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jay007

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Posts posted by jay007

  1. Not a daft question at all. Around a trough the upper air is flowing anti-clockwise or cyclonic, and with a ridge the upper air is flowing clockwise or anticyclonic. On the chart above the trough is pretty much over the UK, perhaps more over north-west UK. So if you look at the different coloured shadings which represent heights, just follow them and that is the direction of the upper flow.

    Or, instead of looking at the 500mb charts, you can take a look at this chart which shows the airflow at different pressure levels in the atmosphere (available via Netweather's Extra Subscription):

    post-9715-068684100 1285540919_thumb.png

    The one of most relevance in terms of storm motion will be the 500mb panel in the bottom left corner. Hope this helps.

    It took me a while to digest what you was telling me but i think i have cracked it lol

    Following the first chart you gave me i followed the yellow colour anticlockwise and it all make's sense thank you.

    Thank you weather09 for your guidance, you have clear up a question that i have had for a while , your advice was brilliant i can't thank you enough.

    jay

  2. Thunderstorms don't always travel from south-west to north-east, but is a fairly common direction for storm motion given that the flow over the UK is predominantly from a W/SW direction, due to low pressure systems that come in off the Atlantic. Thunderstorms are guided by the upper (steering) winds at around the 500mb level, and so it depends on where a trough (upper low) is positioned in relation to the UK.

    Here is a 500mb and surface pressure chart from the GFS for Thursday just gone:

    post-9715-025668300 1285535572_thumb.png

    The colours represent heights and show the direction of the upper (500mb level) flow. So from this chart you can see that the upper flow on that day was flowing from SW-NE across England and Wales, and this is the direction the storms moved in during that afternoon. If the upper low was positioned, say, a little east of the UK then, provided the air mass was unstable, storms that develop in that scenario would travel from the east or north-east towards the west or south-west.

    Hope this helps.

    And welcome to the forum. :)

    Hi weather 09

    thank you for replying to my post

    Thank you for the info its helped a little, i understand the colours and heights on the chart but i'm struggling to understand the direction of the upper flow, what part of the chart is repesented by the direction of flow?

    Im sorry if this is a daft question, im still trying to get my head around weather charts lol

    Thank you for your welcome :)

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