Projected weather/course app

[largojimbo2003]

Hello,

I know weather can change on a dime, but does anyone know of an app for sailors that can project the weather for a certain course plotted?

Would be great to know the anticipated weather for, lets say, a 10 day sail from NC to FL and update as the towns and days go by so you can plan ducking in after 5 days if need be because of strong storms in the forecast.

Thanks,

Jim

[CarstenWL]

... plenty of software packages for this ...

- qtVlm
- Adrena
- TimeZero
- ...

Or 'integrated into plotters. Search 'yacht routing software' ...

Regards,

Carsten

[Paul L]

Or try the online routing tool
http://www.fastseas.com

[.Paul.]

Originally Posted by largojimbo2003

Hello,

I know weather can change on a dime, but does anyone know of an app for sailors that can project the weather for a certain course plotted?

Would be great to know the anticipated weather for, lets say, a 10 day sail from NC to FL and update as the towns and days go by so you can plan ducking in after 5 days if need be because of strong storms in the forecast.

Thanks,

Jim

OpenCPN and the Weather Routing plugin might be the app you are seeking.

Here is a link to the manual for these
https://opencpn.org/wiki/dokuwiki/do...pn_user_manual

There are yachts using this system for coastwise voyages and for crossing oceans. The weather forecast is in the form of a gridded binary (GRIB) file that is produced by NOAA (or other national or multinational organizations). The GRIB can be downloaded when you have an internet connection or some radio link that can receive the GRIB in an EMAIL.

The GRIB forecasts extend up to 16 days. The first few days are pretty good, but after 5 days the forecasts may not agree with the real world. So you need to be able to get new GRIB weather every few days.

Paul

[unbusted67]

Does anyone use Predict Wind’s Weather routing?

[barnakiel]

qtVlm


e.g.


b.

[belizesailor]

Ive used SailGRIB WR a lot w good results:

https://www.sailgrib.com/

[CassidyNZ]

Originally Posted by unbusted67

Does anyone use Predict Wind’s Weather routing?

Yes, almost exclusively.

[Yellow bird]

Originally Posted by largojimbo2003

Hello,

............................................
Would be great to know the anticipated weather for, lets say, a 10 day sail from NC to FL and update as the towns and days go by so you can plan ducking in after 5 days if need be because of strong storms in the forecast.

Thanks,

Jim

You have to know that weather forecast is very good till the first 72 hours, than you need to update the data otherwise the forecast you have is outdated, and it look like almost a horoscope predictions.
And this is not depending on the app or the program you use, it's depend on the nature of the planet

The most important thing is not what app/program to use, but it's the opportunity to update the data!

[Snore]

Originally Posted by largojimbo2003

Would be great to know the anticipated weather for, lets say, a 10 day sail from NC to FL and update as the towns and days go by so you can plan ducking in after 5 days if need be because of strong storms in the forecast.

For most of that run you should be in range to get NOAA weather on the VHF.

[barnakiel]

I think anybody intending to use wx data and routening / forecasting Apps wants to run this mental exercise:


A) It is Monday and you download wx data.


This data is already old (!!!) if you download forecast data. Because any forecast uses ex data and the software needs some time for processing. Even IF you have access to observed data, it is also 'old'.



Let's assume this near RT data is 6 hours 'old'.


B) You set off with a (low level) AI created assumption of what the weather is and what it will be in the future.


One look outside of the cabin, however, tells you exactly what the actual, not virtual, RT weather is doing and from this you can infer another 30 minutes or 1 hour of what is coming.


C) If you assume 24hrs forecast to be 75% probable, then your 72hrs forecast is roughly 50% probable. This is to say it may rain or not rain and the wind may be 10kts from E or 25kts from W. NOT MUCH USEFUL.


Conclusions:


- look up from that blinking screen every 30 minutes and make your sailing decisions based on WHAT YOU SEE, not on ex assumptions made by mathematical models based on ex data,


- when you download wx data and use wx Apps: download new data in regular periods, more often is better, every 6 hrs is minimum in dynamic areas, 12 or 24hrs may be enough in regular areas in their fine wx periods,


- in cases of discrepancy between what you see on the water and what you see on the screen, act in line with what the weather is doing, NOT in line with what that App says.


In rare cases (extreme sports like climbing or ocean races) decisions are made based on what the weather is digitally assumed to be doing soon. But this is by extreme athletes backed by wx analysts. For money, for fame, or for more noble reasons (e.g. SAR operations)) DO NOT try to emulate this attitude - it is not for you, if you are a plain sailor with a smartphone.


