To most people, it will doubtless seem like I’ve had a disproportionate amount of fun researching this post, under the circumstances. Even my own husband has refused, point blank, to be educated in the mysterious ways of the Shipping Forecast – that lovely, lulling rhythmic poetry, made all the more romantic and mysterious for having been relegated from BBC Radio4 Digital to the outreaches of FM and LongWave…
This has been one of the most dependable threads throughout my life. The background soundtrack of my childhood: the BBC World Service echoing out of the tiny FM radio my dad still takes everywhere he goes; the pips and Big Ben, crowding around to listen to our birthday shout-outs (my request: I Wanna Hold Your Hand’ by the Beatles, my little brother’s either ‘Baby Jane’ by Rod Stewart or, brilliantly, ‘Lady in Red’ by Chris de Burgh). I never understood it, probably didn’t even consciously notice it, but come on – whose tense shoulders don’t unwind even just slightly at the sound of the words, “Viking… North Utsire… South Utsire…”?
Now for the first time in my life I find myself with a need to understand what the hell, “Dover: NorthWest backing SouthWest, four or five; slight, occasionally moderate; fair; good” means, so here I present to you my Introduction to Deciphering the Shipping Forecast. It’s been a bit like pushing peas up a hill with a fork at times, so any corrections will be gratefully received, and apologies in advance to the rest of you…
AN INTRODUCTION TO DECIPHERING THE SHIPPING FORECAST
The Met Office prepares routine forecasts and initiates warnings on behalf of the Maritime&Coastguard Agency whose responsibility it is to communicate with boats on conditions in 31 sea areas around the British Isles.
They issue 4 shipping forecasts per day at 2300, 0500, 1100 and 1700 hours UTC (Coordinated Universal Time – mostly synonymous with GMT). Each one covers a period of 24hours from an hour on – 0000, 0600, 1200 and 1800 respectively.
The format is to detail the conditions in each sea area according to:
– WIND (e.g. “NorthWest, backing SouthWest, 4 or 5”)
– SEA STATE (e.g. “Slight, occasionally moderate”)
– WEATHER (e.g. “Fair”)
– VISIBILITY (e.g. “Good”)
And any gale warnings in force
SEA AREAS AROUND THE BRITISH ISLES
The order of sea areas listed is more or less clockwise around the British Isles from the top, and they’re broadly grouped into 3 larger areas:
Cullercoats, Niton and PortPatrick.
Just cos I love the names, here they are in full:
South East Iceland
(Disclaimer: The question marks are ones I’m not sure if they’re in that supergroup or another smaller one that wasn’t listed!)
HOW DO THEY KNOW?
(Disclaimer #2: This next bit is where I started to go a bit wrong with my deciphering…)
The British coast is littered with a wide assortment of Marine Observation Sites, comprising various buoys, light vessels, island systems and land stations which in turn have their own litany of peculiar names, from Gascoyne and Brittany to the somewhat less poetic K1, K2, PAP, M1-6 etc etc.
Observations are taken regularly from these but they alone do NOT constitute the Shipping Forecast as they note more auxiliary information like air and sea temperature, as well as wind direction and speed, visibility and pressure etc. Relevant, but only partly formative. I can’t work out the extent of their influence, though presumably it’s reasonable or they wouldn’t go into such detail (the last 24hrs of observations from each observation site are detailed online). Presumably there must be many more land stations inland that help inform the weather forecast across the country…
I’m now going to give up and quote the Met Office website:
“The Met Office requires marine observations, not just from the UK and its surrounding waters (e.g. from the MAWS network), but also from the North Atlantic and global oceans (from ships, buoys and floats). The collection of marine observations is co-ordinated internationally through the Joint WMO/IOC Commission on Oceanography and Marine Meteorology (JCOMM) which has individual programmes for observations collected from ships and buoys. At a European level surface-marine observations form Voluntary Observing Ships and buoys are co-ordinated through the EUCOS Surface Marine programme (E-Surfmar).
These observations also support the Global Ocean Observing System (GOOS) and the Global Climate Observing System (GCOS).”
Excellent. Back to me: the relevant Marine Observation Sites for our crossing are the Light Vessels SANDETTIE and F3, and the Land Station MARSTON, which last I was gratified and relieved to see quoted as such on the link my dad just sent us for the wind forecast around Ramsgate: http://www.metoffice.gov.uk/weather/uk/se/ramsgate_forecast_wind.html
So I’m going to quit while I’m ahead and before I get bogged down in the murky depths of maritime meteorology, and move onto the last section – my favourite bit…
THE BEAUFORT SCALE
Right, nearly there.
The empirical Beaufort Wind Scale which the Met Office uses, describes a range of wind intensity based on observed sea conditions, from 0 (calm) to 12 (hurricane force). Incidentally, it’s always “hurricane force” in this context, never just “hurricane” as they’re a specifically tropical weather event and we don’t get them over here.
Each rating on the Beaufort Scale correlates to:
– a mean wind speed in knots (to convert knots to MPH multiply by 1.15)
– a specific description of the wind (light air (1), moderate breeze (4), near gale (7), storm (10)
– probable and
– maximum wave height in metres
– a specific description of the sea (e.g.: calm- glassy (1), smooth- wavelets, slight-moderate, rough, very high, phenomenal)
For MARIA ELISABETH to cross safely, we need no more than 3-4. Seems quite low for that bit of the Channel, where it comes careening around the corner at Dover KABLAMM! right smash into the North Sea, but it’s the narrowest point and R has done it many times before, so we default gratefully to his experience (although clearly we may need to wait a while for a calm sea).
So, 3-4 on the Beaufort Scale should look a bit like this, if it comes out right (this may call for more table skills than my iPhone can deliver, so I’ll fix it tomorrow if so):
Scale. Mean Knots. Wind Limits. Wind. Prob. Wave Height. Max Wave Height. Sea.
3. 9. 7-10. Gentle breeze. 0.6m 1m. Slight
4. 13. 11-16. Moderate breeze. 1m. 1.5m. Slight-moderate
Incidentally, the definition of a gale is EITHER an 8 on the Beaufort Scale OR gusts reaching 43-51 knots.
And there we have it. Needless to say, this is all explained in far clearer scientific detail on the Met Office website, should you by some miracle want to know more. I for one have had enough.
PS: just got back from my dad’s house where guess what item was, as ever, in pride of place on the bathroom shelf…