Twister_Ken
Well-known member
The weather data from Chichester bar is available online at <A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again
I love Chimet, but it worrries me
- Thread starter Twister_Ken
- Start date
ChrisE
Active member
It was certainly quite spectacular
I'm not surprised, when the cold front came through it rattled the windows in Lymington a bit. Not sure that you wouldn't have been expecting it. If you had been fool enough to be out yesterday, the increase in wind was accompanied by a large black 'omygod' cloud. The whole was followed by the best rainbow I've seen in a while.
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I'm not surprised, when the cold front came through it rattled the windows in Lymington a bit. Not sure that you wouldn't have been expecting it. If you had been fool enough to be out yesterday, the increase in wind was accompanied by a large black 'omygod' cloud. The whole was followed by the best rainbow I've seen in a while.
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robp
Active member
Have to say it is useful! I was monitoring it yesterday morning between 0630 and 0800 to aid my decision. Although I was being encouraged by good strong crew, I was concerned about just that front. It was only to move the boat from Langstone to Chichester and could just have been a great sail. Later, whilst sitting in the sun in the Yacht club for mum's day lunch, I regretted not going for a while but not now!
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jimi
Well-known member
Re: It was certainly quite spectacular
Last winter went from Yarmouth to Poole in F7/8 but there were some horrendous gusts where the readings were off the scale. In the squalls the sea was flattened and the surface of the sea blew off reducing vis to zero. We coped by letting the main go completely and switching the engine on to keep motion through the water rather than just be luffed up completely. Did wonder if the sails were going to blow out though!!
<hr width=100% size=1>I Have The Body Of A God... Buddha
Last winter went from Yarmouth to Poole in F7/8 but there were some horrendous gusts where the readings were off the scale. In the squalls the sea was flattened and the surface of the sea blew off reducing vis to zero. We coped by letting the main go completely and switching the engine on to keep motion through the water rather than just be luffed up completely. Did wonder if the sails were going to blow out though!!
<hr width=100% size=1>I Have The Body Of A God... Buddha
ParaHandy
Active member
... now if you had my (patented) flatulent compass bubble then you'd know during passage of such a gust to take immediate corrective action ..
ooohh, might like to know that device is named the Brot-yn-safe after well-known manufacturer of tinned nourishment .....
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ooohh, might like to know that device is named the Brot-yn-safe after well-known manufacturer of tinned nourishment .....
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tome
New member
The mean wind speed is sampled every second and averaged over 5 minutes.
The wind gusts take the highest of a 3 second moving average, again over a 5 minute average.
There's a complete description of the sensors and data reporting on the <A target="_blank" HREF=http://www.chimet.co.uk/tech.htm> technical pages </A> of chimet.
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The wind gusts take the highest of a 3 second moving average, again over a 5 minute average.
There's a complete description of the sensors and data reporting on the <A target="_blank" HREF=http://www.chimet.co.uk/tech.htm> technical pages </A> of chimet.
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brianhumber
New member
The wife and I were working outside on Ronhilda yesterday and I had just mentioned we would not be sailing to France at Easter if the weather was like this, when several almighty gusts went through at around 4.15.
She just looked at me, and started to talk about a lengthy spell on the Black sea this summer to complete the dacha refurbishment. Later I was given details of the marina in Odesa off the internet - Perhaps this was a hint.
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She just looked at me, and started to talk about a lengthy spell on the Black sea this summer to complete the dacha refurbishment. Later I was given details of the marina in Odesa off the internet - Perhaps this was a hint.
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pandroid
Active member
On my Weather course, Alan Watts taught me that you can expect a gust of up to 3 times mean (forecast) speed at any one time. He gave me a graph that I have somewhere which I can dig out if people are interested.
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davel
Active member
I'm a Chimet fan as well.
I particularly like their WAP service (url available from the web page) whih means I can access their measurements from my mobile whilst sailing, without the need for any PC connections.
<hr width=100% size=1>Dave L.
I particularly like their WAP service (url available from the web page) whih means I can access their measurements from my mobile whilst sailing, without the need for any PC connections.
<hr width=100% size=1>Dave L.
StephenSails
Active member
Hi Ken,
Your 16.10 gust came through Bosham minutes later in the form of a torrentail downpour of heavy rain and hail, the wind was light to breezy beofre but must of been blowing 6-7 when it came through here. You could see it comming for miles around as there was a large anvil cloud. I think I would have reefed up a some sail if I had been out on the water and seen that one comming.
<hr width=100% size=1>Visit my discount online chandlery and news site
<A target="_blank" HREF=http://www.yachtinguniverse.com>http://www.yachtinguniverse.com</A>
Your 16.10 gust came through Bosham minutes later in the form of a torrentail downpour of heavy rain and hail, the wind was light to breezy beofre but must of been blowing 6-7 when it came through here. You could see it comming for miles around as there was a large anvil cloud. I think I would have reefed up a some sail if I had been out on the water and seen that one comming.
<hr width=100% size=1>Visit my discount online chandlery and news site
<A target="_blank" HREF=http://www.yachtinguniverse.com>http://www.yachtinguniverse.com</A>
Twister_Ken
Well-known member
Thanks,
In a strange way that's rather reassuring.
There was also a shift associated with the big gust*, but strangely, the shift came 5 minutes before.
