Wind & weather patterns

[meeeckja]

We are planning to cross the Atlantic and at a later stage sail in the Pacific . In order to plan the different crossings in an efficient way we need information about the wind & weather patterns of the different area's. I have been looking at the net but until now could not find any site giving this kind of info unless for surf and kite area's. Typical questions are:

In a certain area at a certain time ...
* what is the wind direction and force
* what are the weather conditions (temp , sea ...)
* tidal info

Many thanks

Jan

[captain465]

Try to GOOGLE "Atlantic sailing directions"

[imagine2frolic]

Maritime Safety Information

[Bash]

The seminal reference would be World Cruising Routes by Jimmy Cornell. It includes prevailing winds, currents, weather patterns, chart recommendations, waypoints, et cetera on over 1,000 routes.

[svHyLyte]

See Maritime Safety Information .


Merry Christmas,

Ho, Ho, Ho

[Hud3]

The Pilot Charts and Jimmy Cornel's book are great suggestions. In addition, it would be prudent to have the onboard capability to download weather forecast charts and data (from the various weather services and GRIB files from model runs) AND develop the ability to interpret them in the tropical and temperate zones.

[AnchorageGuy]

Try here

PassageWeather - Wind, Wave and Weather Forecasts for Sailors and Adventurers

and here

http://www.windfinder.com/

[Hud3]

Those are two really good sites, and I use them frequently. They're based on GRIB data, so you need to realize that it's global model data that hasn't been subsequently interpreted by humans (weather forecasters). The good news is that I've noticed by looking at Windfinder on a daily basis that it seems to overestimate the weather more often than not, i.e. the winds are somewhat weaker than forecasted by the time they actually get here. Usually!

[AnchorageGuy]

Hud, Actually might be better than once it is interpreted by a human. Haven't seen them do a very good job on average. We usually do better interpreting the charts and faxes ourselves than the "professionals" do. But this does take some years of practice and a good working knowledge of weather.

[Hud3]

Good point, Chuck! The GRIB data is actually pretty good, usually. I've spent a lot of time studying weather data and comparing it to what we actually experience. You get a "feel" for it after a while, but I still admire the knowledge and skill of the good forecasters. Dr. Jeff Masters on www.wunderground.com, for example.

[MarkJ]

You can download Ugrib for FREE! GRIB.US
and then you select the areas you want the weather info and download it for free. You can see whats going on over a period of time during passage planning. Its very useful for the long hauls.

[AnchorageGuy]

We also use and like Ugrib.

[Amgine]

The Pilot Charts are excellent choices for planning. There are several things to keep in mind, however:

• In general, the majority of the data was collected from the late 1800s to the mid-to-late 1900s.
• Due to the selectivity of mariners, the number of gales is under-representative. (Sailors choose to avoid sailing into bad weather, so they avoid experiencing - and then reporting - as much bad weather as may really be happening.)
• These are averages, over about 100 years, so your actual experience may vary dramatically. In a trades zone the wind may blow 75% of the time from one direction, but during the few days you're traversing that one region a weather pattern may easily alter that to dead calm, or wind from the opposite direction.

Jimmy Cornell's book is strongly based on the British Admiralty's book Ocean Passages for the World (OPW) - in some cases lifting the exact wording. The big difference is Cornell is much more easily understood, and he is focused on the needs of cruisers rather than of commercial sailing ships. However, where he diverges from OPW he does so on anecdotal evidence rather than research over decades. Sometimes good, because those anecdotes are more recent than 1954, but sometimes not good because it isn't averaged over time.

You may be able to avoid purchasing these texts if you have access to a library which has either or both, but these are important navigational tools. I suggest getting a copy of both (for the OPW, try to locate an old one, 1954 or earlier, which has the extensive sailing routes sections) and constantly compare and contrast them both when planning and during your cruises. There are similar ocean route planning texts in other languages; I used to have a list of these, and if I recall correctly there are good references in Nederlands, Danish, French, and Swedish.

Read cruising guides of the regions and routes you plan to sail. Depending upon where you are located you may be able to examine these in the library system. This will help you decide which, if any, you need to purchase for your trips.

[Tempest245]

I love this site!....so much great information!!...

[Ricky]

Good questions and a lot of good advice!

I am currently planning a trip from Mexico (west coast) to the Caribbean and on across the Atlantic to UK.
I am using this site amongst other:-
http://www.nga.mil/MSISiteContent/St...106/106apr.pdf

I know (as already said) that the information is an average.
I know that it is over a long sampling period and I know that it is subject to the reports of countless sailors.
But, having said this, that is precisely what is needed to give a general idea. It is not one persons opinion.

Weather changes on a daily and even hourly basis but trends tend to only change over many years. My advice is to look at the trend, take local advice and set your parameters for a weather window. Stick to those parameters and do not be bullied by the weather or calandar into changing your mind.

I have heard of a 'weatherman' in Canada and available on the SSB who will give weather advice specific to your boat and position. Does anyone else know about this?