# Watch out for Willy



## Scott (Aug 29, 2005)

A trap for young players. Never trust Willy weather. Below is a screen shot for a storm bay forecast for next Sunday. According to Willy it will be 6.8 knots where as the more accurate BOM site predicts almost 30 knots by the time you take the 40% stronger gusts into consideration. Add the 1.5 to 2 metre seas and many fishing kayaks or inexperienced paddlers would be either taking a swim or unable to make headway against the wind.


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## Guest (Jan 25, 2013)

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## kayakone (Dec 7, 2010)

SteveR said:


> I've been misled by willyweather a few times. Had waves/wind turn worse than predicted while out learning to fish the ocean from a beach. Don't interpret the following as argument. That's not the intention.
> 
> This is an extract from http://www.willyweather.com.au/info/ter ... disclaimer
> 
> ...


I disagree Steve on BOM (generally speaking) having "poor forecast data". I believe their reliability in the general forecasts to be very high. It is WillyWeather (include Wind Guru and Seabreeze) who are most likely to inaccurately display data from NOAA and BOM.

BOM has the forecasters and computer modelling to make the forecasts very reliable. Whether this is passed on in a timely matter to the web sites of these private organisations is the question.

Also, it is important to remember, especially with kayaking, and other safety critical areas such as aviation, that a forecast is only a cast forwards. When you get close to launching (takeoff or landing), the critical data is _*observations*_, not forecasts (although the _latest_ forecast is still important for the duration of the planned excursion). It is BOM that has an extensive system of Automatic Weather Stations (AWS) around Australia, and this is very reliable and uptodate data of what is actually happening on the ground/sea/air.

There can be a dangerous mindset, where someone:

1. Is clinging to a forecast that is not the latest available.

2. Has not checked the latest observations for the area (real time data from the closest AWS).

3. Does *not* have a marine VHF. VHF, because that gives you access to severe weather warnings from VMR/Coastguard. This alone could save your butt, for despite being aware of and practised in all the above, there is the other variable known as rapid 'un-predicted' change, or rapidly advancing approach of a front/wind change. This is rare, but can happen due to the sometimes highly variable nature of weather systems. You at least have a chance if you have VHF. 
One example is say a Southerly change (viewtopic.php?f=18&t=59304). This saved the day, heatwise, but let's say BOM said it would arrive at Mascot at 3 pm, so you duck out for a two hour session on Botany Bay at 11 am. Safe as, except _after you leave_, it begins accelarating rapidly past Nowra, and will now hit you at 12.30 pm. VHF comms would be useful in this scenario, allowing you to be warned and get off the water safely.

Check out these threads:

viewtopic.php?f=9&t=52407&p=597763

viewtopic.php?f=9&t=56161&p=582688

viewtopic.php?f=3&t=51106

In summary, I'm with Scott. I've seen many forecasts so different from BOM as to be cautious about the data these sites provide. And as said, what really counts on the day, is what is actually happening (observations). BOM has the 'experts' and the real time data. It is BOM that keeps mariners and aircraft safe, not Willy and co.

trev


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## dru (Dec 13, 2008)

All the commercial sites are informative but ultimately problematic. So Willy Weather, Wind Guru, Sea Breeze - all the same. Rob Mercer talks about conversations with their site management. Effectively they have a commercial arrangement with the blokes who wrote the algorithms, but do NOT have any expertise on what it does. They down load data from BOM and load it in.

At least at the BOM if they got it wrong there is a bunch of blokes in panic mode issuing updates on actual current data. Constantly I see on these sites live data from Fort Dennison that agrees with the conditions I paddle in, but the prediction bears no relationship. And there are experienced people using that experience to common sense check the computers.

It's also concerning here that even well experienced yakkers express an attitude of ( my favourite weather site ) is perfect and acceptable evidence of the actual conditions. It isn't. We need to :
a) learn how to use the BOM properly, the info is superb
b) learn how to read the live conditions with our own eyes

These sites are useful, but on their own can actually be dangerous.


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## kayakone (Dec 7, 2010)

BigGee said:


> dru said:
> 
> 
> > All the commercial sites are informative but ultimately problematic. So Willy Weather, Wind Guru, Sea Breeze - all the same. Rob Mercer talks about conversations with their site management. Effectively they have a commercial arrangement with the blokes who wrote the algorithms, but do NOT have any expertise on what it does. They down load data from BOM and load it in.
> ...


