The Shipping Forecast is a weather forecast covering the sea around the United Kingdom and Ireland. It has been broadcast four times a day on BBC Radio 4 since the 1920s.
The Met Office, the UK meteorological centre, produces it for the Maritime Coastguard Agency.  The forecast talks about lots of places, starting with  "Viking" in the northeast and going  clockwise around the British coastline until it reaches "Southeast Iceland" in the northwest. Sometimes the names are changed to keep them the same as in other countries. It is one of the first items on Radio 4 each day, and has been referenced in many poems and songs, including a poem by Seamus Heaney and a song by the British band, Blur (This is a Low).

Protocol 

There is a strict set of rules (a protocol) on how the forecast is written, and it has a limit of 370 words. It is always said in the same way and is around 9 minutes long. The language of the forecast is hard to understand unless the listener understands how the rules work. For example:  People listening to the forecast who know the protocol can understand it as "In the English Channel, there are strong winds, followed by a stronger wind in less than twelve hours time with some light rain, but good visibility". The numbers refer to the Beaufort Scale of wind strength. Imminent means within 6 hours, soon between 6 and 12, and later meaning after 12 hours. There are lots of other jargon used in the Shipping Forecast.

Sailing By 
An instrumental piece of music, Sailing By, is played before the 00:45 broadcast of the Shipping Forecast. It acts as a  between the news bulletin and the Shipping Forecast, in order to make the Shipping Forecast play at exactly the same time each day. This gives the Radio 4 controllers  if the programming of Radio 4 is running late. There was an  when it was temporarily taken off air for two years in 1993. Sailing By was written by Ronald Binge, in 1962 a light music composer.

Methods 
The Shipping Forecast is broadcast in many different ways, most famously, on the radio. BBC Radio 4, the radio station that the Forecast is broadcast from three times a day, can be listened to as far away as Denmark, or can be listened to anywhere in the world via the BBC's website.

Navtex 

An updated Shipping Forecast is broadcast six times a day from three Navtex transmitters placed strategically around the coast of the United Kingdom, giving information on the areas near to the transmitter. The three transmitters are called Cullercoats, Niton and Portpatrick, after the places they are at. Navtex is a type of radio communication that sends a message to a receiver that picks it up and changes it into text, like to a mobiles' text message. The Navtex messages can be received up to 270 miles offshore. Navtex is an acronym for NAVigational TEXt messages. Major areas of general Navtex coverage include the Mediterranean Sea, the North Sea, Japan and the coasts of North America. Navtex is one of the more common ways of receiving the Shipping Forecast when off-shore.

Coastguard 
The Maritime Coastguard Agency sends messages every three hours from their sixteen stations that are located by the coast. They also send important navigational notices  and a forecast that is for the area.  The "Maritime Safety Information" broadcast includes a part of the Shipping Forecast, specific for the area in question.

Other forecasts 
There are several related forecasts that are similar to the Shipping Forecast. The High Seas Forecast is similar to the Shipping Forecast in format and protocol, but is about the North Atlantic ocean, or 'Met Area 1'. It can be seen on Radio 4's website. It is also split into lots of areas, and some of them have the same name as in the Shipping Forecast.

References

Other websites 
Read the Shipping Forecast] 
http://www.bbc.co.uk/weather/coast_and_sea/shipping_forecast
BBC radio
Radio programs
Meteorology