Marine Weather Forecasting

[sinbad7]

Chala..

Forecasts Using FTP

This is a useful service for those who do not want to use web page links to forecasts - for example when using mobile or satellite phones or INMARSAT-C. In fact, anyone with limited bandwidth

Text messages of forecasts that are broadcast on VHF and other channels as part of the Global Maritime Distress and Safety System can be obtained over the Internet using the links on the GMDSS or other pages of this site. This is fine if you have Internet access. However, at sea, with HF/SSB radio, INMARSAT-C or Mini-C, for example, it may be feasible only to send and receive emails. Even within mobile phone range access to websites can be slow.
In such cases, the NWS (Washington) FTP Mail Service could well be useful. For full details go to the FTP link page on Martin Stubbs' site.Briefly, you simply send a message in a strict format, copied from Martin's page. Within minutes the reply comes back as an email. This is a free service and the only costs will be for the email links. Charts can also be obtained in the same manner. These come in TIFF format; files are likely to be some 70 kB and to receive them might be expensive, but useful on occasions when other communications have failed.

[barnakiel]

Originally Posted by John A

I believe that here are at least five computer modeling services for the Caribbean alone. Each analysis is the result of the provided input subject to the whims of the programs written. These differences can be noted in the wide range of tracking forecast for Hurricans.

GRIBS and hurricane tracks' forecasting should be viewed separately, even though in fact they both use mathematical modeling.

There are no whims, so to say - the mathematical models are one thing, the real life another. Often the prediction is spot on, but the longer the horizon, the more variation is expected from the nature of the tool. One has to see this and allow for it in their use of all and any navigation / wetaher forecasting / etc tools.

I use GRIBS for weather routing and all boats I worked for have been perfectly happy with results. Of course, GRIBS are only one of many sources, and NOT the only one. But actually, if GRIBS agree with other sources then the routing suggestions are made by a dedicated software working on GRIBS and polar diagrams of the boat.

BTW Now want to find the way to incorporate digitized wave fcst info into my work. Does anybody know if the new functionality tested (so successfully) by Foncia will be available commercially any time soon? (I mean using wave forecast data in weather routing tools)?

barnie

[Paul Elliott]

Originally Posted by chala

The problem with Email based grib files here in Oz is that email can not be accessed with an Iridium satellite phone. All the Internet Services Provider that I have tried do not allow the relaying of mail. Email would be the fastest and cheapest way of getting grib file because the writting can be done offline. I presently use Ugrib and I am trying to find how accurate grib file are.

I use my Iridium satphone for grib email, and it works well. I use GMN (Global Marine Networks) XGate for my service provider, and using this account send the grib requests to saildocs. XGate provides a web email interface so you can set up and test your grib subscriptions when you have internet access.

Note that with Saildocs you can also request compressed wfax forecast charts. I usually get the surface charts for current, 24, and 48 hour forecasts, and the grib with surface pressure, surface wind, and waves.

GMN also has a subscription-based grib and wxchart delivery product that looks good, but I've been happy with the free stuff from Saildocs.

I've used this Iridium system between the USA west coast and Hawaii, and in the South Pacific, with good results.

[btrayfors]

I much prefer the forecasts such as found on PassageWeather.com, like these wind and surface pressure ones for this coming Saturday off the Brazilian coast:





These are about 20kb each. Or, you can download a zip file containing all 30 images for wind (about 500kb).

Bill

[chala]

Originally Posted by Paul Elliott

I use my Iridium satphone for grib email, and it works well. I use GMN (Global Marine Networks) XGate for my service provider, and using this account send the grib requests to saildocs. XGate provides a web email interface so you can set up and test your grib subscriptions when you have internet access.

Hello Paul, I have read many of your posts on Iridium on this and other forums.
I would assume that GMN is not a free service and may not be available in OZ.
The cost of receiving a small 3 days Ugrib (17 to 32 kbs) is around $5.00 Oz and could be cheaper if not queed or having to produce a username. If it was necessary to paid for a subscription this will ad to the cost.
Receiving Email is as fast than an ordinary Dial-up and I would say that Ugrib information are superior to Saildocs.
I have tried USA based ISP but here in OZ they seems to have been Australianized and have the same problem. The fact that ISP do not allow relaying of mail may be unlawfull, because in fact they are restricting informations, secondly they open themself to huge compensation claims if by not allowing the relaying of vital information they contribute to the death of a person.

