Help

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 PredictWind Tutorials
2. Set up the following

• Setup your Locations
• Change your Password
• Select measurement Units
• Setup your Alerts / Notifications

3. Refer to the Forecasting Tips to generate the best forecast.

 

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PredictWind Tutorials

Please click here to view the PredictWind Tutorials

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Contents

Introduction

Locations

Forecast Maps

Types of Forecast Maps
Understanding the Forecast Maps
Wave_Maps
Rain Maps
Weather Input File
Download Time

Forcast Graphs

Forecast Table

Preferences

Locations
Alerts / Notifications
Change Units
Change Password
Upgrade Product
 

Weather Routing

Weather Routing via Email

Trip Planner

Mobile Phones

Forecasting Tips

Frequently Asked Questions

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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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Locations

To use the PredictWind Forecast site you must first setup a forecast location in your local area.

To setup your location, select the "Location"  from the left navigation menu. Then select "Add Location".   We recommend you use the Search feature to quickly find your local forecast area.  Note: By selecting a red-yellow location dot closest to your local area, you will obtain the most accurate forecast. The red locations dots are 1km resolution forecasts, and will be more accurate than the yellow 8km resolution dots.

Note: If you are doing a long coastal, or offshore trip the best tool is the free GRIB viewer.

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Types of Maps

PredictWind display 2 types of Maps:

Forecast Maps 

Show the forecast overlaid on Google Maps.  The advantage is that you can zoom right in on your local area to see the true resolution of the model forecast. This will allow you to see the local wind variations caused by geographical, and thermal effects. The wind barbs are colour coded by the wind speed legend at the bottom of the map.

Contour Maps

The wind maps show the same forecast but the wind speed is colour contoured. These images are static, cannot be zoomed or panned. However they are faster to load, and clearly show the wind speed contours.  In addition you can view wave forecast maps, rain forecast maps, and real-time Sea Surface Temperatures.

Both the Forecast Maps, and Contour Maps show the three different resolution models generated by PredictWind. These are activated by clicking on "Forecast Maps" or "Contour Maps" on the right navigation menu.

Local 1 Day (1km Resolution)

• 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 (8km Resolution)

• 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 (60km Resolution)

• 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.

Global Coverage 9 Day (100km Resolution)

• This is available under the Forecast Maps, but not the Contour Maps
• The forecast is every 3 hrs
• Zoom and pan to the part of the world that you need a forecast.

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Understanding the Forecast/Contour Maps

Your forecast locations are optionally plotted on the maps, to help you to identify your key areas of interest, and to orientate yourself on the map.

The Forecast Maps use Google maps, so make it easy to identify your local area. You can choose between Map / Satellite / Terrain view (top right of Map) to help orientate yourself on the map.

The Contour Maps use the 1km resolution topography to generate the outline of the coastline,  as depicted by a white line. The Land (shown in green) can be turned on or off using the "Show/Hide Land" button.

Arrows on both map types 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 Contour 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 observation files, which have proven to be, after years of research, the best:

• GFS (Global Forecast System) - a weather observation file from NOAA in USA.
• CMC (Canadian Meteorological Centre) - a weather observation from the Canadian Meteorological Centre

Please note you are NOT viewing a GFS or CMC forecast, but a PredictWind Model forecast, that is initialized 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. With the Forecast Maps, it may take some time to download all the wind arrows whilst zooming in on your local area.  Please look at the status of your browser to see if the download is complete and ready to display the forecast.

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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 midnight for each day (0000hrs) while the vertical dotted lines show the time at midday (1200hrs).

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

• Wind speed and 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 forcasted 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 2-5 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.

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 6hr period.
• To add a forecast location you must select "Add 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 notification for each location select the green tick in the check box

Alerts / Notifications

 

Alerts

This great feature allows you to save time, by automatically monitoring the weather conditions. For example if you would like to know if the wind will be above 20knots on Saturday or Sunday, simply setup an alert. To setup an  forecast alert click on the "Locations" from the left hand navigation menu, and click on "Manage Alerts" on the location that you would like an email alert.

Follow the instructions on the screen, and click "Save".

To clear an existing alert select "Clear" at the bottom of the Alert page.

 

Notifications

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 the green tick in the check box

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.

Change Password

Change the standard "predictwind" password so that the access of your account is not compromised.

