Severe Heatwaves in Europe and North America

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  • Forecast maximum temperatures for the 2nd and 3rd August in Oregon and Washington. Credit: NWS Portland.

    Observed maximum temperatures for August 4th. Credit: MeteoGroup.

    Observed minimum temperatures for the night of August 3rd. Credit: MeteoGroup.

  • Severe Heatwaves in Europe and North America
    05.08.2017 18:19

    Summer may have halted in the UK for the time being, but it is currently biting hard across southern Europe, with the region suffering its worst heatwave since 2003. Record-breaking heat has also been recorded in the US Pacific Northwest recently. 

    Severe heatwave in Southern Europe

    Throughout this week, much of Southern Europe has been affected by some serious heat. Spain, Southern France, Italy, the Balkans and parts of Central Europe have seen record-breaking temperatures, as the most extreme heatwave in over a decade set-in. With a ridge of high pressure sitting over the region for a week, sunny skies by day and light winds have helped temperatures to build day-on-day.  August 4th, saw a high of 42.8C (109F) recorded in Rome, while the highest temperature of the heatwave so far, of  44C, (111F), was recorded in Sardinia. Although these parts of Europe are used to high temperatures in the summer, maximum temperatures are still 10-15C above the average for this time of year. Many national weather services placed parts of their countries on the most extreme high temperature warnings, while in Albania, the country’s armed forces had to be called in to help firefighters battled dozens of forest fires.

    The extreme heat worsens the situation in Italy, which is suffering from the most severe drought in living memory. In Rome, many of the city’s fountains have been turned off, with drastic water rationing only narrowly avoided last week. And there has been little respite during the nights: Loreto on the northern Adriatic coast recorded a minimum of 31.0C (88F) on the night of the 3rd August. The severe daytime heat has also corresponded with exceptionally high humidity – with several locations in Italy recording maximum dewpoints of over 30C, exacerbating the heat stress felt by humans and animals.

    The heatwave is expected to peak through Saturday and Sunday, with temperatures in the mid-40s Celsius possible across southern Italy and the Balkans. A brief cool down will occur here later on Sunday, as a weak cold front moves in from the west, although the heat is expected to build once more towards the middle of next week.

    The heatwave has helped to fuel a strong meridional temperature gradient across Europe, which in turn has strengthened the jet stream recently. The jet has been taking a southerly track across the southern half of the UK and northern Europe, resulting in cool and showery conditions with below-average temperatures here.

    Heat in the US Pacific Northwest

    This part of the USA is typically not used to extreme heat, - in fact, Seattle has a similar oceanic climate to London. However, earlier in the week, Seattle was forecast to break the 100F (38C) barrier on the 3rd August, for only the third time in 123 years, while Portland, Oregon was expected to get to 107F (42C). In the end, Seattle reached 94F (34C), which is a serious health issue for a city where less than a third of residents have air conditioning. The 105F (41C) recorded in Portland broke the 65-year-old day record. The heat also resulted in numerous wildfires breaking out in the region, leaving to air pollution advisories being issued, as the smoke plumes could be seen from space! 

    By: Richard Martin-Barton