Essential Weather Sites for Sailors |
A page of weather websites that sailors may find useful with some explanations of what the various sites provide and what the differences between them are.
| [Acknowledgements - The idea of a page of this form came from Martin Stubbs when I first started to use the Internet. Subsequently, with help from Martin, additional links and some words of explanation, the page grew like topsy with no real form. I have now tried to make it more logical and structured in the hope that leisure sailors and others will find it easier to use and, | therefore, of more help. Sailors will also find Martin Stubbs' own site very useful. Many of the links given are through Georg Mueller's site at Karlsruhe University. This is an excellent site that has much information far beyond that required or of use to sailors.] |
For a concise list of sites mainly providing charts click here For links to GMDSS, mainly text forecasts, click here.
| Computer Charts and charts beyond 5 days | Oceanic charts |
Satellite images | Sailing Forecasts | |
| Private Met Services | Weather data | Paying for Weather |
INTRODUCTION |
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| There are many sites on the Web that give weather links. Most range widely over a great deal of the science. One that is easy to use, is that run by Ant Veal who seeks to provide as general and impartial a weather resource as possible Some useful sites are listed at the Miscellaneous sites later on this page. I have tried to point to sites that are likely to be of help to sailors and to give alternatives since sites do have problems from time to time. I have also tried to indicate the uses to which some of the information can be put. For more detail on the use of forecasts, try links to other pages. |
The target is very much a moving one and I (with the continued help of Martin) will try to keep the page updated. It certainly is not and never will be exhaustive or definitive. I will try to deal with them when I am ashore. Please note that I am likely to be away for long periods during the "Summer" half of the year. I am then "off the air". Comments on the links, particularly their availability may be sent either to Frank Singleton or to Martin Stubbs. |
Principal Weather ServicesCharts |
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| The two main world centres are the UK Met Office and the US National Weather Service, Washington, which provide, by mutual backup, the worldwide service to aviation. Their numerical weather prediction models (NWP) are probably the most advanced in operational use. That is why many sites lead inevitably to products originating from the UK Met Office or the US NWS. There are, of course, many other Met Services, see the page on ECMWF and other Weather Centres. There are other important Meteorological centres whose products are relevant to European sailors. These include the European Centre for Medium Range Forecasting, the Deutscher Wetterdienst, Météo France, the HIRLAM group (Scandinavian and Low countries, Iceland, |
Ireland, and Spain), the US Navy. Each of these runs NWP models. For various reasons, output will differ from other models. Comparison between models is a useful way of gaining impressions about the value of a forecast on a particular occasion. Charts come in three forms. First, and most familiar to many, are charts that have some human input in the drawing of the isobars and fronts so that there is experience added to the computer output. Secondly, there are charts which are unadjusted computer output of the predicted pressure fields, but with fronts added by a forecaster. And then, finally, there are charts which are pure computer output of mean sea level pressure, and various upper air fields, these being un-amended by a human forecaster. |
SOLAS (Text) Forecasts |
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| Under the SOLAS Convention, weather forecasts for the open sea are produced by nominated countries worldwide. These can be obtained by Radio, NAVTEX, INMARSAT-C and, nowadays, via the Internet. More localised Inshore waters forecasts are usually produced by relevant | countries and broadcast on marine VHF, sometimes by NAVTEX and, also, by the Internet. National Weather Services producing these forecasts have access to the various NWP models so that these forecasts should be well founded. |
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| Links to meteorological information on the Internet are not guaranteed and therefore must not be relied upon. None of the links given here has any operational requirement to ensure that the information is up-to-date. Information provided by the National Meteorological Services via the Internet is not part of an operational service. Pages can and do change at no notice. The Internet, itself, is not part of an operational system. ISPs can and do take their systems off-line for maintenance with no prior warning. In particular, the system should never be relied upon for information when at | sea. It is supplementary rather than complementary to the GMDSS. Many sites provide information that has copyright restrictions and, in general, the information must not be used for commercial gain unless permission has been obtained either from the Meteorological Service concerned or from the provider of the information. All links are believed to be correct as at the date at the bottom of this page.