Have an App and enjoy it but be very aware of the pitfalls and limitations.


Assume reality is real. The other thing is a digital guess.


Hope this helps someone.


Cheers,
b.

[belizesailor]

Originally Posted by barnakiel

I think anybody intending to use wx data and routening / forecasting Apps wants to run this mental exercise:


A) It is Monday and you download wx data.


This data is already old (!!!) if you download forecast data. Because any forecast uses ex data and the software needs some time for processing. Even IF you have access to observed data, it is also 'old'.



Let's assume this near RT data is 6 hours 'old'.


B) You set off with a (low level) AI created assumption of what the weather is and what it will be in the future.


One look outside of the cabin, however, tells you exactly what the actual, not virtual, RT weather is doing and from this you can infer another 30 minutes or 1 hour of what is coming.


C) If you assume 24hrs forecast to be 75% probable, then your 72hrs forecast is roughly 50% probable. This is to say it may rain or not rain and the wind may be 10kts from E or 25kts from W. NOT MUCH USEFUL.


Conclusions:


- look up from that blinking screen every 30 minutes and make your sailing decisions based on WHAT YOU SEE, not on ex assumptions made by mathematical models based on ex data,


- when you download wx data and use wx Apps: download new data in regular periods, more often is better, every 6 hrs is minimum in dynamic areas, 12 or 24hrs may be enough in regular areas in their fine wx periods,


- in cases of discrepancy between what you see on the water and what you see on the screen, act in line with what the weather is doing, NOT in line with what that App says.


In rare cases (extreme sports like climbing or ocean races) decisions are made based on what the weather is digitally assumed to be doing soon. But this is by extreme athletes backed by wx analysts. For money, for fame, or for more noble reasons (e.g. SAR operations)) DO NOT try to emulate this attitude - it is not for you, if you are a plain sailor with a smartphone.


Have an App and enjoy it but be very aware of the pitfalls and limitations.


Assume reality is real. The other thing is a digital guess.


Hope this helps someone.


Cheers,
b.

True, relying only on models (or just one as many do) without experienced interpretation is a good way to get your butt kicked.

Like the Bowditch adage about navigation...a good weather router never uses just one source of information.

Example: I crewed on an Atlantic crossing earlier this year. I was responsible for weather routing. I used all sources I had access to (multiple models, NOAA forecast charts, etc) plus engaged Chris Parker's services. I did my homework each day and then discussed via SSB with Chris. I used every reasonable resource at my disposal to ensure we achieved our goal of a safe, comfortable, uneventful crossing, not a record, we were highly successful.

[Paul L]

The biggest use and advantage I've had with weather routing programs is in planning what day to start a passage. This is useful in passage latitudes and areas where the weather is actually variable. I run the routing for the following week starting at the same time each day. Then look at the predicted info on each routing for motoring time, beating and close reaching time, max wind ahead of the beam, and passage time. I rerun these each day till we choose to leave.
On passage a simple GRIB file daily and our own observations has worked well so far.

As far as onshore weather routers. These are a real mixed bag. The only time we really used one, it was a freebie with a rally. The advice to leave and the first 36 hrs was dangerously wrong with many boats suffering damage and multiple maydays. The following next 6 or 7 days was nothing like predicted either. This was Chris Parker.

I've had other boats relay me their onshore routers suggestions while on passage. They often seem to stick to a conservative plan that was ceeated prior to passage, rather than changing plan to effectively use what is actually happening. I was even on one passage where another boat was getting onshore routing from 3 routers. Talk about confused.
In areas where the weather is very localized and there are local routers their advice can certainly be very helpful, such as the islands to New Zealand run.

[belizesailor]

Originally Posted by Paul L

...
As far as onshore weather routers. These are a real mixed bag. The only time we really used one, it was a freebie with a rally. The advice to leave and the first 36 hrs was dangerously wrong with many boats suffering damage and multiple maydays. The following next 6 or 7 days was nothing like predicted either. This was Chris Parker.

...

Cant get it right all the time, but Chris is damn good. When and where did that happen?

[Paul L]

Originally Posted by belizesailor

Cant get it right all the time, but Chris is damn good. When and where did that happen?

Yep, seems like a good forecaster is anything >=50% correct.
This was 2013 or 2014 Virginia to the BVIs.