dunedin
Well-Known Member
+1. Video very difficult to access in many locations
Re OP question, over past 6 months have used xcweather - and in UK seems to be more accurate short term than Inshore Waters in my experience
Best resource for inshore weather for a week or so ahead?
- Thread starter steve yates
- Start date
+1. Video very difficult to access in many locations
Re OP question, over past 6 months have used xcweather - and in UK seems to be more accurate short term than Inshore Waters in my experience
Babylon
Well-Known Member
Another forecast source, which I use along with XC Weather for inland forecasts is metoblue but they do also cater for coastal areas, to which they add something of sea-related data:
https://www.meteoblue.com/en/weather/forecast/week/hamble_united-kingdom_2647585?day=3
I use these two especially for my other distraction of radio-controlled thermal soaring, and particularly like the relative 'confidence' they give to each day's forecast, and present the 'multi-model' data from all forecast models for up to six or seven days ahead:
https://www.meteoblue.com/en/weather/forecast/multimodel/hamble_united-kingdom_2647585
https://www.meteoblue.com/en/weather/forecast/week/hamble_united-kingdom_2647585?day=3
I use these two especially for my other distraction of radio-controlled thermal soaring, and particularly like the relative 'confidence' they give to each day's forecast, and present the 'multi-model' data from all forecast models for up to six or seven days ahead:
https://www.meteoblue.com/en/weather/forecast/multimodel/hamble_united-kingdom_2647585
Yngmar
Well-Known Member
+2 (Météo Consult) - They have a nice iPhone app. Also, there are local readings for most marinas/harbours, in addition to the coastal areas.
franksingleton
Well-Known Member
This kind of enquiry has come up many times. I have said on several occasions that which GRIB or GRIB derived product you use depends on ease of access to you and ease of use – again to you. The basic data are the same. As ever with meteorology there are caveats. In this case, there can be short-lived differences due to precise update times.
The U.S. GFS, the basis for virtually all these services is remarkably good. We can see quite short weather windows several days, 5 or 6 ahead. Almost uncanny at times
We prefer to use zyGrib not because it is a better forecast but for several practical reasons.
• I can choose my own area of interest – currently Scillies across all of Biscay.
• I can select up to 10 days ahead, with intervals from 3 hours and grid spacing down to 0.25 degree. NOTE these are not interpolated but model grid point values. The GFS calculates on a 0.125 degree grid and provides data on a 0.25 degree grid.
• I can choose which elements I want to download including sea state and, even, high level winds.
• I can view on a grid or select any point and get a time sequence.
• I can download directly even with low bandwidth that will not support a browser – recently my situation in France.
• With no WiFi, I can use email to get the same data and view it in zyGrib
• The data are saved automatically. When SWMBO asks “What did you say for Camaret to Audierne tomorrow?” I can always tell or show her.
Sites such as XCWeather, WindGuru, Passageweather etc are equally as good but with much less flexibility. A plethora of tablet apps do much the same as zyGrib but, again. With a little less flexibility.
If limited area models are available I am happy to look at them – if they are free. I would not pay for any. I have a listing of many, certainly not all, GRIB or GRIB derived services at http://weather.mailasail.com/Franks-Weather/Grib-And-Objective-Forecasts-Reviewed.
For planning purposes, the GFS in whatever guise will not be bettered. For today, ALWAYS heed the GMDSS (VHF, NAVTEX) forecasts. If you feel a need for advice, then go to a forecast service that uses human intelligence. Simon is in the forefront here.
The U.S. GFS, the basis for virtually all these services is remarkably good. We can see quite short weather windows several days, 5 or 6 ahead. Almost uncanny at times
We prefer to use zyGrib not because it is a better forecast but for several practical reasons.
• I can choose my own area of interest – currently Scillies across all of Biscay.
• I can select up to 10 days ahead, with intervals from 3 hours and grid spacing down to 0.25 degree. NOTE these are not interpolated but model grid point values. The GFS calculates on a 0.125 degree grid and provides data on a 0.25 degree grid.
• I can choose which elements I want to download including sea state and, even, high level winds.
• I can view on a grid or select any point and get a time sequence.