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| IN PARTICULAR and as a matter of good seamanship sailors should have the correct equipment (Marine VHF/MF Radio, LW Radio Receiver, SSB receiver, NAVTEX and INMARSAT/SafetyNETTM receivers) appropriate to their sailing waters and needs to ensure that they are able to receive warnings and forecasts provided as part of the GMDSS. | |
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| This contains a great deal of information about the Met Office, including its scientific programmes with detail about weather prediction models, climate change research, observations and so on. There are also some forecasts, including movie loops of charts, and satellite pictures. Abbreviated Hourly observations from around the United Kingdom are now available including a one week archive of the data. There is a similar archive for Global Data. More specific forecasts, such as MetFax texts, charts and Mediterranean |
For those who want to learn some basic synoptic meteorology, there are some very useful pages on the site. These page are commendably clear and should be part of any Yachtmaster, Coastal Skipper or Competent Crew course. There are good pages on identification of clouds, how they are formed and the associated weather. Links to Met Office information pages and forecasts are as below. . |
Met Office general information pages are at
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Fast Links to these and other marine forecasts are on the GMDSS page of this site.
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| Charts Modified by a Forecaster - see the Chart Page | |
| The UK Met Office Analyses (ASXX) and 24-hour prognoses (FSXX) for 00, 06, 12 and 18 UTC are issued every six hours. The analyses are now usually available on the Internet some four hours following the data time and the 24-hour forecast charts after another hour. The Prognoses are based on the computer output, but amended by forecasters in the light of their knowledge and experience. The UK Met Office Prognoses for 36 hours to 72 hours are produced in the same way, but only issued twice a day using midday and midnight data. They are available on the Internet some 6 or 7 hours after the data time.. |
Prognoses for 96 and 120 hours are issued once a day at about 2300 UTC. These 4 and 5-day forecasts are based on the UK Met Office computer model but with a long sideways look at output from other Met Services output, including that from the ECMWF, the US NWS, France and Germany. The product issued is a 'preferred' solution for the fourth and fifth day and may differ considerably from the raw computer output from the UK computer model. There are several alternative sources for these charts, If one link fails, then another may work. The size of each chart is about 60 Kbytes which is significant if using a mobile phone connection. |
UK Met Office Charts from the USAFE Public Web Site at Sembach see chart page for Analyses and forecasts from Sembach |
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| These charts are UK Met Office computer output simply with the addition of fronts. They also show areas of rainfall and areas of extensive cloud. These cloud areas are those expected due to fronts, and other large scale uplift of air that occurs with areas of low pressure, rather than areas of convection cloud. Apart from the cloud, the rainfall areas and the colour presentation, these charts should be very similar to those on MetFax. The addition of cloud areas makes these charts somewhat "fussy" and some might find that it detracts from their usefulness. | The site contains links to give 5 day forecasts for USAF bases in Europe and for European cities. The updating of the charts via Sembach is based on operational requirements and can be rather variable. It is quite often possible to get more up-to-date charts from the UK Met Office or by accessing the more specialised computer output from the UK Met Office NWP model. |
Charts from other useful sources |
