To get the most out of the weather forecast information provided on this site we recommend you follow the Quick Start steps:
1. View the Forecast Site Tutorial
2. Set up your user preferences
3. Refer to the Forecasting Tips to generate the best forecast.
View the Forecast Site Tutorial
Introduction
Forecast Maps
Types of Forecast Maps
Understanding the Forecast Maps
Wave_Maps
Rain Maps
Weather Input File
Download Time
Forecast Graphs
Forecast Table
Preferences
Email Notifications
Change Units
Add/Modify Locations
Change Password
Add Product
Upgrade Product
Mobile Phones
Forecasting Tips
Frequently Asked Questions
Introduction
The forecasting maps/graphs found on this site are similar to the tools used by meteorologists to develop highly accurate forecasts for races such as the America's Cup. Whilst it may seem a little complicated at first glance, the small amount of time invested in learning these tools will help you understand the weather pattern and generate a very accurate forecast.
Forecasts are generated twice a day and in most regions around the world a new forecast is ready morning and at night.
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Types of Forecast Maps
There are three different resolution models generated by PredictWind, and consequently 3 different map views. These are activated by clicking on "Forecast Maps" on the right navigation menu.
Local 1 Day
- This forecast map shows the 1km resolution map for a 1 day Forecast. 1km is the highest resolution forecast available, and it is therefore the most accurate.
- The local map covers an area 90km x 90km and contains your selected forecast locations.
Regional 5 Day
- This forecast map shows the 8km resolution map for a 5 day forecast.
- The regional map covers an area 670km x 670km and contains your selected forecast locations.
- It enables you to see the large scale weather pattern that may effect your local forecast.
- The time interval between maps is 3hrs.
Offshore 5 Day
- This map shows the large scale weather pattern out to 5 days, at a 60km resolution.
- The maps are also displayed every 3 hours. This is the resolution used by the majority of free weather forecasts available on the Internet.
- The size of the forecast map is 3000km x 3000km.
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Understanding the Forecast Maps
Your forecast locations are always plotted on the maps, which helps you to identify your key areas of interest, and to orientate yourself on the map. The outline of the coastline is depicted by a white line. The Land (shown in green) can be turned on or off using the "Show/Hide Land" button.
Arrows on the map show the direction the wind is blowing to. The maps are color contoured to show the different wind speeds.
In this example you can see affects the Isle Of Wight has on the wind speed which is ranging from 5knts up to 20knts. The wind speed on the leeward side of the island (shown in blue) is significantly less than the wind speed on the windward side of the island (shown in green).
Note: Measurement units for wind speed, direction, temperature, rainfall, wave height and direction can be customized to your preference.
Using the Map Controls
To move forward and backwards in time place your mouse cursor over the time steps on the left hand time and scroll to your desired time period.
To Change between the two input sources click on "Change to CMC" or Change to GFS" buttons.
(Note: Basic Package customers only get 8km Regional Resolutions Maps)
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Wave Maps
The wave maps display data from the NOAA WAVEWATCHII model.
- The color contours show the significant wave height in m/ft. This is the average of the highest waves. As this is an average height, one should be prepared to encounter larger waves of up to 1.5 times the significant wave height.
- Peak Direction - The arrows show the direction of the main swell.
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Rain Maps
Rain Maps are shown in Local 1 Day at 1km resolution or Regional 5 Day at 8km resolution.
- The outline of the coastline is depicted by a white line. The land is shown in green and the sea is white.
- Black wind barbs show the wind speed and direction with the longer barb pointing in the direction the wind is blowing to.
- The maps are colour contoured to show the amount of rainfall.
Using the Map Controls
To animate the maps scroll your mouse cursor over the time steps on the left.
To Change between the two input sources click on "Change to CMC" or Change to GFS" buttons.
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Weather Input File
Where does this information come from?
Our weather forecasts are generated from 2 different weather input files, which have proven to be, after years of research, the best:
- GFS (Global Forecast System) - a weather input file from NOAA in USA.
- CMC (Canadian Meteorological Centre) - a weather file from the Canadian Meteorological Centre
Please note you are NOT viewing a GFS or CMC forecast, but a PredictWind Model forecast, that is initialised using the observations from the GFS/CMC models.
If both forecasts are showing the same results you can have a high degree of confidence in the forecast. If the forecasts are different, we recommend that you choose the model that is best matching the wind observations.
(Note: to change between the two sources in any map view select the "Change to CMC" or "Change to GFS" buttons.)
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Download Time
When a forecast map is displayed on your screen you will be downloading the images to your PC. The download time will depend on the speed of your internet connection. The time steps on the left are displayed in red until all the images are downloaded.
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Forecast Graphs
By clicking on the Forecast Graphs menu, you can display time based graphs of your custom forecast locations.
- The units for these graphs are selected by going to Preferences > Change Units.
- The 1 day forecast displays the forecast from the 1km resolution model.
- The 5 day forecast displays the forecast from the 8km resolution model.
- The 1km resolution 1 day forecast will be more accurate due to the higher resolution.
