How Reliable are Met Office Forecasts?

[Gludy]

I am becoming so fed up with the Met forecats I pay for that I am probably going to discard them and base the forecast on the barometric charts.

This weekend chart forecats show a high sitting right on top of England but the wind forecats for the Bristol Channel are still f4/5.

Over the last few weeks I have been checking met forecasts against actual weather and the barometric chart seems to have been a better guide.

As I am still needing a lot of experience in this, I shall probably continue with both and keep cross referencing to build up more confidence. The one hour for the next 6 hours forecasts seem failry accurate (I get them from my mobile) but the 24/48 hour forecasts seem to have only a lose connection to the barometric chart forecasts.

All observations welcome.



<hr width=100% size=1>Paul

 

[Deleted User YDKXO]

I agree with you. I got very frustrated by the inaccuracy of the Marinecall 2-5 day forecast. The Met Office say that the UK weather is difficult to predict but then I say, if thats the case, then they should'nt be charging extortionate premium rate line charges for their lousy predictions especially when we already pay for the Met Office through general taxation anyway
Now my boat is in the Med, I can tell you that the French weather service is no better. They give wonderfully detailed 2 day forecasts over 8hr time periods even with probability % accuracy. But the forecasts are just as hopeless

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[ccscott49]

See my post getting the wind up, they didn't forecast that! Nor the weather front which developed them!

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[Nev]

Foget Marinecall and buy a dual frequency Navtex. You can also try the several free web sites who have reasonable forcast data

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[Gludy]

I have a weatherfax with the Navtex option - so I have barometric charts available - that is now what I base the main forecast on.

I find Marinecall OK for the local 1 to 6 hour forecast.



<hr width=100% size=1>Paul

 

[kindredspirit]

I use a combination of Bracknell's synoptics and theyr.net and that always seem to come out right for me.

But when there's a couple of depressions out in the Atlantic it's always hard to judge the speed of the approaching fronts.

(Pity we don't live in the Azores ! )

<hr width=100% size=1>Kev.

 

[franksingleton]

This is an extract from a letter in a recent CA Magazine from a member (not me, I hasten to add)

<QUOTE>
In order to gain some insight into the accuracy of forecasts and since my home sailing area is the Thames Estuary, I have been examining free GFS forecasts from www.windguru.cz/int (presumably based on GRIB files) and selecting Minster, Isle of Sheppey; the forecasts are given for 3 hour time spans several days in advance. I also used the (subscription paid) MM5/WRF forecasts (9 km) from the same site.

The Isle of Sheppey Sailing Club has an excellent web site http://www.iossc.org.uk/weather/index.php with live wind and wind for the previous hour and 24 hours at Sheerness; this enables reliable comparisons to be made of forecast wind with real wind.

I have done this over several months. For moderate winds up to (force 4/5) the forecasts can be quite good. However I confirm Frank Singleton’s conclusion that one must often add one or even more Beaufort forces in strong winds - which makes these forecasts not very useful for planning. For example the 7th May MM5 forecasts for three consecutive one hour periods gave 13, 9, 10 mph whilst the actual winds were 18, 20, 27 mph. This indicates a maximum difference of about 3 Beaufort forces.

However, I find that reliable and free UK coastal forecasts are available from the BBC web site http://www.bbc.co.uk/weather/coast/coastalforecast.
<UNQUOTE>

To me, this seems to confirm that the meso-scale model used by windguru does not do a great deal better than the GFS. The comment about the BBC "Coastal Forecast" is interesting because the National Met services (eg the UK Met Office and Meteo France) are, as far as I know, the only ones that can run meso scale models with a good meso scale analysis. More effort goes into data collection, quality control and analysis than into running the forecast computation itself

The Marinecall forecasts are also taken from this same model. The "Coastal forecasts" are presented as applying to an area, which is sensible. The Marinecall forecasts are supposed to relate to a point, which is not credible. The forecasts are as good as is possible, given the observations available, the computer power and the science. However, they should always be interpreted as relating to an area of around 15 miles radius.

 

[BrendanS]

What is suprising to me, is this needs explaining in detail, as anyone who has read these forums should understand this by now?

Obviously not, as most people don't read all the posts and pick and choose topics to read, so miss out on valuable expertise in little read threads?

 

[hlb]

I dont bother with forcasts much. Debs does and is constatntly forcasting bad weather. Mosttly we have fast capable boats here. So you can get most places, before the weather kick in.

 

[RogerRat]

Yes, but you are one of the few that will go out most weathers. You've posted many reports of being out conditions where most of us wouldn't even untie the lines.

Of course, we have all been caught out in more than choice conditions but being caught out happens when believing forecasts. I don't much now, I like to do my own based various info available stating with the BBC Atlantic pressure chart.

 

[Gludy]

This thread has been dug up from 2003!!!!

 

[RogerRat]

Some things never change, the forecasts are still dodgy, we all argue about them, most don't give a toss and Michael Fish thinks it's going to be warm nd dry tomorrow! /forums/images/graemlins/tongue.gif /forums/images/graemlins/wink.gif




I'll bookmark it and bring it up in another 5 years. /forums/images/graemlins/grin.gif