Change Product/Billing

This function will allow you to upgrade from one package level to another, change billing preference, and enter new credit card details


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Weather Routing

The weather routing is a powerful tool for yachts and power boats to display the optimal route for your trip.  You can optimize for fastest time or for comfort.

Settings defined:

100km Model Resolution

This allows you to route with the PredictWind 100km resolution models

• Ideal for offshore passages
• Forecast length is 9 days

1/8km Model Resolution

Allows you to route with the 1km or 8km PredictWind resolution models and will automatically select between these resolution models. The full route must be within the 8km resolution forecast areas. Blue boxes are displayed on the map so you can move the start and destination waypoints to the correct place on the map.

• Essential for coastal routes
• Better accuracy due to the high resolution

Land Avoidance

If this option is selected the routing algorithm avoids the land. This option is only available in the standard and professional packages.  The land avoidance uses 1km resolution data which will give great results in most cases. However even at 1km resolution, if a 1km square area has more water than land, it will appear as water for the routing algorithm. In addition the waypoint information is display every 30mins, 1hr, or 3hrs depending on the length of the trip. You will need to check the route does not cross the land, or any shallow areas, and is fit for navigation.

 

Start Time

The start time is the time that you intend to start the trip.  Please select the time zone that you want the output of the routing displayed. Generally this is the time zone for the start of the trip, but you can select any time zone you prefer.  The time displayed is local time and not corrected for daylight savings time.
You can click on the Now button to use the current time, and ensure that you have the correct time format.

Polars

Polars define the performance of the yacht/power boat in different wind/wave conditions. It is important to define this accurately, so the optimal route is correct. You have the option to choose the following

PreDefined

A list of  popular yachts are defined. Select the closest yacht from the drop down list.

Power Polars

This allows you to define a polar curve for a power boat. Simply fill in the boat speeds for the different conditions, and the performance curve will be calculated.

Sail Polars

Similarly this allows you to define a basic polar curve for a yacht. Simply fill in the boat speeds for the different conditions, and the performance curve will be calculated. VMG is the velocity made good upwind or downwind.

Advanced Polars

Allows you to edit and save your own custom polar curve to match the performance of your boat. Simply change the numbers, being careful to keep the same format, and spacing.  The polar will be automatically saved after you perform a routing.

Optimise for Fastest Time

This will optimize the route for the fastest possible time and minimize the journey length.

Optimize for Comfort

The most uncomfortable conditions are going upwind in strong wind conditions. For example you may want to minimize the time going upwind (less than 45 degrees) in more than 20 knots.  The optimal route will avoid (where possible) these conditions and take you on the safest and most comfortable journey.

Start the Routing

Simply click and drag the start (green) waypoint and the destination (red) waypoint for the desired trip and click on the "go" button. To quickly find a start or destination use the search feature and your waypoints will automatically be moved to these locations. In subsequent routes the start and destination waypoint locations will be saved.

You can also add waypoints along the route. Simply click on the "Add" button at the top right of the menu. This will force the route to navigate around islands, or other destinations that you may want to visit. The waypoints appear as white dots (near the destination waypoint), and can be dragged to the desired position.  Please see example on the left.

Note: The objective is to use the minimum amount of waypoints so the algorithm is free to find the optimal path

 

 

 

The Google map displays route for both the CMC and GFS forecasts. By clicking on the colored waypoint dots you can see the windspeed and time information. This will allow you to see at what time you will reach a geographic location, and correlate the wind information with the track.








The Routing table shows the weather information and track information for both forecasts. You can click on the "GPX" button to get a file of the waypoint information in the GPX (GPS exchange) format so that you can upload the waypoints to any GPS. The waypoint/weather information is display every 30mins, 1hr, or 3hrs depending on the length of the trip. You will need to check the route does not cross the land, or any shallow areas, and is fit for navigation.

 

Alternatively you can also display the route on Google Earth using the KMZ format. Simply open the file and it will automatically be displayed and saved on Google Earth.

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Weather Routing via Email

Weather Routing via Email is designed for offshore and Coastal passages where communication is only possible with slower and expensive Satellite or slower SSB data services.

