steeds
New Member
I use a wet vax on blow, mega fast!
The ups and downs of being a Sailor.
- Thread starter capnsensible
- Start date
franksingleton
Well-Known Member
Thanks. That is as it always has been. My criticism of all “non-official” detailed forecasts is how the get their initial analysis. Whenever I ask, those who reply always admit that they use the GFS 25 km output and interpolate. The “professionals” use massive amounts of satellite and radar data combined with in situ observations. This is a 4-D data fitting exercise. There is a certain amount of subjectivity or trial and error involved in weighing the different data types. How critical it is for sailing purposes, I am not sure. Small details have short lifetimes and tha limits predictability. A feature of about 30 km size has a lifetime of around 6 hours from data time. By the time that you are using the forecast, anything that size or smaller Will have died. But, my main beef about the commercial modellers is that some of them claim great accuracies that are unobtainable.
what the forget, ignore or just do not know is that a NWP model effective resolution is about 5 grid lengths. Detail smaller than that has to be filtered out - if not, the computations produce nonsense.
My usual advice is to use whichever model you receive in a way and presentation thst you like but do not think that it is superior to others. I may look at limited area forecasts out of interest but make all my decisions using global models +GMDSS texts + native wit.
franksingleton
Well-Known Member
Thanks, I had not seen that one, it is since my time in that area. As you know, his chart is from Windy.com, probably the ECMWF global model. Apart from it only being updating twice a day and running about 2 hours later than operational models, that should be as good as anything. The Spanish AEMet detailed model should, in theory, do better but in practice .....I really dont need massive detail for the sailing I do here in the Canaries. Windfinder does it for me.
A good resource for the Straits of Gibraltar, IMO is Steph Ball at MeteoGib. The website forecast is basic but if you need a bespoke forecast and advice, for a small fee, she is a true expert on the area. When I was a bit time constrained with sailing school courses, she was brill at helping with passage planning.
gibraltar webcam weather
Gibraltar is probably one of those few places where local informed meteorological knowledge can do better than objective models. In most areas, winds usually decrease overnight due to cooling of the surface. Around the rock, the reverse can occur. Unless you have experienced it, sea fog can be a surprise.
capnsensible
Well-Known Member
Although we've moved on, I still reckon its one pf the best areas for learning to sail. Its got a great variety of conditions and loadsa traffic, as you know! Fascinating how weather develops and as you say, the fog can give some interesting navigation problems.
When we were first there, the MOD Met Office at the airport used to give a very good sailors forecast mid morning on the Services Radio Station, BFBS. Gone now..... You could also ring the duty forecaster for information about the Straits as a free service. Gone too, sadly. Still used to see the weather balloon going aloft at midday though!
Over the years I could have a fair go at understanding what was gonna happen around the rock, but for trips out to the west through the Straits, a call to Stephanie was always worth it.