Time Wind dir
1540 251
1545 248
1550 247
1555 246
1600 245
1605 270
1610 280*
1615 282
1620 296
1625 293
1630 283
1635 276
1640 271
Can't help wondering if that - or a similar - shift and gust is what caused havoc on the Thames during Sundays' vets head of the river race.
<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>
In a strange way that's rather reassuring.
There was also a shift associated with the big gust*, but strangely, the shift came 5 minutes before.
Time Wind dir
1540 251
1545 248
1550 247
1555 246
1600 245
1605 270
1610 280*
1615 282
1620 296
1625 293
1630 283
1635 276
1640 271
Can't help wondering if that - or a similar - shift and gust is what caused havoc on the Thames during Sundays' vets head of the river race.
<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>
Kristal
New member
On passage between Harwich and Woodbridge yesterday, under power, I was halfway up the Deben when a squall hit us. I reckon it must have been about 1400 - 1430. There were dark clouds gathering all around, and then suddenly had F7 or 8 gust accompanied by hailstones, and then enormous spots of rain, followed by a heavy shower.
There was another gust about an hour later once entering the Tidemill, just when I didn't need it, which blew the bow over, and put us on the mud!!
I've only put this boat aground twice, and both times have been in this marina!
/<
<hr width=100% size=1><A target="_blank" HREF=http://www.crystaltwo.co.uk/>Crystal II in Pictures</A>
There was another gust about an hour later once entering the Tidemill, just when I didn't need it, which blew the bow over, and put us on the mud!!
I've only put this boat aground twice, and both times have been in this marina!
/<
<hr width=100% size=1><A target="_blank" HREF=http://www.crystaltwo.co.uk/>Crystal II in Pictures</A>
Evadne
Active member
Re: gusts and wind shifts
I know that sharp wind shifts occur as particularly active fronts pass overhead, and I always thought that the biggest squalls are caused by downdraughts from big cumulus or cumulonimbus clouds. As a cold front is a wedge shape in cross section, any clouds riding on it at a couple of thousand feet will be a bit behind the front on the ground. If you look at the pressure at the same time as the wind shift, there should be a fall followed by a sharp rise with the cusp at the moment the front passes, if this is what was happening, and the strongest winds would follow shortly afterwards.
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I know that sharp wind shifts occur as particularly active fronts pass overhead, and I always thought that the biggest squalls are caused by downdraughts from big cumulus or cumulonimbus clouds. As a cold front is a wedge shape in cross section, any clouds riding on it at a couple of thousand feet will be a bit behind the front on the ground. If you look at the pressure at the same time as the wind shift, there should be a fall followed by a sharp rise with the cusp at the moment the front passes, if this is what was happening, and the strongest winds would follow shortly afterwards.
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Twister_Ken
Well-known member
Air temp & pressure
There would have been a noticeable (3.0 deg C) drop in air temp just before big gust*, but you'd need to have been eagle eyed to spot a 0.8mb jump on the barometer.
Time Temp Pressure
1540 10.1 1005.5
1545 9.9 1005.5
1550 9.8 1005.6
1555 9.5 1005.6
1600 9.6 1005.7
1605 6.6 1006.5
1610* 7.0 1006.4
1615 8.1 1006.5
1620 8.4 1006.4
1625 8.6 1006.4
1630 8.7 1006.3
1635 8.6 1006.4
1640 8.3 1006.4
<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>
There would have been a noticeable (3.0 deg C) drop in air temp just before big gust*, but you'd need to have been eagle eyed to spot a 0.8mb jump on the barometer.
Time Temp Pressure
1540 10.1 1005.5
1545 9.9 1005.5
1550 9.8 1005.6
1555 9.5 1005.6
1600 9.6 1005.7
1605 6.6 1006.5
1610* 7.0 1006.4
1615 8.1 1006.5
1620 8.4 1006.4
1625 8.6 1006.4
1630 8.7 1006.3
1635 8.6 1006.4
1640 8.3 1006.4
<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>
Evadne
Active member
Re: Air temp & pressure
The cold air would be associated with a downdraft from a big cumulonimbus rather than the change in air mass due to a front, otherwise it would have stayed cold. 0.8mb in 5 minutes is quite a noticable rate, if it had carried on, but the sort of effect you get with the passage of a strong front is usually more sustained.
All in all it sounds I was right to stay in and watch it through a window, rather than trying to apply antifoul.
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The cold air would be associated with a downdraft from a big cumulonimbus rather than the change in air mass due to a front, otherwise it would have stayed cold. 0.8mb in 5 minutes is quite a noticable rate, if it had carried on, but the sort of effect you get with the passage of a strong front is usually more sustained.
All in all it sounds I was right to stay in and watch it through a window, rather than trying to apply antifoul.
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BlueSkyNick
Active member
For the W Solent ...
....... you can get similar info from <A target="_blank" HREF=http://www.channelcoast.org/data_management/met_charts/?table=envdata_Lymington_met> this site </A> which is on the Royal Lymington starting platform.
<hr width=100% size=1>I'm average size, Its just that everybody else is short.
....... you can get similar info from <A target="_blank" HREF=http://www.channelcoast.org/data_management/met_charts/?table=envdata_Lymington_met> this site </A> which is on the Royal Lymington starting platform.
<hr width=100% size=1>I'm average size, Its just that everybody else is short.
