Predictwind.com

[roaringgirl]

I am currently weather routing a friend across the Atlantic. I have done this several time for people and used a variety of sat devices to do it. The iridium sat phone messaging services is rubbish. Very slow to use. By comparison the Garmin Inreach is a pleasure. We know several people who have ditched to sat phone in favour of text only sat device. Cheaper to operate and easy to use. The best weather info you can get at sea in my opinion is a competent person with a good internet connection, access to several weather models and a text only connection to you. The guy at home has had a good night's sleep is looking at weather in as much detail as needed and can advise accordingly

I beg to differ: which models are you looking at to do your routing? - the unlimited data subscription over iridiumGO offered by PW means you can download PWE, PWG, GFS, ECMWF, SPIRE and UKMO data in as much detail as they are published. The resumable tx/rx data transfer makes the process far more useable than data-over-satphone and you can also communicate via sms and email to discuss routing options with land-based friends.

 

[geem]

I beg to differ: which models are you looking at to do your routing? - the unlimited data subscription over iridiumGO offered by PW means you can download PWE, PWG, GFS, ECMWF, SPIRE and UKMO data in as much detail as they are published. The resumable tx/rx data transfer makes the process far more useable than data-over-satphone and you can also communicate via sms and email to discuss routing options with land-based friends.

When it works. The iridium Go has a reliability problem. The Salty Dog rally a few years back recommended that if you were using a Go you should carry an Inreach as a back up.
We have a few friends who have had failures. They cost twice the price of an Inreach to buy and the unlimited subscription is more than twice as much. I think when they work they can be good but at a price. We don't spend a lot of time crossing oceans in the scale of things to the Inreach does it for us. Once we get to land we buy a local SIM and have fast internet connection something the Go can't do

 

[roaringgirl]

When it works. The iridium Go has a reliability problem. The Salty Dog rally a few years back recommended that if you were using a Go you should carry an Inreach as a back up.
We have a few friends who have had failures. They cost twice the price of an Inreach to buy and the unlimited subscription is more than twice as much. I think when they work they can be good but at a price. We don't spend a lot of time crossing oceans in the scale of things to the Inreach does it for us. Once we get to land we buy a local SIM and have fast internet connection something the Go can't do

I am not aware of reliability issues with the GO, please expand on this.

 

[franksingleton]

PW over IridiumGO gives you grib information from 6 models (ECMWF, GFS etc...) and a means of displaying it, and weather routing based on those models and the parameters you enter for you boat's performance and your sailing preferences, should you wish. The PW app will also accept and display raw grib files, if you want to obtain them via email and the IridiumGO can send and receive emails, so you could get raw gribs and display them on whatever app you wanted to, were there some reason you didn't like PW's display.

Thank you again, all. The various comments are interesting to me. As you know, I am a meteorologist and a (mainly) coastal sailor. I probably have a better understanding than most of the limitations to weather prediction. As a result, I am always more than a little concerned when I see claims of high precision and accuracy in forecasts. That applies to most, third party providers whether of free or prepayment services. I have yet to find anyone who warns of the effective resolution issue._

I have just written a book in the Adlard Coles Cockpit Guide series. It is orientated towards coastal and short sea passage making types of sailor mor than the more experienced types in this thread although, obviously, I hope that most will learn something . I have 3 or4 short paras on routing. I start by saying that a newcomer to blue water sailing might like to use a professional router who will use judgement and experience. I then suggest three options. First, is to use a shore based routing firm and the only one I quote is PW. Second is more of a DIY service based on SailGrib or similar. Third, a little tongue in cheek was based on discussion with a winning RTW Volvo winning navigator. His view was that in his slow 40 footer, he would wait until he had a weather window to get well clear of land then, take what came using forecasts to know when to prepare vessel and crew for bad weather. That, really, was based on the thought that most yachts are too slow, major storms are so big and prediction beyond a week so difficult, that blind use of routing could lead you into trouble as easily as taking my RTW contact’s advice.
All, of course, assuming that the planned route is sensible, climatologically.
My direct experience of routing dares back to when the Met Office had a ship routing service. Some of the ships were only capable of 10 kts or so,

