Who Trusts (uses?) BBC Weather?

[POD II]

Planning to go out in the Solent today so checked BBC weather forecast on-line.

Off shore forecast for Solent and Christchurch Bay says Heavy Rain but on-shore forecast says glorious sunshine.

I appreciate that there could be a risk of a shower off-shore but its always far more pessimistic than the on-shore forecast.

 

[Topcat47]

The BBC gets the shipping forecasts directly from the met office. Try googling SMRC forecast from source if you are only interested in the Solent. Even the coastal forecast includes Christchurch bay and the IoW has a local effect on Solent weather.

 

[POD II]

The Met Office (MRSC - I think that's what you meant) says less than 5% chance of any precipitation in the Solent and full sun.

 

[wizzer]

I always us the Met Office, marine weather section - the clue's in the name really

 

[franksingleton]

http://www.bbc.co.uk/weather/coast_and_sea/coastal/11#selected-location is a Met Office forecast straight off the computer.

http://www.metoffice.gov.uk/mobile/marine/inshore-waters gives texts of forecasts with human input – these are what you will hear on VHF.

PS. If you look at http://www.metoffice.gov.uk/public/...&fcTime=1462646700&zoom=5&lon=-4.00&lat=55.01 you will see why there was heavy rain (showers) at the start. Apparently, the computer is not too good at detailed rainfall prediction.

 

[wipe_out]

Honestly I don't think they have a clue when it comes to predicting good weather, not unless there is a massive high pressure right over your head.. Sure they can predict major weather events but as an example I looked last night and today didn't look like it was going to be a good boat day, turns out it was but my "crew" didn't like the forecast so we didn't go out..

 

[franksingleton]

Honestly I don't think they have a clue when it comes to predicting good weather, not unless there is a massive high pressure right over your head.. Sure they can predict major weather events but as an example I looked last night and today didn't look like it was going to be a good boat day, turns out it was but my "crew" didn't like the forecast so we didn't go out..

I do not know where you are but where we are, the forecasts over the weekend have been pretty good in terms of both wind and weather. I also do not know which forecast you were using.

I know that it may seem strange but getting detail right in a high pressure system can be difficult. A small and unpredicted change in wind direction or strength or both can make a layer of low cloud a little thinner or thicker. That can make all the difference between a nice sunny warm day and a cloudy rather cool one, a cloudy mild night and one with fog or frost. We probably notice such differences more than, say, a few hours error in timing of a warm front.

Some aspects of detail are now handled far better than in my day. Snow in the UK used to be a particularly difficult problem especially when it started as rain but evaporation and latent heat effects could make it cold enough for snow. In recent years, snow forecasting has been quite impressive. So have rainfall amounts in heavy rain situations. So have major storms. I would never say that October 87 will not occur again. I will say that it is highly unlikely that such a monumental near miss – which is what it was – will not be repeated.

I am not trying to make excuses for the Met Office. I am trying to get over the realities. Also, I may well be the only person in the YBW forums who has been on both sides of the fence and seen forecasts from the early post war (2!) era when it really was seat of the pants stuff through to the present.

 

[fergie_mac66]

Will correct that for you.

Who Trusts (uses?) the BBC

 

[aquapower]

Will correct that for you.

Who Trusts (uses?) the BBC

No

 

[POD II]

It was a LOVELY day afloat!


Had a pretty impressive view of a 'casualty' being winched off a moving yacht as we sped past. Hopefully just a training exercise?

 

[paul salliss]

Honestly I don't think they have a clue when it comes to predicting good weather, not unless there is a massive high pressure right over your head.. Sure they can predict major weather events but as an example I looked last night and today didn't look like it was going to be a good boat day, turns out it was but my "crew" didn't like the forecast so we didn't go out..

A number of times in the last two years we have wanted to go out but the weather was not looking great, we decided to poke our noses out on the basis that if it was indeed poor we could u turn and come back. Not once did this happen. The reality to date is that every time we have ventured out it has been better than expected. Perhaps do it that way, you can always do a u turn.

