecasting is simpler than we make it. It tells us which season and which day to go. At sea, it tells us which way to go to get away from the hurricane, and can help dodge gales.

My own forecasting skills were much more reliable on the east coast, with its parade of systems and rapid-changing temperature, wind and sky. And it was more fun.

Here in Southern Cal the weather is mostly asleep, or puts me to sleep, and when I look at the sky it usually says nothing at all.
 
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windjunkee

Member III
Christian,

The accepted strategy about Transpac Routing is to get offshore and as you approach the N. Pacific Ridge, you sail south until you hit the 1021 mb line and then slide into your slot and head southeast. It is NOT as simple as it sounds. I looked everywhere for that line. It is impossibly difficult to find. In fact, none of those pressure gradients are visible on the water. I studied the charts hour after hour, slept with one eye on the barometer, and when I predicted we were there, nothing but a southeast zephyr, flat seas, and no lines. Its voodoo, I tell you.

Jim McCone
Voice of Reason, E-32 Hull #134
Redondo Beach, CA
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Yup. Couldn't agree more, and that's exactly the point I'm making.

Offshore, the goal should be simply to understand the big picture. Race routing is an art in which, in my opinion, amateurs have no chance anyhow.
 
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