• I can download directly even with low bandwidth that will not support a browser – recently my situation in France.
• With no WiFi, I can use email to get the same data and view it in zyGrib
• The data are saved automatically. When SWMBO asks “What did you say for Camaret to Audierne tomorrow?” I can always tell or show her.
Sites such as XCWeather, WindGuru, Passageweather etc are equally as good but with much less flexibility. A plethora of tablet apps do much the same as zyGrib but, again. With a little less flexibility.
If limited area models are available I am happy to look at them – if they are free. I would not pay for any. I have a listing of many, certainly not all, GRIB or GRIB derived services at http://weather.mailasail.com/Franks-Weather/Grib-And-Objective-Forecasts-Reviewed.
For planning purposes, the GFS in whatever guise will not be bettered. For today, ALWAYS heed the GMDSS (VHF, NAVTEX) forecasts. If you feel a need for advice, then go to a forecast service that uses human intelligence. Simon is in the forefront here.
OceanSprint
Well-Known Member
Sure you havnt got windguru units set to Beaufort? A feature which i find useful. A big vote for windguru. I kike the simple semi graphical display.
grumpy_o_g
Well-Known Member
One of the joys of being in the RAF was the ability to speak to to the met man whenever you wanted. If I was planning a cross-country flight I could discuss specific concerns, etc. and get a precisely tailored forecast. I know Simon offers this http://www.weatherweb.net/wxwebpersonal.php but I really do miss being able to speak to the forecaster.
franksingleton
Well-Known Member
Regrettably, the idea of a telephone service accessible to all is a pipe dream. The Met Office used to have Weather Centres that provided a free to all telephone service. One problem was that they simply could never cope with busy spells and were overmanned when the weather was quiet. The real killer was cost. The Met office at the time was under the MOD. As financial pressures increased, Air Marshalls would ask why they could not have a new aircraft but the Met Office could run a public service. Guess who won.
The reality is that the concept of a universal talk to a forecaster service is unachievable. Simon can run a limited commercial service within his resources but could not contemplate running a national service to meet all needs even as a commercial operation. How many staff would he need to handle calls from, say, 10% of sailors around the UK on a average weekend – pus all those deciding about hanging out the washing, going on picnics or taking to the mountains?
Even in the RAF, self briefing is (I believe) now the nom. We tried it (unsuccessfully) in the early 60s but it took another 30 years to become a reality.
The reality is that the concept of a universal talk to a forecaster service is unachievable. Simon can run a limited commercial service within his resources but could not contemplate running a national service to meet all needs even as a commercial operation. How many staff would he need to handle calls from, say, 10% of sailors around the UK on a average weekend – pus all those deciding about hanging out the washing, going on picnics or taking to the mountains?
Even in the RAF, self briefing is (I believe) now the nom. We tried it (unsuccessfully) in the early 60s but it took another 30 years to become a reality.
capnsensible
Well-Known Member
We live next to the runway at RAF Gibraltar. The duty forecaster is on BFBS radio at 0815 weekdays and their local forecasts for the next few days are very accurate. Luxury!!!!
JumbleDuck
Well-Known Member
I sailed from Largs to Arran today. Windguru, using the GFS model, told me I should be getting steady 10kt winds from the south. What I actually got was 8kt from the north, becoming 24kt from the east. Now 10kt from the east. Hasn't been southerly all day.
The midday inshore waters forecast says "Southerly or southeasterly 5 or 6, occasionally 7 at first in North Channel, decreasing 3 or 4." Does the Met Office worry at all when reports from, say, Prestwick flatly contradict what they are predicting?
franksingleton
Well-Known Member
That Inshore forecast sounds as good as it can be bearing in mind the complexity of the topography of the atea. It covers Mull of Galloway to Mull of Kintyre including the Firth of Clyde and North Channel. And yes, any forecaster writing such a forecast will look to see what is happening now.
The 0600 run of the GFS gives a fairly constant direction of SE. Without allowing for topographical effects, I would have expected a SE 4-5.
Now for my own story.
We came across Channel on Sept 11. I was looking for a NE through S to SW, not too strong having a wife who had had two cracks in her hip 3 weeks previously.
