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Where to get Weather


The gruppenfuhrer of weather sources is Frank Singleton with his Weather site for Sailors. He has recently improved his Baltic coverage and is completely comprehensive on how to get information afloat. The following section summarises my experience, but I suggest you use Frank’s site as the main jumping off point.

The DWD (German Met Office) are probably the most accurate predictor for the region, as like the French and the Brits, they run their own Weather model. They publish two day, and three day forecasts on the Web. They are in German, but the language is easy to pick up.

Also on the Web, the Danish Met office (DNI) has recently updated its site. It publishes forecasts in English for sea areas up to 1 day ahead, and general area forecasts for up to 5 days ahead. It also publishes accurate graphical wind flow forecasts (just select your sea area). In Sweden, coastal forecasts are available by VHF or on the Web.

The most useful invention for the cruising sailor are GRIB files. Sailmail, a cooperative venture between sailors and radio hams, has an automatic system which will extract wind forecasts from the US model and email them to you. The major advantage, apart from being a free service, is that the files transferred are small, as you use separate viewer to access the files. This keeps costs down if you are accessing the net via a mobile. The downside is that the data is not interpreted by a human, so you run a little risk. Some charting systems (e.g. Transas) incorporate a GRIB viewer, or you can download one from the downloads section on the Sailmail site. Full instructions on how to use these things are on the GRIB section on Frank’s site.

We've found that Sailmail works reliably, and is generally pretty accurate. Our observation is that if anything it tends to underestimate the wind slightly, and the absence of weather fronts on the charts is a pity as you cant tell if its going to rain!

The situation has improved in the last couple of years with the advent of GRIB.US. This uses the same weather sources as Sailmail, but provides an enhanced and much easier to use viewer, which can be used to download the files interactively. The GRIB.US files include rain information, from which you can often infer the missing fronts. It also has a very useful metogram facility. Although the initial package download is large, and needs the even larger Microsoft .net package (no Mac facilities as yet), the file transfers are comparable. In fact, you can view the Sailmail fies in GRIB.US's viewer, and vice versa.

The Germans use Beaufort forecasts, but all the wind forecasts in Denmark and Sweden are in meters/sec, rather than knots. A sufficiently accurate conversion to knots is to multiply by 2 i.e 10 m/s = 20 kn or, for a good approximation, divide m/s by 2 to get the Beaufort force.

VHF Radio Forecasts

We make extensive use of the VHF services. Germany has an excellent forecast daily for both the North Sea and Baltic Sea coasts. It is in German, but is read at dictation speed in a stylized language, so it is easy to pick up. Coverage is reasonable throughout Southern Denmark.

Stockholm Radio gives navigation warnings and the Baltic Sea forecast, in English, every day at 9.32 (LT), and again in the evening. The forecast text is identical to that on Navtex, but arrives a few hours earlier and hence is of more use. Coverage is excellent for the whole Swedish coast, with a separate forecast for regions as little as 30 miles apart, but VHF channels vary according to location and change randomly about every 30 miles, and there is no logic to the channel layout. A channel map is available on the Stockholm Radio website which is well worth printing out and taking with you. The latest map contains channel and forecast information for the whole of the Baltic, not just Sweden.

Far more useful is the local coastal forecast. Unfortunately, it is in Swedish, but it is always in the same format and is relatively easy to pick up. It starts with an overview and then goes clockwise round the coast in sections about 50 miles apart. Each section starts with the risk of winds above 10 and 14 m/s, and then the forecast for each sub area. The broadcast has recently been spilt into two parts, with information for eastern Sweden being broadcast at 08:30 and 16:30 (local time) and for the west coast (as well as Vanern and Vattern) at 09:00 and 17:00. The morning forecast covers the morning (förmiddag), the afternoon (eftermiddag), the evening (kväll) and the night (natt). The afternoon forecast covers the evening, night and then before and after midday the following day.

The coastal forecasts are also available (in Swedish) on the SHMI site here. (You will need to select the area you need). It includes a useful 5 day prediction.

Navtex

Navtex in the region can be variable, although on this trip its been pretty good, just losing a few odd spots. It is a good idea to ‘program out’ the French and Mediterranean stations as they tend to come through at night and be a pain in the neck. The main drawback with Navtex in Sweden is that forecasts come through about 11:30 local time, which are not helpful for day sailing. The earlier Stockholm Radio VHF transmission is identical text.

HF Radio

On SSB, the DWD publishes 5 day wind forecasts for the region in Radio-Teletype format, and forecast maps in Fax format. These, at least, are free, if you have HF. Broadcast times and frequencies are on the DWD site separately for Radio-Fax and Radio-Teletype

To be honest, we've used the Teletype service occasionally, but reception is never stellar (maybe its us!). The 4783 kHz frequency has been the easiest to receive. By far the best use for the communications receiver on the boat has been to listen to BBC Radio 4...

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