 

[roaringgirl]

Thank you again, all. The various comments are interesting to me. As you know, I am a meteorologist and a (mainly) coastal sailor. I probably have a better understanding than most of the limitations to weather prediction. As a result, I am always more than a little concerned when I see claims of high precision and accuracy in forecasts. That applies to most, third party providers whether of free or prepayment services. I have yet to find anyone who warns of the effective resolution issue._

I have just written a book in the Adlard Coles Cockpit Guide series. It is orientated towards coastal and short sea passage making types of sailor mor than the more experienced types in this thread although, obviously, I hope that most will learn something . I have 3 or4 short paras on routing. I start by saying that a newcomer to blue water sailing might like to use a professional router who will use judgement and experience. I then suggest three options. First, is to use a shore based routing firm and the only one I quote is PW. Second is more of a DIY service based on SailGrib or similar. Third, a little tongue in cheek was based on discussion with a winning RTW Volvo winning navigator. His view was that in his slow 40 footer, he would wait until he had a weather window to get well clear of land then, take what came using forecasts to know when to prepare vessel and crew for bad weather. That, really, was based on the thought that most yachts are too slow, major storms are so big and prediction beyond a week so difficult, that blind use of routing could lead you into trouble as easily as taking my RTW contact’s advice.
All, of course, assuming that the planned route is sensible, climatologically.
My direct experience of routing dares back to when the Met Office had a ship routing service. Some of the ships were only capable of 10 kts or so,

In my experience it's really important to try all these things well before departure. At zero cost, it's possible to get a good idea of how PW works and what it gives you.

 

[franksingleton]

An afterthought, back to someone mentioning PWG/E. That model uses a 50km. Grid length. As I said, somewhere above, the major determinant of model performance is grid length. ECMWF and Met Office use a 9 or 10 km grid. The others us 13 km. Forget PWG/E.

 

[Ademist]

We used email over an Iridium satphone to get our forecasts across the Atlantic. It was extremely time consuming for me and expensive in terms of satphone minutes consumed. Sometimes we had to give up with nothing recieved even though tens of precious data minutes were spent in the attempt. This is because with data on an Iridium *phone* the tx/rx is not resumable so if the signal drops mid-transfer the email is lost and the transfer has to be restarted. On one particular occasion, we had to give up trying to get a forecast; we were then caught with our sails up in a squall with a max recorded speed of 55kts that resulted in a knockdown and a broken spinnaker pole - the loss of which severely impeded our progress for the rest of the crossing (10 days). The following day when we finally succeeded in getting our forecast emails, they included a warning about the very severe squall.

This is not our experience. We use sailmail on an iridium extreme handset , via an external antenna, to download weather forecasts when we aren’t able to get them via SSB radio and Pactor modem. Using the sail mail facility to download forecasts on the irridium extreme has proved extremely reliable and uses a minute or two of data minutes per download.

It maybe that I am downloading smaller area grib files than you, over fewer days, but I generally give a wide margin for our proposed route and look forward 5 days. It maybe that the sailmail forecast software is the difference.

 

[roaringgirl]

This is not our experience. We use sailmail on an iridium extreme handset , via an external antenna, to download weather forecasts when we aren’t able to get them via SSB radio and Pactor modem. Using the sail mail facility to download forecasts on the irridium extreme has proved extremely reliable and uses a minute or two of data minutes per download.

It maybe that I am downloading smaller area grib files than you, over fewer days, but I generally give a wide margin for our proposed route and look forward 5 days. It maybe that the sailmail forecast software is the difference.

The thing that's being downloaded in each case is a grib file. The software that's used to view it is irrelevant. One trouble-free user doesn't prove that the product is trouble-free, but one user experiencing problems proves their existence.

 

[roaringgirl]

I am not aware of reliability issues with the GO, please expand on this.

I'm about to head offshore across the Pacific with my young family and will be relying on the IridiumGO for forecasts and communication with the outside world. If there's a reliability issue with the GO, I need to know about it, so please provide more info.

