Met Office 12km model online - significant

[simonjk]

Hi all,

From this morning there has been a significant addition to weather information (model only) available online to sailors.

Weatheronline have started adding the UK Met Office NAE model. Sounds technical I know, but this is the higher (although not the highest) resolution North Atlantic area model from the Met Office.

Why so signifcant? Well it runs to 12km resolution and that compares to the usual 90km and 45km resulution offered by the American GFS as used by most web sites.

What is really useful (and to be used with caution) are the visibility forecasts.

I have to declared an iterest because I supply some forecasts to Weatheronline, but I would be making this post anyway as this is an important facility for all sailors.

Link is http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000 then select NAE model.

Usually warnings apply, this is essentially GRIB data (see my posting yesterday) but it is very useful.

Simon

 

[Blue5]

Weather

Thanks Simon, very interesting site with plenty of information. Could I ask the million dollar question.

As an avid weather watcher for both sailing and ballooning I seem to have a myriad of sites bookmarked on the PC, far more than I can ever check, If you had to pick say three or four to formulate a forecast for sailing what would they be. (Apart from your own)

 

[simonjk]

I'm asked this one all the time.

Firstly, pick two or three. Any more than that and you get infomration overload.

Secondly, make sure that the sites you pick are not all using the same data (most use GFS presented in different ways, but ultimately it is exactly the same data!) A good site will tell you the source of the data.

Thirdly, cehck the update time of the data. They should be updating withint 5 to 6-hours of the issue time (i.e. the midnight run should be online by 6am).

So, my pick for sailing would be:

1. Weatheronline.co.uk (not because I do work for them, but it is genuinely the best site for data and observations. There is so much on there, and a special sailing section too).

2. BBC Weather - this is the only place you will see the UK 4km model 9although only cloud and rain, not wind, but better than nothing).

3. Met Office - For the Shipping and inshore waters forecasts plus sat pics.

By using these three you have two (numbers 2 and 3) using Met Office data, and the third (1) using GFS datat for spot forecasts, but lots of other models available to view.

How are those 3?

Simon

 

[Blue5]

Thanks Simon, interesting you choose BBC, but given the reason I can see the sense. I try to get a visual representation of what I am expecting to see first of all by the surface analysis charts and then work from there.

Off now to perform a cull on the 50+ bookmarks

 

[toad_oftoadhall]

Many thanks, really appreciate that post.

 

[tudorsailor]

As I sail primarily around the Balearics, does the higher resolution model extend here.

I have looked at the site today for Spain and clicked surface wind rather than surface pressure. The image for "now" had so many arrows that I could not see the wind for the wind. If I moved onto the time shot for three hours later, the wind chart is readable. If I zoom in, the wind chart becomes unreadable again due to so many arrows. Am I doing something wrong?

Can I ask what three websites you would use for the Western Med?

Can you explain how some commercial sites (PredictWind) can offer 1Km resolution?

Thanks

TudorDoc

 

[simonjk]

Hi,

Pleased you found the bookmarks useful.

Tudor - I've looked at the Spanish wind forecasts and they look okay to me. Are you zooming in using the 'magnifying glass' too at the toop of the chart? When I did this they wind direction and speed became discernable, although they are very close together (but that is the higher resolution). Is this what you are seeing?

As for resolutions of 1km, I offer no opinion. The UKMO has one of the most powerful cimputers in the world and there best operation resolution over the British Isles is 4km. This can be extended to 1.5km over focused areas during periods of heightened interest, i.e. a snow storm. But it uses so much computer power that they try not to do this operationally (yet). For the area of Europe they use 12km (the NAE I mentioned above), globally resolutions are nearer 45 to 90km. The European Centre For Medium range Forecasting is Reading is listed as the worlds 25th most powerful computer (as of June 2009) and operates at 40km resolution.

I'd tend to use the GMDSS and also Weatheronline.co.uk for the western Med. But there are so many local effects in this region that very often local knowledge is best for coastal sailing, although once out at sea the models are reasonably reliable. Make use of the 12km NAE, it is good!

Does that help?
Simon

 

[Roberto]

As I sail primarily around the Balearics,

Tudor,
you may want to compare the UKMO NAE with this HIRLAM model from the Spanish national met office

 

[tudorsailor]

Can you give me the url for the Spanish Met Forecast that you found the image? I cannot find it even backtracking from the image's url

When sailing around Mallorca, I can get the forecast that they read out in English on VHF, off the Internet if I miss it. The trouble is that this is only a 24 hour forecast and surprisingly not very accurate even though it is local.

Thanks

Tudordoc

 

[Roberto]

Can you give me the url for the Spanish Met Forecast that you found the image? I cannot find it even backtracking from the image's url

When sailing around Mallorca, I can get the forecast that they read out in English on VHF, off the Internet if I miss it. The trouble is that this is only a 24 hour forecast and surprisingly not very accurate even though it is local.

Thanks

Tudordoc

oups sorry I thought I had copied it, here it is

Oleaje is significant wave height, Viento en superficie standard 10m height wind speed

http://www.puertos.es/es/oceanograf...n_de_oleaje_PdE/Mapas_de_Viento_y_Oleaje.html

Under this other link actual buoy reports are compared with the nearest model forecasts

http://www.puertos.es/es/oceanograf...n_de_oleaje_PdE/Graficas_de_Verificacion.html

 

[Roberto]

When sailing around Mallorca, I can get the forecast that they read out in English on VHF, off the Internet if I miss it. The trouble is that this is only a 24 hour forecast and surprisingly not very accurate even though it is local.

Thanks

Tudordoc

If you click on "Proximos dias" you get the outlook for the following couple of days, IIRC it is broadcast on just a couple of the several daily VHF transmissions

http://www.aemet.es/es/eltiempo/prediccion/maritima?opc1=0&opc2=1&zona=bal1