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| One of, perhaps the most useful site of all is the US National Weather Service Marine forecast pages. Charts from the US and many other centres can be found on several good sites, such as the Georg Mueller's site and the Institute of Global Environment and Science site. At the Meteosail site there is a well laid out and comprehensive set of links to charts of vector wind arrows and a miscellany of other information worldwide. Apart from a few areas, it is not clear which weather service or services have provided the wind vector information. Clearly, they must be from one of the major NWP models, most probably the US GFS model. Other data sources are obvious from the product shown. The US Navy site has a number of products of interest to sailors. Some eg UK Met Office Charts replicate what is already on this page. One very useful product is a set of charts giving isobars and wind vectors. These are from the US Navy NWP model known as NOGAPS found, for example, at Georg Mueller's site
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The home page of the Fleet Numerical Meteorology and Oceanography Center gives numerous links to their charts worldwide. Downloads are a bit slow because of all the colour involved If time is not a consideration then this is a useful site. Click on Global Models, then select an area and a menu will appear. This lets you select a type of chart and a time up to 6 days ahead. Sailors will find the charts labelled Sea Level Pressure and Wave Watch Significant Wave Heights to be the most useful. An easy to use service is provided by PassageWeather to adverytise other services. Their chart service comprises charts of vector winds fusing GRIB files the US GFS model, An excellent "Jumbo site" for charts from many sources is Ogimet. NOTE - The USA gives wave height in feet. UK and DWD charts use metres. |
Unmodified Computer ChartsForecast Charts from UK Met Office to 6 days ahead |
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| These charts are pure computer forecasts from the 00 UTC and 12 UTC runs of the UK Global Model The charts are surface isobars PLUS the flow at a height where the pressure is 500 hPa. These charts are very much for the professional meteorologist although they do give a useful outlook out to six days ahead, twice a day. In particular, the isobars are clearly shown. The 500-hPa field is represented by a series of colours (a key appears on the side of the panel) while there are also the key 1000/500hPa thickness |
lines (e.g. 510, 528, 546 and 564 hPa) on these charts. The "thickness" is the difference between the height at which the pressure is 1000 hPa and that at which it is 500 hPa and it is a measure of the average temperature of the whole layer. Hence the forecast 1000/500hPa thickness can be a guide towards expected temperatures and whether precipitation is likely to fall as rain or snow (more details in text-books on Meteorology). Charts usually available some nine to ten hours after the data times of midnight and midday UTC. |
| Links to UK and ECMWF charts are on the Chart Page. Other links are at Georg Mueller's Wetterzentrale pages. | |
| NOTE ECMWF is a research organisation funded by 23 European Met Services and was charged, initially, with developing forecasts out to 10 days or more ahead. They now include seasonal forecasting. They run their computer model once a day only at about midnight but using data from observations made at midday. Charts are available by late morning and are already well into the forecast period. That is why the first chart broadcast is for T=72 hours (but only 2 days ahead by the time that it is available). |
Charts on the open part of their site go out to 7 days. It is useful to compare the output for T+120 and T+144 hours with charts for the corresponding time from UK Met Office and other centres. If they look broadly similar, then it gives some indication that the forecasts are on the right line. If they differ greatly then in suggests that the weather is in an indeterminate mood. |
Forecasts beyond 6 days |
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| Go to the MRF charts on Georg Mueller's site. Against the Sub Head 500 hPa. Bodendr, click onto the period that you want eg 240 hours = 10 days or, quicker, onto 9-panel film. The quality of the longer period charts is not terribly high and it should be noted that ECMWF, UK Met Office and the German Met service do not issue any charts beyond 144 hours ie 6 days ahead. Anything beyond 4 or 5 days |
really is entering the realm of scientific speculation at this stage. Caveat emptor - except that the charts are free on the Net! Using the US NWS GRIB coded service, predictions can be obtained out to 15 days ahead |
Oceanic Charts and Satellite Imagery |
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Charts with Plotted observations are on the Chart page.