[chala]

Originally Posted by sinbad7

In such cases, the NWS (Washington) FTP Mail Service could well be useful. For full details go to the FTP link page on Martin Stubbs' site.Briefly, you simply send a message in a strict format, copied from Martin's page. Within minutes the reply comes back as an email. This is a free service and the only costs will be for the email links. Charts can also be obtained in the same manner. These come in TIFF format; files are likely to be some 70 kB and to receive them might be expensive, but useful on occasions when other communications have failed.

Sinbad7
Thank you for the information.
I will have a go at it and report.

[bewitched]

I've been usuing UGRIB for around two years now. I've found it very good for the "big picture" forecast and trending (e.g. wind speed increasing over next few days, wind veering etc).

What I have noticed though is that identification and forcasting of typhoons is often very poor.

[chala]

Originally Posted by bewitched

I've been usuing UGRIB for around two years now. I've found it very good for the "big picture" forecast and trending (e.g. wind speed increasing over next few days, wind veering etc).

What I have noticed though is that identification and forcasting of typhoons is often very poor.

The big wind that hit Brisbane by surprise few month ago were accurately forecasted by Ugrib 3 days before the so-called surprise.

The grib files produced by saildocs (the quickest, but not available with Iridium), Ugrib (the more versatile) and the local Bureau of Meteorology (does not cover with detail the place of interest, the sea to the north of Melville island), seem to correlate. I wonder if they come from the same Met computer.

I am not sure if I can get the same type of information through ftpmail@ftpmail.nws.noaa.gov.

[sailing mike]

Hi Bernard,
Would you know anyone who is runing Linpus Linux (Fedora), and has conpiled ZYGrib for it. I'm a Linux newbe and so I'm not confident about compiling sorce code. I have read the instructions but....

[sinbad7]

Ref my #5 about ExpeditionLT

ExpeditionLT makes use of the very accurate,local wind/weather forecast from Predictwind.com. This is a subscription GRIB service starting from $15.- per month
but gives very detailed forecasts down to 1 nm.

The combination Expedition/Predictwind has been used in most of the large sailing races and you can read the recommendations here:

You can also download less accurate GRIB files covering wider areas using the free UGRIB program which stores the GRIB files on your hard disk for later retrieval with your favourite GRIB browser including the free ExpeditionLT. Or,you can use Fugawi Marine ENC,MaxSea and similar programs. If I'm not mistaken,I also think Dave has some surprizes for us shortly.

[barnakiel]

Originally Posted by sinbad7

Ref my #5 about ExpeditionLT

ExpeditionLT makes use of the very accurate,local wind/weather forecast from Predictwind.com....... gives very detailed forecasts down to 1 nm.

1) The 1' accuracy does not count much against the inaccuracy of the wind speed/dir there is, does it.

2) Is their (predictwind.com) model a 1' resolution one or is it an interpolation from publicly available 30' resolution? I beleive it is an interpolation that will just inflate the file.

b.

[sinbad7]

REF. #5 ExpeditionLT

The software is used extensively in ocean racing and judging by the comments from the professionals,it seems to do the job.

PredictWind uses two data sources for the wind weather model, to produce two alternative marine weather forecasts for comparison. The closer the wind forecast, the more confidence you can have in the PredictWind wind forecast.

[Jmolan]

Sinbad7,
I wanted to thank you for the great thread. This was a subject I was very interested in. I am both a professional mariner and a pleasure boat guy. I have this thread book marked.
The fleet I work with in the Bering Sea are still using weather fax data over a sideband set up. It is less than reliable. That, and voice forecasts, which are quite good.
I hope to be making a passage soon in my 34' Trimaran. There are various "nets" of course that you can use for weather planning.

[sinbad7]

JMolan..

Fascinating pics.. you certainly know your ropes..

I have often watched the Bering Strait crabbers on their daring sweeps,her on Brazilian TV.

I am participant in a world wide AIS network and now, as a pensioner,follow old friends and vessels on their voyages across the seas from my armchair in Costa Verde. We used to have a receiver also in Unalaska but haven't seen any traffic from them for a while.

[barnakiel]

Originally Posted by sinbad7

...The closer the wind forecast, the more confidence you can have in the PredictWind wind forecast...

And PredictWind is not unique in this respect.

;-)
b.