THANKS GEE. I was expecting a host of dissenters, so I didn't comment.

trev


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## dru (Dec 13, 2008)

SteveR said:


> It is very strange that BoM are able to forecast a bad weather warning for Storm Bay but it is not reflected in the forecast data tapped by willyweather.


Yes and no. I am not familiar with this particular BOM reading, so comment on what is in my experience the most common cause of difference. Trev has made many posts on this too.

Generally we have overall weather conditions that the algorithms at the BOM, but also on the commercial weather sites, well they actually do pretty well with it. It's a pity that the commercial boys don't seem to adapt to the actual live data. This leads to senseless error, that makes it just too easy for a cynic like me to deride.

Outside of those overall weather patterns (where predictability is pretty good), the you have occasional weather "cells" (my term, haven't checked for technical correctness) which push through the generic conditions. These cells are well predicted by the BOM, but only really in generic terms. So we know that it's coming in the afternoon. But the commercial site algorithm then predicts how the cell will travel. Well it only has to miss by 30 or 40 k and the predictions are nonsense, in your particular area. So summer in Brisbane with afternoon storms on the back of building humidity, bounce off Toowoombah and attack the coast from the west.very predictable, but not the exact path or even the exact size. Check the BOM radar. The commercial sites are a fiction in these situations.

Similar, but not quite as obvious, is where we have significant weather changes. Here in Sydney we get those southerly changes (in summer) that are strong, gusty, shifty, and cooling. Kraley has called them "Gongers" which makes sense. A big change like that is more ubiquitous than the weather "cells", so more predictable. But still will only get within an hour of when it hits, and may hit the west earlier or later than the coast. The algorithms guess, or average or something. But they are not going to be right. Again the path could easily be 50k out.

As I mentioned earlier, the BOM then starts making live time corrections. The algorithm updates predictively, what every hour? It's only got that one chance to predict and doesn't have much of a live data input for corrections. Nor experienced individuals to make correction to changing live circumstances. They do OK all things considered.

But probably not the best thing to bet your life on.


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## Guest (Jan 25, 2013)

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## Squidley (May 8, 2010)

What I like about the BOM's forecast wind map is that it's a map, so you can be aware of a patch of 20+ knot wind a few kilometers away that could muscle in on your spot unexpectedly. Seabreeze and WW's charts appear to represent some single point in a region over time, and relying just on that forecast could get you into trouble or worse: make you miss out on a trip because you didn't see spot Y and Z were probably calm


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## Junglefisher (Jun 2, 2008)

My biggest problem with the BOM is that they predict the weather for our entire forecast area in one lump. We're talking an area 400km by 400km or so. The rain cells might only be 10km wide. Willy weather is a lot more useful to me for predicting rainfall than the "scattered showers and isolated thunderstorms" I get from the bureau.


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## dru (Dec 13, 2008)

Junglefisher said:


> My biggest problem with the BOM is that they predict the weather for our entire forecast area in one lump. We're talking an area 400km by 400km or so. The rain cells might only be 10km wide. Willy weather is a lot more useful to me for predicting rainfall than the "scattered showers and isolated thunderstorms" I get from the bureau.


Craig, it is usefull. I guess I don't use the rain features on BOM much so haven't watched closely how well it works. Also think its part of the terrestrial info rather than the marine side of things (?).

Another thing the BOM doesn't do too well, the morning lull. (opposite of the afternoon sea breeze). At sun up frequently conditions are mill pond when the overall weather conditions show wind. You have to interpret though, a southerly or westerly might be exactly to BOM data. SE E and NE can often be discounted at first light.


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## Guest (Jan 26, 2013)

I do have to agree with JF on that one. I look at the willy, seabreaze, windgruru and coastwatch (which just shows the bom forcast) and then make a judgement from there. With bom forcasting such a large area they are quite often over done on there wind predictions. This is magnified when you have places like Cape Morten and Dble Island Point which are a good 10 kts above any where else in the region which is why bom have higher predictions than other more localised forcasts.


