simonjk
Well-Known Member
Good afternoon,
Hope the week has gone well for you and that you are looking forward to the weekend, hasn't this year flown by? From all the gumph I've been receiving in the post over the last few days you'd think Christmas was next week, not almost two months away!
And of course, as a weatherman, I'm geting asked everyday about whether it will be a white Christmas. I'd never give a forecast that far in advance for any particular date, but at the moment I'm advising my clients that the winter will be colder than the past few years and we should see a few daysof snow on the ground. I don't expect a 1963 but it might seem cold when compared to the mild winters of the 90's.
Anyway, I digress, it's a problem enough getting the next 3 days right let alone the next two months!
We should see a change in weather pattern this weekend as the nasty little low we've had to the south of Ireland for the past few days slips away into the bay of Biscay. A build of pressure then from the west, with a ridge toplling through ireland and Scotland on saturday, then through the UK
on Sunday.
It's interesting to look at the 500mb charts for the next few days. If you remember, the 500mb chart represents a height at about 18000ft. Why use this you may ask? Well, the weather takes place above out heads, not at the surface and so if we can see what is going on aloft we can get a good feel as to what weather conditions are like at the surface. It's a bit like looking at the weather in 3D as opposed to the 2D surface charts we are used too.
So, bring up http://expert.weatheronline.co.uk/z500_frame.htm in a new window on your browser. The first frame of the chart shows an upper low over southern ireland and southwest England, with a ridge building to the west of Ireland. This is nicely setting up the pattern for the weekend.
Look at the chart for 00 UTC on Sunday (This is 0001hrs Sunday). The upper low has slipped south to be over the Pyranees with the ridge building through Ireland. The ridge equates to higher pressure building at the surface through the UK whislt the upper low is akin to lower pressures at the surface over France, Spain and the western Mediterranean.
At this time of year if you get the upper low in the western Mediterranean it can be a real so and so to clear. This is born out by looking at http://expert.weatheronline.co.uk/z500_frame.htm
These charts take us through to Wednesday 10th November and even then there is a trough in the western Mediterranean. By Tuesday 9th the UK is starting to see a breakdown in conditions. although the ridge is maintained over the south.
It may be that this is a little to quick for a breakdown and I suspect that southern England may hold onto higher pressurefor a while to come.
So what does all this mean for the UK and Ireland? Well I think that once this weekend is out of the way we are in for a quiter spell. Mist and fog is likely to become a problem and this could be reluctant to clear some places during daylight periods. Scotland should fair a little better with the winds a little stronger here, clearing the mist and fog more quickly. If you're a gardener, watch the forecast carefuly for risk of frost.
As for the sea temperature anomalies, look at http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.10.26.2004.gif
Remember that we have been looking at the cooler than usual water in the North Atlantic for a few months? This has now drifted to the west of the UK with temperatures around 1 to 2C below what we would expect. Could this aid the high development by inhibiting convection? It is interesting to
Interesting too to compare this to last year, look at http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.10.25.2003.gif
Most of the Atlantic was above normal (although not by much)
Hope that's been interesting for you. It's a fascinating weather World isn't it?
Best wishes,
Simon
Simon Keeling
web: http://www.weatherweb.net
wap: http://wap.weatherweb.net/
<hr width=100% size=1>Simon Keeling
Weather Consultancy Services Ltd
weatherweb.net & atlanticweather.co.uk
Hope the week has gone well for you and that you are looking forward to the weekend, hasn't this year flown by? From all the gumph I've been receiving in the post over the last few days you'd think Christmas was next week, not almost two months away!
And of course, as a weatherman, I'm geting asked everyday about whether it will be a white Christmas. I'd never give a forecast that far in advance for any particular date, but at the moment I'm advising my clients that the winter will be colder than the past few years and we should see a few daysof snow on the ground. I don't expect a 1963 but it might seem cold when compared to the mild winters of the 90's.
Anyway, I digress, it's a problem enough getting the next 3 days right let alone the next two months!
We should see a change in weather pattern this weekend as the nasty little low we've had to the south of Ireland for the past few days slips away into the bay of Biscay. A build of pressure then from the west, with a ridge toplling through ireland and Scotland on saturday, then through the UK
on Sunday.
It's interesting to look at the 500mb charts for the next few days. If you remember, the 500mb chart represents a height at about 18000ft. Why use this you may ask? Well, the weather takes place above out heads, not at the surface and so if we can see what is going on aloft we can get a good feel as to what weather conditions are like at the surface. It's a bit like looking at the weather in 3D as opposed to the 2D surface charts we are used too.
So, bring up http://expert.weatheronline.co.uk/z500_frame.htm in a new window on your browser. The first frame of the chart shows an upper low over southern ireland and southwest England, with a ridge building to the west of Ireland. This is nicely setting up the pattern for the weekend.
Look at the chart for 00 UTC on Sunday (This is 0001hrs Sunday). The upper low has slipped south to be over the Pyranees with the ridge building through Ireland. The ridge equates to higher pressure building at the surface through the UK whislt the upper low is akin to lower pressures at the surface over France, Spain and the western Mediterranean.
At this time of year if you get the upper low in the western Mediterranean it can be a real so and so to clear. This is born out by looking at http://expert.weatheronline.co.uk/z500_frame.htm
These charts take us through to Wednesday 10th November and even then there is a trough in the western Mediterranean. By Tuesday 9th the UK is starting to see a breakdown in conditions. although the ridge is maintained over the south.
It may be that this is a little to quick for a breakdown and I suspect that southern England may hold onto higher pressurefor a while to come.
So what does all this mean for the UK and Ireland? Well I think that once this weekend is out of the way we are in for a quiter spell. Mist and fog is likely to become a problem and this could be reluctant to clear some places during daylight periods. Scotland should fair a little better with the winds a little stronger here, clearing the mist and fog more quickly. If you're a gardener, watch the forecast carefuly for risk of frost.
As for the sea temperature anomalies, look at http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.10.26.2004.gif
Remember that we have been looking at the cooler than usual water in the North Atlantic for a few months? This has now drifted to the west of the UK with temperatures around 1 to 2C below what we would expect. Could this aid the high development by inhibiting convection? It is interesting to
Interesting too to compare this to last year, look at http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.10.25.2003.gif
Most of the Atlantic was above normal (although not by much)
Hope that's been interesting for you. It's a fascinating weather World isn't it?
Best wishes,
Simon
Simon Keeling
web: http://www.weatherweb.net
wap: http://wap.weatherweb.net/
<hr width=100% size=1>Simon Keeling
Weather Consultancy Services Ltd
weatherweb.net & atlanticweather.co.uk