We had correctly identified suitable weather for passages L’Aberwrac’h to Roscoff, Roscoff to Lezardrieux, Leazardrieux to St Cast and St Cast to St Peter Port. This last had been a broad reach, top end of F5, one reef.
Several days earlier ,I had settled on, effectively, a one day window for the passage to Dartmouth. If that had closed, we would have been in St Peter Port for another week We did not want that.
On the evening before and on the day, the UK and French shipping forecasts both said SE becoming S 4 or 5. The GRIBs were similar with a hint of a 6. Having a competent granddaughter on board I decided to go hoping to avoid a 6. But being prepared to put in a couple of reefs if necessary.
In the event, we started with the top end of a SE 4 and mutterings of “What about a reef”. North of Guernsey it dropped away and we had to motor for about 9 hours. The main excitement was ship dodging.
The point that I am getting round to is that as a planning tool, the GFS was great and had been for most the time we were away (4 months.) But when it comes to detail, ie will we have a 4, 5 or 6, even over fairly open waters, you can only hope for the best, pan for the worst and hope that the worst will not happen.
That may seem defeatist but let me explain. A W F4 up the Channel will occur with pressures, say, 1004 at Southampton and 1008 at St Malo. A lower pressure of 1 hPa, ie 0.1% lower at Southampton will lead to a 5 hPa difference and a F5. A lower pressure there of 2 hPa, 0.2% will lead to a F6. I have often said that the atmosphere does not know itself to within one Beaufort force.
JumbleDuck
Well-Known Member
Bearing in mind that the north channel effectively got a separate forecast which leaves only the Firth of Clyde, I think that N3 - E6 is a bit of miss for a model (not you) predicting SE 4 - 5.
I remember once floating around more-or-lessin sight of Tiree for two days, throughout which (a) the shipping forecast never said less than W4 and (b) Tiree (weather reports from coastal station) never reported more than a zephyr. There seems to be a distinct lack of reality checking.
franksingleton
Well-Known Member
Take a look at the T=0 for the 1200 GFS run. That is the analysis based on midday data. It shows a SE F4 for the area where you were.
I do not question your N3. I do say that, looking at the midday analysis, what you experienced was anomalous. It might be something that a forecaster knowing the area intimately might have predicted. It is not something that could have been covered in the Inshore Waters forecast. That is the reality just as much as we experienced on the crossing to Dartmouth.
With a shipping forecast covering a million sq miles in 330 words, that kind of thing is always possible. I remember last year a passage Lezardrieux to St Peter Port. Météo France Bullétin Cotiere and Jersey Met both aid something like SW 4-5 decreasing 3-4. We had a SW 5-6, touching 7 giving 7+ knots under a reefed head sail only. Guess what, The UK shipping forecast gave better guidance. They said SW 5-6 for sea area Wight.
Babylon
Well-Known Member
Frank
Great vignette. Your story as a real-world skipper trying to make a real-word passage decision based on an informed analysis of an often highly-sensitive system (ie weather!) is spot on, and this fairly simple but highly-illuminating explanation says it all.
franksingleton
Well-Known Member
Thanks. Perhaps I can give another comment and another example.
When constrained by work, our sailing was often confined to the S coast, Falmouth to Exmouth. This is a relatively simple bit of coast compared to W Scotland. But we often found marked differences between, say, Start Bay, Start Point to Bolt tail, Dart to Berry Head and Tor Bay. Someone sailing for a few hours in a relatively small area will often have wind quite different from that described in a brief text of a 24 hour forecast for a considerably larger area.
The forecasters quite often do not know about the detail that we experience. On a November passage from the Yealm to Dartmouth we had an early morning (0600 in those far off days) shipping forecast of SW 5 or 6 increasing 7 perhaps gale 8 later (ie after 1800). Around 1000 we were passing Bolt Tail with a F6. By Prawle Point it was F 7. By Start it was F 8. It then increased to F9 for about 15 minutes. It then decreased to F7 (allowing us to gybe towards the Dart) hen down to F5 entering the Dart.
