Wind forecast accuracy

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Seahope

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Before setting out today I checked the following sites:

1. metcheckcom
2. xcweather.co.uk
3. windfinder (iPhone App)
4. windguru (iPhone App)
5. MetOffice (iPhone App)

None predicted the 25 knot winds in the Solent which made berthing fun on our home berth :eek:

The highest forecast wind when I looked in the early morning for early evening was 12mph which is less than half the wind speed greeting us on our return. Is there a better source for more accurate forecasts?

I know that I can check bramblemet.co.uk to check the current and historic wind-speeds in the Solent to at least validate the inital wind model forecasts against reality.

On the positive side we did have a nice run over to Yarmouth for our first visit there. The harbour was full so we were instructed to pick up a buoy outside. For lunch we found the Blue Crab which served a really nice seafood platter at a sensible price :)

Another positive was that I noticed that the diesel price had fallen by around 6p a litre since last time I needed a top-up.

My skills were honed a little today whilst waiting in the queue for the lock in a quite narrow channel being blown constantly towards the channel marking poles and having restricted forward & rear space due to other boats.
 
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at the end of the day, all the forecasts are based on a very limited number of available models or combinations of them, sometimes with humans interpreting the the computer models which may or may not add something to the equation. So you take your choice really, as not one of them is going to be accurate each time, while one of them may be sometimes but not others.

PS it sound like it would help to read up on how forecasts are created, to help you understand the difficulties in relying on any one forecast, and the issues with scales (most models are on very large scales, and don't take local geography into account for instance)
 
BrendanS said:
at the end of the day, all the forecasts are based on a very limited number of available models or combinations of them, sometimes with humans interpreting the the computer models which may or may not add something to the equation. So you take your choice really, as not one of them is going to be accurate each time, while one of them may be sometimes but not others.
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(for Western Anglesey) they always seem to be hopelessly wrong. Wrong direction, wrong speed. I suspect the problem may be that they are +/- 12 hours out, i.e. useless.

Graham
 
you have to remember they are predictions, not statements of fact, and Anglesey probably doesn't suffer that much compared to other locations in that regard.

What would help is if the prediction came with % attached. Most forecasts have this capability. Eg 30% chance of rain, compared to 95% chance of rain. They aren't commonly used in the UK, because many people think the general populace wouldn't be able to comprehend.
 
GrahamHR said:
(for Western Anglesey) they always seem to be hopelessly wrong. Wrong direction, wrong speed. I suspect the problem may be that they are +/- 12 hours out, i.e. useless.

Graham
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Hmm
Not my experience
I use 'widguru' quite a bit
I select 'Rhosneigr' for the West side
Usually as accurate as any other system I have found

The Met Office or BBC 'inshore forecasts' I have found to be useless for boating 'inshore' around Anglesey

'from St Georges Channel to the Great Orme' etc etc are too general etc

Bear in mind though
You have to 'read into' forecasts

I generaly check out a synoptic chart off the tinternet and combine with winguru and xc weather

Then just put loads of wet weather gear on and be prepared for a 'battering'.

Islands like Anglesey and the IOM in the fickle Irish Sea area
You have to use the 'blind side' for pleasure
Must be the same in the Channel Isles and the Scottish Isles I reckon

Huh
Went from Holyhead to Menai 2 years ago
'Yer must be daft' they said in Holyhead
Nipped round the West side
Wind was '7'/ '8' easterly

No sweat.

As Brendan said, human error plus percentages have to be factored in.

Taint an exact science as Mr Fish found!:D

If you want a 'nice' forecast
'Metcheck' the peeps who dish that one out must be total omptimists:D
 
We often will use the Southampton weather site for the Solent area.
They offer live updates of all sorts of weather information and have
an extensive marine section too: http://southamptonweather.co.uk

We also use the bramblenet web but this seems to be behind times quite often,
but we may just have been unlucky. Good sailing.

plunder
 
Kawasaki said:
As Brendan said, human error plus percentages have to be factored in.
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No, I said the opposite. Most forecasts are computer model based, especially internet based ones. A few have human intervention. The % thing is about getting a better grasp of what is being predicted. This confusion, is why most forecasts don't use it.
 
plunder said:
We often will use the Southampton weather site for the Solent area.
Click to expand...

Which is just using a very general wide area forecast. They stick a southampton/solent label on it, and people believe it's area specific. It isn't!!! Seriously folks, you need to read about weather forecasts and where they come from, rather than just relying on them. They are not region specific, unless they have a lot of human input, and even then, the humans are not taking everything into account, and are mainly guessing about what the computer models are telling them with differing levels of success. Local forecasts can't on the whole to have a huge amount of human interpretation, so just buy computer forecasts which interpolate to a local level, which is basically guessing less accurately than the larger scale computer models
 
We also look at all the forecasts but rely mainly on www.theyr.com.
It is a subscription site (about £30+ per year) but is updated twice daily and over the years has proved to be the most accurate and well worth the cost. It predicts up to 5 days in advance which helps with forward planning.
 
BrendanS said:
Which is just using a very general wide area forecast. They stick a southampton/solent label on it, and people believe it's area specific. It isn't!!!
Click to expand...

The weather station they use is in the centre of Southampton and is therefore very area specific. All the infomation on the front page of the site is produced live from this station and is updated every 5 seconds, including the "Short Term Weather Forecast for the Southampton Area". The other forecasts they use are of course more general for the south west and south east of the country to indicate the weather fronts that are likely to affect the southampton and Solent area.

plunder
 
Why not do your own !

After a bit of practice and using the met office synoptics (perhaps at http://www.stronge.org.uk/charts.html ) and utilising the Geostrophic Wind Scale in the top left hand corner, realising that winds tend away from the high pressure (and vicky verky for a low pressure) relative to the isobar direction.

Hey presto - at least as good a stab at a forecast as the Met Office Inshore Forecast.

I will scream if I read one more time "west to south-west, veering north later force 2-3 perhaps 4-5 later and occasionally 6 in east/east".

Tom
 
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