 

[Ademist]

The thing that's being downloaded in each case is a grib file. The software that's used to view it is irrelevant. One trouble-free user doesn't prove that the product is trouble-free, but one user experiencing problems proves their existence.

I was perhaps not crystal clear, but I intended to refer to the sailmail transmission and downloading software as possibly making the difference, not the viewing software, which is irrelevant.
I agree you exist.

 

[Ademist]

I'm about to head offshore across the Pacific with my young family and will be relying on the IridiumGO for forecasts and communication with the outside world. If there's a reliability issue with the GO, I need to know about it, so please provide more info.

You’ll have a fabulous time .

Several friends who crossed when we did 3 years ago used irridium Go and managed with it. We didn’t hear of significant issues apart from one , very speed orientated boat, where they found slow download speeds and some cutouts when downloading predictwind to the B&G chart plotter for route forecasting. I suspect they were downloading huge files in order to do detailed route planning.

As always with ocean crossing, a backup plan is a good idea. Other boats, SSB, connection via handset are all possible.

 

[franksingleton]

This is not our experience. We use sailmail on an iridium extreme handset , via an external antenna, to download weather forecasts when we aren’t able to get them via SSB radio and Pactor modem. Using the sail mail facility to download forecasts on the irridium extreme has proved extremely reliable and uses a minute or two of data minutes per download.

It maybe that I am downloading smaller area grib files than you, over fewer days, but I generally give a wide margin for our proposed route and look forward 5 days. It maybe that the sailmail forecast software is the difference.

I hope that you will not think me to be cones ending when I say that you are getting it right. I think that there may be some misunderstanding by users in confusing data volume with information content. You may be able to get ECMWF data with a 0.e1 deg resolution but will get no more information than getting it with 0.2 degree res. Remember that models have smoothing to about 5 grid lengths. The important factor is the grid length used by the model. Shorter is better. But in terms of usefulness, there is no point in downloading at the model resolution. Obviously, the same applies to time steps. Six hourly for an ocean crossing is probably as short as you need, maybe even 12.

 

[Sandy]

Is anyone using the paid for version of this.

I attended the two webinars that they ran in 2020 or 21. It was more a hard sales pitch than anything useful. Talk about blowing your own trumpet these guys were so hyped up they sounded like an American Marching Band at the Superbowl, but I am a cynical Scots retired engineer who is technically savvy and has an interest in weather.

I took them up on their offer of a free months subscription as I was interested in the routing functionality. After several days playing with it I packed it away and don't plan to use the paid for version in the future.

 

[franksingleton]

I attended the two webinars that they ran in 2020 or 21. It was more a hard sales pitch than anything useful. Talk about blowing your own trumpet these guys were so hyped up they sounded like an American Marching Band at the Superbowl, but I am a cynical Scots retired engineer who is technically savvy and has an interest in weather.

I took them up on their offer of a free months subscription as I was interested in the routing functionality. After several days playing with it I packed it away and don't plan to use the paid for version in the future.

Sandy, you are quite right to be cynical. I have watched this video several times to make sure that I really did hear correctly.

The Spire man was abysmal. In describing observing networks, he was very economical with the truth and made at least one incorrect statement. When it came to describing their forecast results, he mis-quoted both ECMWF and the Met Office.
The Spire write up. https://predictwind.intercom-attach...65/f695bf0a58167c3c2e72510c/Spire+Stratos.pdf, on the PW site has a diagram that is at total variance with similar data presented by ECMWF. I pointed a former colleague at this. His only comment was to hope that they would publish their findings for peer review.
Both PW and Spire make claims about Radio Occultation that are not true.. PW says that Spire are using a “unique technique of measuring the earth’s atmosphere.” In fact, RO has been used since 2007. A Met Office study in 2020 showed that Spire RO dara were of comparable quality to existing RO data. There is no doubt that Spire does produce good RO data and these will be incorporated into ECMWF models later this month and, presumably, Met Office also. They could increase the volume of RO data by 100%. The increase in % contribution of RO data (or any other data type) increases in proportion to the log of the % data increase. ECMWF use of Spire data for 3 months in 2o20 showed that that currently, RO data contribute roughly 10% of the total input of all data types. Adding Spire RO data could increase that contribution to 14%.
RO data are certainly valuable. They are particularly good in the upper atmosphere/lower stratosphere where they act as an anchor enabling better use of the many millions of other bits of data. But, like all satellite tempersture and humidity soundings, they do not, in fact, measure either. RO data provide bending angles of radio signals. No more and no less. There are limitations to the data, particularly in the mid troposphere.
If anyone is interested, I can itemise the many shortcomings in the video. There are too many to discuss here.
Beware Greeks bearing gifts?