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Satellite Images |
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The US National Weather Service Marine Forecast Offices and Centers provide links to their products as well as additional regionally focused information. Many and various weather charts can be found from this link. |
Many sites have satellite picture. One specialist site is Dundee: Satellite Imagery. NOTE - it is worth registering; there are no charges but they like to know who accesses the site. |
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Forecasts in Text |
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| Another page of this site gives texts of forecasts broadcast mainly under the Global Maritime Distress and Safety System. Like weather charts, virtually all of these originate from National Met Services. For forecasts in text form I always prefer to use the same sources even | though there is sometimes a cost involved. This is because I know the levels of staff training, the computer technology used and the organisations. Some of the products available from UK Met Office are given above. Many more can be found from the Met Office Home Page |
DWD Grid point winds |
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| The resolution of
the wind vector information is
not very great and is comparable
to the spacing of the 2- and
5-day "spot
winds" produced by the DWD
on Radio Teleprinter. Very
useful 3-day spot wind forecasts are
available from the Deutscher Wetterdienst.
There are four of these for
The Nordsee and Ostsee ,
From the English Channel to Gibraltar,
The Western Mediterranean
and
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NAVTEX and INMARSAT SafetyNETTM |
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| Forecasts on NAVTEX and INMARSAT SafetyNETTM. are GMDSS services readily available and broadcast at published schedules. The MCA is actively encouraging all sailors to install the necessary equipment. There are various problems with NAVTEX, one of which is that reception in harbours can be difficult due to interference etc. In such cases it might be | useful to use the GMDSS page . These give the texts provided by National Weather Services . The same or very similar texts are used in conventional broadcasts, such as the Radio 4 Shipping Forecast, the Météo France forecasts broadcast by CROSS, RFI and Monaco. |
Areas around NW Europe |
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The UK Met Office forecasts provides the definitive marine forecasts for waters around the UK. Other countries' services such as Météo France Marine site do likewise for their waters. Go to the GMDSS page where there are also links to most marine text forecasts around Europe. |
Because many British (and other nationalities) sail in the Baltic and the Mediterranean, this site has pages listing all forecast sources that I believe are useful for the Baltic and the Mediterranean. Because Iceland is out on its own and has a very good service it has its own page.. |
Elsewhere in the worldFrom time to time I will add links elsewhere as an when they come to my notice. South Africa has links to text forecasts, charts, satellite pictures etc. |
Tropical Storms, Worldwide gives much useful data on current tropical storms, their tracks and much historical data. Canadian Marine Information for marine and other weather information, primarily for Canada. |
Section IX |
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| Private Met Services | |
| There are a number of sites run by private weather companies where forecasts are available. Sometimes these are free and sometimes they are on repayment. I have always hesitated to give links to such services because I do not know to what extent these forecasts are based on the National Met Service output. Neither do I know the levels of experience and training of the staff. The presentation of forecasts by the private companies, eg Météo Consult, (now part of MeteoGroup) in France, are often very good. | A service that I can
recommend because I know some of the people is
WeatherWeb.
They provide a "talk to a forecaster" service and
also run a
Weather
School. Wherever they come from all forecasts from private companies should be used with the same care as those from the National Met Services. |
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Actual Weather reports For plotted charts of weather data go to the Chart page.