- Locations can be turned on or off by clicking on the name of the location in the key.
- To switch between a 1 day forecast and a 5 day forecast click on the "Show 5 Day Forecast" or "Show 1 Day Forecast" buttons respectively.
The graphs plot both the GFS and CMC weather model runs. The graph legend shows which model and which location each line depicts. Different colors are used to show the different custom forecast locations.
The vertical solid lines on the 5-day graphs show the time at midday for each day (1200hrs) while the vertical dotted lines shold the time at midnight (0000hrs).
It is useful to note the difference between the GFS and CMC weather outputs – if both outputs are similar you can have a higher confidence in the forecast.
In this example you can see the solid blue line (GFS) at 0600hrs is predicting winds at 14knots, whilst the dotted blue line (CMC) is predicting winds at 21knots. Therefore the forecast has an element of uncertainty until 0900hrs. However for the rest of the forecast, the match is close and so the certainty of the forecast is high.
Forecast graph showing one User-selected Forecast Location and two Weather Input File Sources (CMC dotted line & GFS solid line)
The graphing combinations are
Speed / Direction
Rainfall / Cloud cover
- Rainfall per hour, or cloud cover as percentage of total cover
Temperature / Pressure
- Temperature and Pressure - Please note that here temperature is forecasted over the water, and therefore in most areas will be significantly cooler than land temperatures for most areas.
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Wave Graphs
The wave graphs display data from the NOAA WAVEWATCHII model. The graphs show:
- Significant wave height (m/ft): This is the average of the highest waves. As this is an average height, one should be prepared to encounter larger waves of up to 1.5 times the significant wave height.
- Peak Direction (degrees magnetic/true) - The direction of the significant wave height. There may be other wind waves present, but this is the direction of the main swell.
- Period (seconds) – This is the interval between the wave crests and measured in seconds. Large and short period (<10 sec) swells should be treated with extreme caution as they can damage small vessels.
- Note: Waves graphs must be used with special care. The model resolution is only 120km and therefore the wave data may not be relevant if your forecast location is protected by islands or large reefs. In addition you need to check the correct wave data is displayed, for example: If you are on a narrow island verify that the graph shows data for the correct coastline.
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Forecast Table
The Forecast Table shows all of the information for both the CMC and GFS input sources for your location.
- Select the location you wish to view from right hand menu under the Forecast Table Tab.
- The first day shows the forecast from the 1km resolution model and will be more accurate due to the higher resolution.
- Days 4-5 show the forecast from the 8km resolution model.
- To navigate use the scroll bar at the bottom or select your desired day of the week from the menu on the right, this will automatically scroll to display the forecast for that day.
- You can toggle between the 10m above sea level wind forecast or the 40m above sea level forecast by clicking on the "Show 40m Wind" or "Show 10m Wind" button.
- You can view the wind direction in arrow format or select the "Hide Arrows" button to view the wind direction in a numerical format, (shown in degrees).
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Preferences Menu
On the left-hand menu of the forecast website you can set your preferences.
Notification Emails
Email notifications can be sent as soon as a new weather forecast is available for your location. You do not need to check the website to see if the forecast has been updated for your location, and you can easily see what times the forecasts are generated.
To activate or deactivate the email notification for each location select Stop/Start sending emails
Please note the Regional (8km resolution forecast) will be available approximately 1hour before the Local (1km resolution forecast) email notification is delivered. Checking the Regional forecast will give you an early indication of the Local forecast.
Change Units
Select the units and timezone that you prefer, and click on the submit button.
Add/Modify Locations
- Users are allowed up to six selected forecast locations worldwide.
- You can change these at any time, but you are only allowed six changes in a 12hr period.
- To add a forecast location you must select Add New Location.
- The six forecast locations are shown on the forecast maps, and these are the locations that are plotted on the graphs.
- To activate or deactivate the email notifications for each location select Stop/Start sending emails.
- Here you also have the option to include all Regional 1 day forecasts for maps and graphs. This allows you to view the regional forecasts in a 1hr time step, as opposed to a 3 hr timestep shown in the Regional 5day forecasts
Change Password
Change the system generated password to something more memorable. This is helpful when logging on with your mobile phone.
Add Product
This will allow you to temporarily add a product for 3, 7 or 30 days. For example if you are subscribed to the standard package, you can get the Professional product for 3,7 or 30 days.
Upgrade Product
This function will allow you to upgrade from one product level to another.
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Forecasts on Mobile Phones
To access the text forecasts on your mobile phone go to
www.predictwind.mobi
This mobile site is designed specifically for mobile users and excludes any graphics. Data charges to your phone are therefore minimized.
Note:
- The Mobile service is available to members with web-enabled mobile devices that support WAP2.0 or a XHTML browser. You can test if your device is capable by going to www.predictwind.mobi/phonetest from your mobile device
- Consult your mobile phone service provider regarding internet access fees
- There is no additional charge from PredictWind to access the PredictWind.mobi site.
- Forecast locations cannot be added or modified on the Mobi site. The locations need to be setup on your PC on the main forecast site.
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