Sunday Updated to Severe Weather

simonjk

simonjk

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Joined
6 Mar 2003
Messages
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www.sailingweather.co.uk
Morning everone,

Just to update you; looks like exceptionally sdtrong winds affecting much of the UK today. Emphasis is across Scotland, Irish Sea, Shannon and Londy. I think we could find gusts over the Irish Sea especially in excess of 80kts. Gusts already to 60kts inland Wales.

Simon

ukpr12.gif
 
This is one of those situations where a knowledge of DIY forecasting is invaluable. The models do tend to smooth wind speeds too much and this can sometimes become dangerous, especially in situations such as those we have at the moment.

The lesson? NEVER 100% trust a model forecast; we forecasters look at many models, use our experience and then make a prediction based on a combination of these.

Data is useful, but knowledge is invaluable! (Soprry, does that sound patronising, it isn't soupposed too?)

Best regards,
Simon
 
[ QUOTE ]

Data is useful, but knowledge is invaluable! (Soprry, does that sound patronising, it isn't soupposed too?)



[/ QUOTE ]
Fear not..Not taken as patronising.

I saw this coming and did not go out sat cos i figured that getting back into chi today would be no fun at all.

I assume that forcasts are done starting with what is happening now.. plus what lows/highs etc are where... and then extrapolating what will/might happen next.. based on an ever expanding amount of data ref what happened last time sim conditions etc prevailed...
i find it a tad worrying that any current forcast is based on a starting point of "now" and your forcast for today/tommorow/ next week is based on about a F4 "now".. when it is in fact F6 gusting 7.
I realise weather and forcasting is a staggeringly complex problem.. but the starting point can be and often is 24 hours behind reality.
vast amounts of number crunching goes on world wide and future models worked on constantly.
would not forcasts be better served if more of the available resources were devoted to updating "now" closer to reality?
Not intending to knock you in any way. This seems to apply to all forcasts... Metcheck has consitantly proved to be as good and very often better than others
 
Not sure what forecast you were looking at but Met Office Inshore Selsey to Lyme Regiis is F5 - 6 occasionally 7 decreasing to 4 later, which I interpret as the overinght period to 06-00 Monday. Seems pretty spot on looking at reported wind speeds
 
Coming back into Chichester was fine today - just came in before hw, 1/2 genoa - 6 knots ... having left Lymington 3 hours before.
 
Agree sailing was exciting but quite OK, but as above Met Coastal prediction was spot on today in Solent F6 and partic thanks to Simon for early tip on here Friday as it allowed us to plan for Sun rather than Sat and taking things carefully today, still get a good sail.
 
[ QUOTE ]
Coming back into Chichester was fine today - just came in before hw, 1/2 genoa - 6 knots ... having left Lymington 3 hours before.

[/ QUOTE ]

Leaving Chichester heading for Gosport was quite another matter! Felt like I'd been beaten up by the time we arrived back!!

Mark
 
Simon, what system is used for showing wind speeds on your charts? I'm used to arrows where each Beaufort force is shown by half a flight, but I have seen charts where each flight shows 10 knots, and (once) where a flight shows 10m/s.

I ask because in your chart the worst that I can see for the Irish Sea area is apparently F2 (one flight), and even out in the Atlantic no more than F6.
 
Hey Victoruous, knock away, it's all part of forecasting!

You are right, and it is a very important point that forecasts are only as accurate as the initial dataset that goes into them. Lots of computting power is spent trying to sort out 'dodgy' data, although some will still get through.

To try to improve the nowcast the initial data set is supplemented using the previous run of the model for the same data time.
 
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