FORECAST DISCREPANCIES

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willtaylor

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-----Original Message-----

FROM GRUMPY OLD MAN

From: "WILL TAYLOR" <will.taylor1@btinternet.com>
Sent: 28/07/2007 00:15:19
To: "enquiries" <enquiries@metoffice.gov.uk>
Subject: Discrepancies between forecasts

I am puzzled. I want to go sailing over the weekend. My boat is kept in the river Tamar.

The specific (land) weather forecast for Plymouth suggests a range of wind speeds from 3 to 6 mph during Saturday, with a possible gust of 20mph overnight. For Sunday day winds are given as 8 mph and night as 2 mph.

The inshore waters forecast gives W or SW 3- 4 becoming 5 to 7 later and for Sunday SW veering NW 4-5 increasing 6 to gale 8 later.

The shipping forecast for Plymouth suggests W or SW 4 or 5 occasionally 6 .

Now I appreciate that Plymouth forecast is a land forecast. However, Plymouth is not a million miles from the inshore waters up to 12 miles offshore - maybe 12 miles, maximum.

However, there is an astonishing difference between 6 or 8mph (force 2+) - which is almost too light for sailing - and 21-33 knots (force 5 - 7) into which it might be imprudent to set out. The Sunday forecast contrasts a suggested 8mph (land) with 22 - 34+ knots ( force 6-8).

The inshore waters list has no pink underlining, nor does it mention that winds may reach the upper values mentioned. There is no red on the outline of Britain for the section Lyme Regis to Lands End.

It has been a very frustrating season. Weather has frequently not been so bad as forecast, though it has been wet enough in all conscience. However, with the local BBCTV forecasters being very positive about Saturday and Monday onwards I felt I could put up with heavy rain on Saturday night and Sunday morning by making for Fowey on Saturday and then moving on to Falmouth a bit later on Sunday if the rain was bad.

Now I am faced with an inshore waters forecast that tells me I shouldn't go and a land forecast for a coastal city that says there will be very little wind.

Can you explain these discrepancies? I do know that land winds are often lighter, but these differences are very significant.

Regards,

Will Taylor


REPLY

Dear Will,

Thank you for your recent email.

Due to the different update and validity times of the Inshore waters, gale warnings I can see how the forecast may come accross as slightly misleading.

However the current forecast now reflects the time that the strong winds are expected. The strongest winds are due this evening betweem 2100Z and 0900Z Sunday morning, this is associated with the heavy rain spreading East across the country.

http://www.metoffice.gov.uk/weather/marine/inshore_forecast.html?area=8&type=All

I hope this helps.

Kind regards

James

Customer Centre, Met Office, FitzRoy Road, Exeter, Devon, EX1 3PB, United Kingdom. Tel: 0870 900 0100 Fax: 0870 900 5050 Email: customercentre@metoffice.gov.uk
 
Feeling equally grumpy. Currently sitting on my boat in the marina at Southampton surveying ever lowering, ever darkening clouds.

In the small hours of this morning, and even first thing this morning - when I had to make my decision whether to com down from London today and do jobs on the boat - the Met Office forecast was for bright weather, changing this evening to cloud and then into rain as the night wore on.

It hasn't been bright since I got here, just heavily overcast and trying to rain. Now of course, when I log on, the Met Office site 'predicts' exactly what I am experiencing. And of course, tomorrow is going to be better, except I've made my plans based on what they were saying this morning and now I can't be here tomorrow.

If they can't forecast - not even 12 hours ahead for pete's sake - and will just post up observations that I can make for myself, what on earth is the point of all those expensive computers and all that allegedly amazing forecasting software? Even more bizarre is the mismatch between the BBC weather forecasts - supposedly supplied by the Met - and the Met Office website itself.

Utterly, utterly useless. I'd have more sympathy if we were dealing with fast moving systems, but it's very clear from simple observation here in Southampton that we are not.

/forums/images/graemlins/mad.gif
 
Slight discrepancy up here. Little pessimistic if anything

http://www.bbc.co.uk/weather/5day.shtml?id=2453&links

Web Cam 4 mins ago

WebCam.jpg
 
If you have access to the internet use METEOX.com which shows the rain and cloud movement. It is easy to predict yourself up to 6 hours ahead. If you use it often you will find that rain travels in bands and the BBC and Met Office just don't know the exact latitude of these bands. What really surprises me is that the radio and TV stations also don't appear to use rain radar when giving their missleading reports.
 
Totally agree, forecasts have been astonishingly bad lately and changing from day to day. What i can't understand is why the BBC forecast that supposedly comes from the Met-Office is so different from the Met-Office forecast.
 
I find the BBC Wales TV forecasts excellent for everything except wind, which is almost always low by sometimes a factor of two. They are showing land winds for land based communities. The BBC website (and most www weather sites) end up doing the same. I take note of the BBC TV weather to get a picture of sun / rain and the timing of systems passing over...but for sailing winds the only forecasts that I have any faith in are those such a Windguru Pro MM5 and associated maps. Yes you have to pay, but it's peanuts really for what you get.
 
[ QUOTE ]
If you have access to the internet use METEOX.com which shows the rain and cloud movement. It is easy to predict yourself up to 6 hours ahead. If you use it often you will find that rain travels in bands and the BBC and Met Office just don't know the exact latitude of these bands. What really surprises me is that the radio and TV stations also don't appear to use rain radar when giving their missleading reports.

[/ QUOTE ]
....and I think they usually fail to use that very useful technique of 'looking out of the window'!
 
...On the plus side it appears that the recent flooding has been caused by a low pressure system which has been static.

Things are looking up as the system has finally moved through and there is some high pressure on the way. If this too is slow moving then perhaps we could be in for some good weather and maybe even a heat wave.

Maybe that's a little optimistic but we'll have to wait and see. Apparently the heat on the other side of Europe was caused by the exact scenario - while we were stuck with low they had a static high.

In the meantime weather in the South will pick up. So it might be worth booking a few days out of the office while the going is good.
 
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