This service will revolutionize the simplicity and cost of getting your weather data. Simply send a small email with your start destination and waypoint information, and you will receive a compressed file containing the weather information in text format, and a KMZ file with the track information that can be automatically overlaid on Google Earth. In addition a GPX (GPS exchange) file is also included so that you can upload the routing waypoints to any GPS. Typically this email is only 3Kbytes in size and usually 30-60 times smaller than the equivalent weather GRIB files. This will save you a huge amount on communication costs, but without any compromise on accurate weather information.

Email Format

Send to: route@predictwind.com

Subject: routing

Content of email

username
password
35 57.612s 175 17.874e
18 28.776s 178 01.350e

The first latitude/longitude is your boats position
The last latitude/longitude is the destination waypoint
If you have any waypoints along the passage just list them in order between the start and destination waypoints.

The start time of the routing is when the email is received by the PredictWind server.
Please note all other settings will be used from the last weather routing was done on the forecast website.
This keeps the routing email in a very simple and user friendly format.

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Trip Planner

The Trip Planner is a powerful tool for yachts and power boats to decide which day you should leave on your trip. It is designed for trips as short as 15 Nm or for long offshore passages of 9 days or more.  Using the weather routing algorithm the trip planner will perform an optimum route for the fastest time for Day 1 to Day 4. A summary table is provided so you can quickly compare the differences for leaving in the next 4 days. Simply move the start and destination waypoints to the desired positions, and click on the "Go" button.  Routes will be displayed for each day, and for both forecasts. The routes will automatically avoid the land.

The GFS routes are depicted by the solid lines
The CMC routes are depicted by the dotted lines.
If the routes are very close, they will appear as one line, hence you may not be able to see all routes.

Settings defined:

100km Model Resolution

This allows you to route with the PredictWind 100km resolution models

• Ideal for offshore passages
• Forecast length is 9 days

1/8km Model Resolution

Allows you to route with the 1km or 8km PredictWind resolution models and will automatically select between these resolution models. The full route must be within the 8km resolution forecasts. Blue boxes are displayed on the map so you can move the start and destination waypoints to the correct place on the map.

• Essential for coastal routes
• Better accuracy due to the high resolution

Start Time

The start time is the time that you intend to start the trip.  Please select the time zone that you want the output of the routing displayed in. Generally this is the time zone for the start of the trip, but you can select any time zone you prefer.  The time displayed is local time and not corrected for daylight savings time.
You can click on the Now button to use the current time, and ensure you have the correct time format.

Polars

Polars define the performance of the yacht/power boat in different wind/wave conditions. It is important to define this accurately, so the optimal route is correct. You have the option to choose the following:

PreDefined

A list of  popular yachts are defined. Select the closest yacht from the drop down list.

Power Polars

This allows you to define a polar curve for a power boat. Simply fill in the boat speeds for the different conditions, and the performance curve will be calculated.

Sail Polars

Similarly this allows you to define a basic polar curve for a yacht. Simply fill in the boat speeds for the different conditions, and the performance curve will be calculated. VMG is the velocity made good upwind or downwind.

Advanced Polars

Allows you to edit and save your own custom polar curve to match the performance of your boat. Simply change the numbers, being careful to keep the same format, and spacing.  The polar will be automatically saved.

Start the Trip Planner

Simply click and drag the start (green) waypoint and the destination (red) waypoint for the desired trip. To quickly find a start or destination use the search feature and your waypoints will automatically be moved to these locations. In subsequent routes the start and destination waypoint locations will be saved.

The Google map displays routes for all 4 days, and both the CMC and GFS forecasts. By clicking on the colored waypoint dots you can see the windspeed and time information.

Trip Planner Summary Table

Allows you to quickly compare 4 trips for leaving from Day1 to Day4, with the same start time each day.  For example if you start date/time was Monday at 09:00 the trip planner would compare trips that start at Monday 0900, Tuesday 0900, Wednesday 0900, and Thursday 0900.

Passage Time (days)         
Max wind speed (knots)    
Min wind speed (knots)    
Ave wind speed (knots)    
                               
% time upwind  (True Wind Angle is 45 degrees or less)
% time reaching   (True Wind Angle is between 45 degrees and 160 degrees)   
% time downwind  (True Wind Angle is 160 degrees or more)    
                               
% time 0-8knots    
% time 8-20knots    
% time 20-30knots    
% time 30-40knots    
% time 40+ knots   

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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.
• 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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