Latest weather reports - land stations |
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| Normally weather observations from land stations are made on a regular basis. For many stations this will be every hour. on the hour. Where the observation depends upon a human observer being present then the reports my be less frequent. Automated observing is increasingly coming into use and at some places the content of observations will vary depending upon whether there is a human to describe the cloud and weather or not. | At airports and military airfields there may well be more frequent observations, perhaps every 20 minutes, while the airport is open For information on automatic observing, see the page on wind measurement and visibility observing. For UK land stations, go to my actuals page. |
Reports from Ships, Data Buoys and Light Vessels around the UK and Worldwide |
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| There are four forms of marine observation, from ships of opportunity. from tethered buoys, from drifting buoys and wind observations derived from low orbiting satellites. Voluntary observing ships have made observations of weather on a routine basis since the 1850s. The data are most useful both as an every day operational resource and as the basis of an invaluable global archive. Ships normally report on a six hourly basis at 0000, 0600, 1200 and 1800 UTC. In the days if single manned radio operation, data were received mainly at 1200 and 1800 over the N Atlantic and at 0000 and 0600 over the Pacific. With modern communications from a keyboard, used by officers of the watch on the bridge, there may well be a better coverage throughout he day. However, decreased manning levels has led to some decrease in observations when ships are in busy waterways. Tethered buoys can only operate on the continental shelf in a depth of water not normally over 2000 metres. In the same category, come observations from light vessels, remote islands and oil or gas rigs. The data are from |
automated systems and may include sea state. At oil rigs there may also be some human component to the observation. For commercial reasons rig reports might not always be available since they might be used to give some indication of operating problems. Most data buoys around the UK provide data on an hourly basis. Drifting buoys are cheap, use once and be prepared to throw away, systems that normally only give pressure, air and sea temperatures. They are dropped into the ocean at strategic locations and then drift with wind and current. The data collection is by satellite and depends upon the time of the over-pass. Each buoy costs a few £1000s compared to the more versatile tethered buoys that cost around £100k. Satellite measurements of sea surface winds are made using the scattering of a radar wavelength beam. This measures wind speed pretty well but with a directional ambiguity. This is normally resolved through a quality control process involving internal consistency, data from other sources and the short period forecast. Data are unreliable where there is rain but this is indicated on the display charts of these "QuikScat" data. |
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This gives links to National Weather Services and other organisations worldwide. |
This site has some useful information that, curiously, does not appear on the Met Office site. |
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Of the University of East Anglia, Norwich, Norfolk. Big on climate impact studies. |
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European Centre For Medium-Range Weather Forecasts |
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UK Met Office, now at Exeter. Source of many forecast services. |
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Publishes high quality scientific journals and the popular magazine, Weather |
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Starting point for all Météo France services. |
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| Home page of the German Met service. Not easy to use. | |
Available via INMARSAT SafetyNETTM and other links to useful information. |
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Comprehensive links to computer forecasts, or products based on them, originating from major meteorological centres, |
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Links to UK weather data, past, present and forecast. |
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What it says. - an unexciting site but one that gives many answers to weather FAQs in a no frills, no nonsense manner. |
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List of sites around the world. In Italian, but easy to comprehend. Little explanatory text. |
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Quaintly named, useful links, well organised and set out. Mostly in German, but most are easy to understand. No explanatory text, using the site is an interesting voyage of discovery. |
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Well organised and clearly set out. Most titles are in English although the site owners are German. |
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General, well laid out site run by Met Office forecaster Jon O'Rourke. Rather aviation orientated but useful material for the sailor. Little description of the sites. |
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A good clear "one-stop" guide to Mediterranean forecasts. |
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| A "Jumbo site" with charts, data, text summaries and much more. Some is in SYNOP (professional Met) coded form. Other parts in plaib language. | |
I have seen and heard of many other sites but have often found them either too general and all embracing or, simply, not user friendly. There are bound to be many more sites that can be useful to sailors. When or if I hear of sites that look genuinely useful I will try to update this page. |
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Addendum - Charging for weather forecasts |
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| This is not confined to the UK. In France, for example, there are various services available from Météo France by telephone and Minitel or from Météo Consult, many at prices similar to those in the UK. Usually, some information is freely available as broadcasts by Coast Guards and MRCCs. Free information on many Web sites is either paid for by advertisers or is there as a "loss leader". In this world, there is no such thing as a free dinner! Under the SOLAS convention certain weather information is available free |
of charge at the point of delivery. The minimum requirements are for 24 hour forecasts plus a brief outlook for sea areas to be broadcast on NAVTEX and INMARSAT SafetyNETTM. . Within the spirit of SOLAS, but going beyond the minimum, the UK Coast Guard currently broadcasts Inshore Waters forecasts on marine VHF and on MF. Likewise around the coasts of most European countries. In a very welcome change of policy, the UK, like both France and Spain makes the same texts available on the Internet as a free service in the interests of safety. |
© Frank Singleton 2001