 

[Buck Turgidson]

Sandy, you are quite right to be cynical. I have watched this video several times to make sure that I really did hear correctly.

The Spire man was abysmal. In describing observing networks, he was very economical with the truth and made at least one incorrect statement. When it came to describing their forecast results, he mis-quoted both ECMWF and the Met Office.
The Spire write up. https://predictwind.intercom-attach...65/f695bf0a58167c3c2e72510c/Spire+Stratos.pdf, on the PW site has a diagram that is at total variance with similar data presented by ECMWF. I pointed a former colleague at this. His only comment was to hope that they would publish their findings for peer review.
Both PW and Spire make claims about Radio Occultation that are not true.. PW says that Spire are using a “unique technique of measuring the earth’s atmosphere.” In fact, RO has been used since 2007. A Met Office study in 2020 showed that Spire RO dara were of comparable quality to existing RO data. There is no doubt that Spire does produce good RO data and these will be incorporated into ECMWF models later this month and, presumably, Met Office also. They could increase the volume of RO data by 100%. The increase in % contribution of RO data (or any other data type) increases in proportion to the log of the % data increase. ECMWF use of Spire data for 3 months in 2o20 showed that that currently, RO data contribute roughly 10% of the total input of all data types. Adding Spire RO data could increase that contribution to 14%.
RO data are certainly valuable. They are particularly good in the upper atmosphere/lower stratosphere where they act as an anchor enabling better use of the many millions of other bits of data. But, like all satellite tempersture and humidity soundings, they do not, in fact, measure either. RO data provide bending angles of radio signals. No more and no less. There are limitations to the data, particularly in the mid troposphere.
If anyone is interested, I can itemise the many shortcomings in the video. There are too many to discuss here.
Beware Greeks bearing gifts?

And their competitors.

 

[franksingleton]

And their competitors.

There are few commercial competitors. I have had no contact with anyone using Squid and minimal with LuckGrib users.
The MPAS model used by Spire is a NCAR/UCAR model provided for testing and model development. I am not saying that Spire forecasts are not good. They use MPAS with a 13 km grid. As far as I know, the MPAS model is always run with55 levels. I am not sure about the lid but I think it is 30 km . GFS, ICON etc have around 100 to 130 levels and lids at 80 km. The Spire MPAS might well give as good forecasts but is unlikely to be better.
PW are aggressive marketeers. I am not saying that their forecast services are not good. I am saying that they issue ECMWF, GFS, UK UM. They do not provide ICON, ARPEGE or CMC GEM. From what I have heard here and elsewhere, their delivery services are good. I have to wonder why they claim to provide better forecasts than anyone else. I object to their claims to being the world leader in wind forecasting. They provide information from world leading models. They are users, not modellers.

 

[MathiasW]

I'm about to head offshore across the Pacific with my young family and will be relying on the IridiumGO for forecasts and communication with the outside world. If there's a reliability issue with the GO, I need to know about it, so please provide more info.

I do not have a GO, but a friend of mine who does installations on vessels mentioned to me a few years back that GO has a connector from big to fiddly which often is a breaking point. So, as long as you keep it mechanically stable, that particular issue should not be a problem.

When you use GO also for emergency phone calls, my understanding is that you need to do that via a mobile phone. Make sure all crew members have this enabled. During ARC+2019 there was one fatality, and when the crew tried to call for help, it turned out the only phone connected to the GO was the skipper's one, and he was dead. Nobody else had his pin number... It was so sad. I had met that sailor only days before and had admired him for his fitness.