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## kayakone (Dec 7, 2010)

nad97 said:


> I do have to agree with JF on that one. I look at the willy, seabreaze, windgruru and coastwatch (which just shows the bom forcast) and then make a judgement from there. With bom forcasting such a large area they are quite often over done on there wind predictions. This is magnified when you have places like Cape Morten and Dble Island Point which are a good 10 kts above any where else in the region which is why bom have higher predictions than other more localised forcasts.


Depends where you're going Nick. JF was, I think talking about a large land area and a general forecast. Within that area there _may_ be an AWS, which gives observations and trends. If I was paddling to Cape Moreton, I'd be interested in that reading, but also the Inner Beacon and the Spitfire Channel, as well as the trends from each, and the latest marine forecasts for the whole area.

Cape Moreton and DIP are two AWS's within the SE, but there are many others to reference. I say it again ... AWS measures observations - it is not a forecast (they measure real time data recorded every 30 minutes, and more regularly with marked changes within the half hour window). The variations between AWS's in close proximity, in some weather patterns, can be extreme, so it is worth clicking on a few to study these variations. Sometimes the variations are in both wind speed _and_ direction. You can detect a pattern and make educated guesses for the area you are likely to launch and paddle in.

trev


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## Rockster (Sep 7, 2007)

My 2 cents for what its worth. I'm with Nad97 & Tonystott. I have learnt to check out BOM, Willyweather & Sea Breeze, purely for the fact that they vary and try and make an informed decision. I have had instances where one or the other has got it wrong at different times. The best thing about BOM is the forecast is more likely to be up to date before heading out. Can be a pain in the backside to log on and check when you get up at 4.30 am and seeing conditions are going to deteriorate and have to call it quits. Its a bugger trying to get back to sleep.
Cheers
Bob


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## kayakone (Dec 7, 2010)

Rockster said:


> My 2 cents for what its worth. I'm with Nad97 & Tonystott. I have learnt to check out BOM, Willyweather & Sea Breeze, purely for the fact that they vary and try and make an informed decision. I have had instances where one or the other has got it wrong at different times. The best thing about BOM is the forecast is more likely to be up to date before heading out. Can be a pain in the backside to log on and check when you get up at 4.30 am and seeing conditions are going to deteriorate and have to call it quits. Its a bugger trying to get back to sleep.Cheers
> Bob


It's more of a bugger to get hurt, lose your yak or drown. BOM has the experts, the _only_ radars, wind and rainfall stations (AWS), and the wave recorders. The AWS stations will record every few minutes if certain parameters are changing rapidly (as opposed to the regular 30 minute schedule). Also, BOM meteorologists, working 24/7, are always available to alter a previous forecast and/or to issue a warning.

They are rarely out by more that a couple of knots (okay...that's a lot in a yak), or a degree or two in temperature. Similarly with rainfall predictions.






*Instead of 'British Paints', substitute 'Bureau Prognosis"*

Sure can.

trev


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## OldDood (Nov 6, 2008)

I would not trust any site, I have installed a weatherrock on the end of a piece of string in my backyard.
It has never failed me for accurate up to the minute data.
•If the rock is wet, it's raining.
•If the rock is swinging, the wind is blowing.
•If the rock casts a shadow, the sun is shining.
•If the rock does not cast a shadow and is not wet, the sky is cloudy.
•When the rock turns white, it is snowing.
•In the morning, if the rock is coated with ice, there is a frost. If the ice is thick, it's a heavy frost.

Of course, any of these conditions can be combined during confused weather conditions. With practice, you will become very adept at using your weather rock to determine weather conditions at your location.

 
Mark


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## exp2000 (Jul 9, 2011)

Yeah I think Willy weather is aptly named - I am sure he plays with it!

Seriously their predictions are crap over here. Seabreeze used to be good but likewise it has gone down the gurgler.

Maybe they phone up the psychic hotline or consult the entrails of an owl? Who knows?

I just check the forecats charts for predicted changes in the weather pattern and use recent conditions on the BOM site as a basis - by far the most reliable way to make a determination.

But generally our weather up here is much more stable in the short term than the souther latitudes.
~


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## Salty Dog (Sep 18, 2005)

Make sure you protect your rock from vandals with white paint Old Dood! ;-)


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