Canary Island Cloudbursts while Southern France Sizzles!

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  • The jet stream is taking very large north and south loops at the moment, with cool and unstable air bringing showery conditions to the Canary Islands, while warmth builds northwards over Spain and France.

    Striking temperature anomalies (compared to the late November average) over south-western Europe, as cool air arriving over the Canaries and north-west Africa displaces warmth northwards into Spain and France.

  • Canary Island Cloudbursts while Southern France Sizzles!
    20.11.2014 16:38

    There is great diversity in the weather conditions across south-western parts of Europe at the moment, with extremes of both high and low temperature and large differences in rainfall being experienced across relatively short distances.

    Some parts of the Canary Islands have experienced torrential downpours and flash flooding during the last 24 to 36 hours. Los Rodeos airport on Tenerife recorded 31.0mm of rain in 24 hours, much of which fell in less than 6 hours. Other more mountainous locations on the popular holiday island recorded between 50 and 75mm of rain. The steeply-sided volcanic landscape channelled excess rainfall runoff into huge torrents which swept rapidly down river valleys and led to flash flooding. Temperatures over the Canaries are currently between 5 and 8C below normal for late November. The next few days will see some sunshine, but also further heavy showers.

    If you are looking for a last minute European holiday destination this weekend, you could do a lot worse than take a flight to the south of France. Warm southerly wind flows from north Africa will bring unusually warm conditions here, with sunny spells and temperatures 5-10C above normal quite widely across the region. Max temperatures of 19-22C. The reason for these European weather extremes is down to a large southwards perturbation of low pressure over the north-eastern Atlantic, while a high pressure ridge builds north-eastwards across France and joins forces with the vast area of high pressure over Scandinavia. The jet stream (a narrow band of high level winds, around 5 – 7 miles above the surface) is sculpting these high and low pressure areas into these elongated shapes today.

    But why are weather systems taking this meandering pattern, rather than flowing in a direct route across the north Atlantic and bringing the UK a rapid-fire succession of wind storms? Very cold and snowy weather over the eastern USA and Canada, contrasting with the balmy sea temperatures off the eastern seaboard of the USA is super-charging the jet stream above Newfoundland today, before it heads out over the north Atlantic. This is sometimes a recipe for deep low pressure systems to form and then come barrelling right across the UK.

    However, a vast and stubborn high pressure area (or blocking high as forecasters call them), over Scandinavia is getting in the way. It has been there for several weeks now and is refusing to give ground for the time being. Each low pressure system crossing the Atlantic towards northern Europe is coming up against a meteorological brick wall, slowing down and then stalling over south-western Europe instead. For the time being at least, the UK will still receive spells of wind and rain at times, especially in the west, but not the full blown destructive storms that we saw last winter.

    By: Matthew Dobson