FAQ

Forecast Source

Forecast Accuracy

Notification Emails

Forecast Access

Billing

Yacht Racing Rules

Support

Forecast Source

What do PWC & PWG stand for?

PWC stands for PredictWind CMC forecast, and PWG for PredictWind GFS forecast.

The forecasts are generated by the proprietary PredictWind model using the weather analysis files from GFS (Global Forecasting System) and the CMC (Canadian Met Centre). You are not getting a GFS or CMC forecast but a PredictWind model forecast (PWG or PWC) that is initialised using the analysis from the GFS/CMC models. The PredictWind CMC/GFS forecast is run at up to 1/8km resolution (in many areas) so that you can compare the forecasts and have greater confidence in the accuracy. You can read more here, and read more about the modelling process and physics here.

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Forecast Accuracy


Will the PredictWind weather model perform better than other models available?

Yes. 10 years of extensive and comparative testing during Americas Cup yacht racing, and the most recent Volvo Ocean has proven the model to be the most reliable and accurate for wind prediction.
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Will the forecasts always be accurate?

Like all other weather models available, it relies on a weather input file which can be comparable to a photographic "snapshot" of the earth's atmosphere. If these inputs are inaccurate, the model forecast is likely to be inaccurate. Fortunately we provide you with two forecasts twice daily created by independently generated weather input files. If there is a discrepancy between the model forecast and real time observations of more than 30 degrees and/or 5 knots the forecast should be discarded. This will happen in approximately 15% of cases.
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Are there certain weather situations that the model will perform poorly?

If the conditions are light winds (less than 8knots), expect the model performance to be degraded. This situation relates to all models, as the atmospheric pressure forces are weak in light air situations, and therefore it is harder to capture these forces accurately. During the early morning or late evening the wind strength can be overestimated by the model.
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How does PredictWind compare to other web based forecasts?

Many web based services (including services such as US Grib, Windfinder, WindGuru, MetView, BuoyWeather, and SeaBreeze) use the freely available GFS model from the USA Met Service (NOAA).  Whilst the GFS is a good weather model, and free, it is only run at 60km resolution and therefore does not capture the local topography effects. At PredictWind we run our own proprietary model at 60km/8km/1km resolution capturing the local topography effects to produce a forecast of unparalleled accuracy. Please see the resolution video to gain a better understanding of the impact on resolution on accuracy.
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What happens if the forecast is wrong yesterday, should I still trust today's forecast ?

Yes. The process has no historical memory. Each model run starts with a new input file, and so you are best to put your trust in the PredictWind forecast.
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How accurate should I expect the forecast to be?

The forecast is generally accurate to +/- 3 knots +/- 20 degrees. This is an averaged wind strength and direction over a 1km area and a 20 minute time period. This does not account for gusts, or convective cloud related activity.
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Notification Emails


How do I turn off the notification emails?

Logon to the forecast site with your username/password. Select from the left hand menu > Locations. Next to the relevant location deselect the relevant check box.
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How do I know when my latest forecast is available?

You may choose to activate the forecast notification email functionality. Logon to the forecast site with your username/password. Select from the left hand menu > Locations. Next to the relevant location select the relevant check box.
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Forecast Access


How many times can I logon and access the forecast?

Unlimited times for the billing period that you have subscribed to -  3 months, or 1 Year.
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How many times can I change the forecast locations?

Unlimited, but restricted to 6 changes for each 6hr forecast period.
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From how many computers/devices can I access the forecast?

You can access the forecast from any 3 devices (the system looks at your IP address) in a 6hr period. For example you can look at the forecast at your home PC, then work PC, and Mobile. If you try to access from a 4th device  (or 4 IP addresses) within a 6hr period  you will be logged off the forecast site and your password changed. The new password will be displayed on the website for the 4th device, so that you can continue to access the forecasts.  This is to prevent users abusing the system and passing on their username and password. Please note our Terms and Conditions state the license granted is solely for your own personal use.
Note: The process is refreshed every 6 hours, so you can logon from unlimited devices, so long as you respect the 3 logons within a 6hour period.
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How do I access the PredictWind site when using a mobile connection, with an IP address that is changing regularly?

So long as you do not use the "logout" menu from the forecast site, or close your web browser, it does not matter if the IP address of your connection changes.
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Billing


What happens at the end of the 3 months or Yearly billing period?

A reminder email will be sent 2 weeks before your subscription expires regarding the next billing date. You have the option to cancel and use the free version.


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Can I upgrade between Product Levels?

Yes. This is possible at any time will all subscriptions. During the upgrade process, the current subscription is automatically canceled. To do this select from the left menu Billing > Change Product/Billing
Note: Refunds will credited to your next purchase, but not exceeding the amount of the new purchase.

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Yacht Racing Rules


Is it legal to use PredictWind whilst racing?

Rule 41 of the Racing Rules of Sailing (RRS) state "A boat shall not receive help from any outside source, except ..." , and the exception 41 (C) which states "help in the form of information freely available to all boats;"

The interpretation given for the words “freely available”  as used in RRS 41(c) was "free of cost" for all competitors. Therefore during racing, competitors are limited to only using the free package of PredictWind. Before the start of the race competitors may use the PredictWind paid packages.

The Notice of Race/Sailing Instructions for any particular event may impose less restrictive limitations on receiving weather information. It is therefore the competitor responsibility to check the rules for that event, to ensure they comply.

If you have any questions please contact us at support@predictwind.com We would welcome any feedback on this important issue!

Is it legal to use the Satellite Communicator whilst Racing?

The Satellite Communicator is a communication device and so therefore complies with rule 41 of the racing rules of sailing. 

Does the weather routing have any human intervention?

The PredictWind Weather Routing algorithm runs on the PredictWind servers, with no human intervention. Therefore this cannot be interpreted as outside assistance, as it is no different to weather routing software installed on a competitor´s yacht. The 100km resolution routing is included in the free package of PredictWind, and so complies with rule 41 of the racing rules of sailing

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Support


What kind of support do you offer?

If you have technical issues or questions relating to the forecast or your account, simply use the Red Feedback menu from within your account. Your query will be tracked and answered by email as soon as possible.
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What are the Hardware/Software Requirements?

The PredictWind site can be viewed in the latest version  of

  • Internet Explorer 
  • Mozilla Firefox 
  • Safari 
  • Chrome 

Earlier versions of these browsers are not supported

The minimum screen resolution is 1024*768. If you cannot see all of the maps on your screen, we recommend changing the browser into full screen mode by selecting the F11 key.


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