UK meteorology

chrisbell said:
If my explanation is still confusing, the following link is a pretty good reference, though it refers to 500mB/hPa charts and airflow diverging at the top of a low pressure cell, neither of which I wasn't going to mention yet:
http://www.atmo.arizona.edu/students/courselinks/fall12/atmo336/lectures/sec1/p500mb.html

From that link, the following image is a simplified northern hemisphere chart derived from a model output, with the North Pole in the centre, as though you were directly hoving above it and viewing the northern hemisphere from that angle:


longwave_hemisphere_new.png


As the caption states, this is a Wave 5 pattern, with the ridges numbered.

Below is another diagram from the same linked site, showing the difference between a zonal and meridional jet:

terminology_500mb_new.png
Click to expand...
So warm wet and windy for a while , could be worse! :)
 
Brief model update - mild or very mild for all, with rain and gales in the north-west (western Scotland in particular) over the next few days, and some rain tomorrow and Saturday further south and east. From around next Tuesday, turning cooler and sunnier, in particular in the south and east as the high pressure shifts position, though more unsettled further north and west. Temperatures well above average initially (12-16C), dropping closer to average from the middle of next week (8-14C). From next weekend (17th and 18th December), there is some uncertainty regarding where the high pressure will set-up; the most likely orientation is an elongated cell from France and the south-east of the UK running WNW to the Czech Republic. This would bring milder, cloudier and more unsettled conditions to the north and west, with drier, brighter and frostier weather further south and east. Towards Christmas, there are some indications that the high may "retrogress" (move east-to-west against the prevailing flow) to set-up to the north-west of the UK by around the Winter Solstice. This would pull in a north-easterly flow, which would bring colder conditions with wintry showers to the north and north-east of the UK, especially over high ground. However, at this stage, there is a great deal of uncertainty; mild south-westerlies for the period in question are also possible if the strength of the jet runs to the north of the high, causing it to 'sink' south and east back to its current position (as of 7th December).
 
Model update - any sign of the high pressure moving to sit to our north-west has diminished. Rest of the month likely to be unsettled, with, as usual, the brunt of the wind and rain being for the north and west, though the south and east will also see wet and breezy weather at times. Really, the only uncertainty at present for later in the month and the Christmas period is the exact location of the nuisance European high - if it drops south and west back to the Azores from whence it came, the flow will be fom the west. This would put most of the country into unsettled weather with temperatures around average. If it stays over south-west Europe, as it is at present, the south and east will be mainly dry, cloudy and exceptionally mild (14-16C), while areas further north west will be wetter, windier, and around average temperatures (low double figures Celcius). Anyone who was considering a flutter on a White Christmas would be well advised to hang onto their money.
 
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chrisbell said:
Model update - any sign of the high pressure moving to sit to our north-west has diminished. Rest of the month likely to be unsettled, with, as usual, the brunt of the wind and rain being for the north and west, though the south and east will also see wet and breezy weather at times. Really, the only uncertainty at present for later in the month and the Christmas period is the exact location of the nuisance European high - if it drops south and west back to the Azores from whnce it came, the flow will be fom the west. This would put most of the country into unsettled weather with temperatures around average. If it stays over south-west Europe, as it is at present, the south and east will be mainly dry, cloudy and exceptionally mild (14-16C), while areas further north west will be wetter, windier, and around average temperatures (low double figures Celcius). Anyone who was considering a flutter on a White Christmas would be well advised to hang onto their money.
Click to expand...
Don't know if you saw 'dangerous earth' BBC 4 last night - chasing tornadoes? If not, there's always iplayer..:)
 
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