 

[jac]

I saw the same forecast and to be honest I just Ignored the coastal waters forecast. How the hell it could forecast heavy rain when the projections showed just showers in the area overnight (which was basically correct) I was expecting to see bands of rain along some fronts.

Frank - appreciate your input here and I do acknowledge that the forecasting is probably better. The issue is that the coastal waters forecast differs markedly from the forecast for surrounding land. The wind was forecast stronger (maybe believable as nothing to disrupt it). The temperature showed as being much cooler (again maybe believable as the sea is cool)

Looking at what actually panned out (e.g bramblemet) and the gusts were nearing 20 knots, not the 31 that the coastal waters forecast predicted.

But to then show effectively solid rain / showers when for the land surrounding the water you are forecasting wall to wall sunshine.

 

[jac]

A number of times in the last two years we have wanted to go out but the weather was not looking great, we decided to poke our noses out on the basis that if it was indeed poor we could u turn and come back. Not once did this happen. The reality to date is that every time we have ventured out it has been better than expected. Perhaps do it that way, you can always do a u turn.

I suspect that is deliberate. Err on the side of caution and if it puts some people off going out then fewer casualties who might then sue because the forecast didn't foresee strong winds.

 

[paul salliss]

I suspect that is deliberate. Err on the side of caution and if it puts some people off going out then fewer casualties who might then sue because the forecast didn't foresee strong winds.

I should have made clear I am talking sea state, not rain/ sun etc, not particularly fussed about all that, it is the UK after all, and that means you have to crack on, if you are waiting for a flat sunny day then the boat will not be used so much

 

[franksingleton]

We have a similar discussion in two plaves. You might like to see http://www.ybw.com/forums/showthrea...cast-somewhat-deceptive&p=5693344#post5693344 and other posts there. Is there any way of combining the two?

What several people in both seem not to understand is the concept of predictability.

 

[franksingleton]

I will put this on two threads as both are discussing the emotive but poorly understood problem of predictability.

First, one of my more pithy remarks. “Weather does not know itself to within one Beaufort force.” This is due to natural small scale structures within the system.

Second is an example that I have often given. Assume straight isobars, E/W up the English Channel. A pressure of 1000 at Southampton and 1004 at St Malo will give an average W F4. If pressure at Southampton changes by 1hPa the wind will be change by one force. In other words a change of 0.1% in the total mass of air over Southampton will lead to a one Beaufort force change in the average wind. Just think about the implications on smaller scales.

I am not defending the Met Office. Through my writings I have tried to goad them into issuing forecasts such as those by Denmark http://www.dmi.dk/en/hav/#danmark , Turkey http://212.175.180.126/DTS/sea.php and others. They will not do so unless someone brings pressure to bear. Who will? Not the RYA. Not the Yachting press.

But, even the most detailed weather models eg http://www.meteociel.fr/modeles/wrfnmm.php?ech=3&mode=3&map=330 or http://www.meteociel.fr/modeles/aromezoom.php?mode=3&x=384&y=384&ech=26&zoom=0 show patterns that are highly smoothed compared to what we experience. The scientific problem is that there are small structures that we can barely and may not be able to observe. These have short lifetimes. A Boscastle type storm might be predictable implicitly 12 or 24 hours ahead but not explicitly until a few hours ahead. Met services are trying to predict such events as severe storms, localised fog for airports and motorways. Details on such size scales could not usefully be included in any broadcast forecast.

It is a combination of a scientific and communication problems. What may seem obvious and frustrating to the user is far less obvious to the scientists but equally frustrating.

If anyone wants to take up the matter of what the Met Office does and does not issue freely to all, then get to your MPs. Make a concerted effort to get more out of them. In the end, it comes down to money and resources. Please all of you that really care keep pushing your MPs. That is probably a request made in vain. Also, even were far more issued we would probably do no better than at present. That is the nature of the problem.

In a post a couple of days ago, I said that we would probably be leaving Dartmouth for Guernsey on Wednesday. As of this morning, that still looks to be the case. On Wednesday morning I doubt whether we will not be really sure e just what wind strengths we will experience.