Having not long retired, I complained to my former colleagues. They sent me copies of their working charts. They did not have a single report > F6 over the area. Analysing the chart, I could not get a wind > F6. It was a topographic effect on a scale that they could not know about. Even now, operational models cannot handle detail on this scale. Even if they could analyse on such a scale, I doubt they could predict on a routine basis.
JumbleDuck
Well-Known Member
Today's SE4-5 (Inshore waters) or S 10 - 14kt (GFS27 per Windguru) is currently flat calm with occasional 5 kt gusts from random directions.
KenMcCulloch
Well-Known Member
i've recently been converted to PocketGrib a smartphone app which uses GFS Grib files. The major advantage is that when there's only a poor GPRS data phone signal as in much of Scotland beyond the Central Belt, you are only downloading a realtively small data file rather than a web pge or pages. However if Simon K is launching a 10 day forecast I will definitely use that when I can.
franksingleton
Well-Known Member
At 1600 Islay 24 km/hr, Macrihabinh 22 k,/hr. See http://www.meteociel.fr/observations-meteo/temperatures.php?region=uk. Roughly, 2 km/hr = 1 knot. F4?
Fimacca
Well-Known Member
I cast an eye at the sky. Check the leaves on high trees whilst closing one eye. toss some bones on the sand and see how they fall in place. see if the chickens are in or out their hutch...............................................................................then I guess, just like the forecasters ! (sorry, downcasters. if I had cancelled my trips this year as i should have on the downbeat forecasts, I would have sailed about 6 days instead of 30 !! )
JumbleDuck
Well-Known Member
Neither of these, of course, being within the Inshore Waters area in question, though not far away. I'm marginally less imprressed by the GFS forecast than the Met Office one.
However, given that both the shipping forecast and inshore waters forecast areas are too large to be much use, and that the forecasts themselves are pretty rubbish - there is very rarely any consistency in the run up to a particular time - I wonder why bother at all with the radio forecasts. They may have been better than nothing fifty years ago, but they are by far the worst information available today.
franksingleton
Well-Known Member
Of course, you are splitting hairs in that Islay and Macrihanish are not in your area. They are near enough to make the point that the winds over the waters between Largs and Arran for the time of a short passage may well not represent the whole inshore area for 24 hours .
You are expecting unreasonable and unachievable accuracy in a forecast for an area of such complex topography. Even over open waters it is rarely, if ever, possible to describe the weather in a few words that would cover what anyone would experience at any time any where in the area. I am sure that you have sailed enough to know that.
I have said on many occasions that high seas, shipping and inshore waters forecasts can be little more than headlines. They are essentially a warning service. They MUST include mention of POSSIBLE weather hazards. They have to be written in very few words. The shipping forecast is limited to 330 words and that includes the preamble, the gale warning summary and the synopsis. As discussed in another thread the inshore waters texts have to fit into the NAVTEX time slot. Writing any such forecast comes down to the art of the possible.
Whether you use forecasts or not is a matter of personal choice. To me, taking notice of what the forecast says is just one of the many ways in which we minimise risk in a high risk activity. I said minimise because you will never eliminate all risk. You can, of course, do better by paying for a forecast tailored to your needs. Simon Keeling would, I am sure, be only too happy to get your business. The improvement may or may not be worth the expense but you can always try it and see.
My advice has long been to use GRIBs primarily for planning purposes. For that they have become an increasingly reliable tool. When cruising, around 4 months a year nowadays, I am continually looking a week ahead. Since GRIBs became available, around 2002, we have sailed many thousands of miles and had to make many decisions about when to move on or stay put. We may not always have made the best decision but we never got into trouble. I can fairly say that we were never in the wrong place at the wrong time whether at sea or in harbour.
For day to day use, I always say that GRIBs (and I include all other objective forecasts in that term) should not be used as a standalone service. They should be used to help in the interpretation of GMDSS texts.
When using any computer forecast, remember that values on a grid can only describe weather on a scale of around 4-5 grid lengths. GFS output is on a 25 km spacing. So, 60 mile is the best that the GFS can resolve. Largs to the middle of the east coast of Aran is about 12 miles.