Marine Weather Forecasts - Beginners

About this page

Beginners to cruising may find the multiplicity of marine communications, such as VHF and NAVTEX, and marine weather forecast sources confusing. This page will get you going with conventional sources and the Internet.


On this page -

Some Basic Meteorology

Many sailing instructors find that teaching meteorology is one level, at least, higher than teaching about secondary ports! For some good, clear and well informed instructional material see the Education links on the Essential Sites page.

Communications

The Communications page talks about the types of equipment that I have found useful.

Which Forecast?

What you use will depend on the type of sailing that you are doing. A one stop page is available on this site to get you started.

In brief, for planning purposes the German Mat Service (DWD) 5-day forecasts on Radio teletype are very useful. A sample of the output shows the kind of message that can be received with a low cost HF/SSB radio and a laptop computer.

This example is for the Mediterranean, but broadcasts covering the NW Europe down to Biscay are similar. However, I think that many will find GRIB code easier and more comprehensive,

For immediate use and passage planning then Marine VHF, NAVTEX, Public service radio, are all useful services.

Useful Internet links

For good and quick links to the texts of Shipping, Inshore waters , NAVTEX and INMARSAT-C forecasts, try the links on my GMDSS page. Terms used in other European languages are in RYA book G5, but a very full list of French terminology is on this site. See my pages for advice on using email and connecting to the Internet

All the UK Met Office charts can be obtained in one quick download.

This gives all the available UK Met charts at 12 hour intervals from the latest actual out to 5 days. For a full size chart click on a thumbnail. You then download the full chart. However, if you do not want to go online again or are using a mobile phone, then simply right click on a thumbnail, use copy and paste into Paint. You can then enlarge. That means that you get all 8 charts for a total download of about 120 k – two minutes on a mobile GSM phone. Otherwise there are several links for the same UK charts on my Essential Sites and Chartlist pages.

GRIB Files

To be able to get GRIB forecasts from the USA, first obtain the Viewfax viewer from my page on GRIB Viewers. Request forecasts by sending an email similar to that shown here:-

This is a request to Saildocs for a forecast each day for 4 days for an area 45 to 65 N, 20 W to 10E, for the times indicated. The times are hours from midnight. The winds are requested at 2 degree latitude longitude intervals. You can get 1 x 1 degree but the attachment in the reply will be 4 times as long when it comes back. To request this service for an indefinite time then put days=0. If the word "winds" is omitted then you will get forecast winds and isobars. The attachment to the reply would be longer by a factor of 1.5.

The reply will come every morning and will be in your mailbox by 0630 UTC, Putting the word “send” instead of “sub” and omitting "days=4" results in only one forecast, but it will arrive within minutes.

Fairly obviously, put in the numbers for the required area and days ahead. I do not ask for more than 5 days (120 hours).

The reply looks like this

Save the attachment to a file and then open Viewfax - the icon will be on your desktop. In Viewfax use File Open and select the downloaded attachment. The result will be something like the examples on one of my Saildocs pages. Up and down arrows will change times. The winds are shown as vectors. One long feather is 10 kn, one short is 5 kn, In the bottom of the screen you can read off the speed forecast at the cursor point.

The email itself is about 4.3 k and the size of the attachment is as stated.

GOOD LUCK!

You can experiment with size of area, number of days ahead, with and without isobars, and see the message size. When using a mobile GSM or GPRS phone, I keep it below 10 k and then block all incoming emails to my mobile that are >10k.

I hope that this will get you started and give you the interest to explore the rest of this site.


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