Nadine - time for you to leave

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  • Satellite image of Hurricane Nadine on October 3rd. At the time, Nadine had winds of 50 mph. Image: NASA/LANCE MODIS.

    The convoluted path and changing strength of Nadine, from tropical wave near Cape Verde to tropical storm and hurricane (twice) before losing its identity on October 4th.

    Tropical Storm Oscar on October 4th - a far briefer storm, expected to last just a couple of days. Image: NASA/LANCE MODIS

  • Nadine - time for you to leave
    04.10.2012 16:20

     

    Sometimes guests just outstay their welcome.

    Nadine is an occupant of the Atlantic Ocean that has been loitering for a very long time. As a hurricane, tropical storm or tropical depression it has been meandering around the central and eastern Atlantic for 23 days as of October 4th, visiting the Azores on more than one occasion.

    It is now finally showing signs of atrophy as it moves farther north, and it should imminently lose its tropical characteristics then weaken further and merge with a mid-latitude low pressure system. It is encountering lower sea surface temperatures and so lacks the energy to sustain itself, while increasing upper level winds start to destroy its tropical structure.

    During the past three weeks Nadine has fed off the unusually warm waters of the Atlantic, and relatively calm conditions aloft have allowed it to maintain its integrity and last for such a long time.

    The ex-storm should run north-eastwards towards Scandinavia but in the mean time it may have an indirect impact on the weather in the UK. 

    Just as it did when heavy rain brought floods in late September, Nadine will help to pump warm, moist tropical air northwards. As this crosses paths with colder air coming southwards it will produce the right conditions for the development of low pressure systems that will deliver some heavy rain through the coming days.

    And that should be the last we hear of Nadine. However, there is a younger brother to the southwest called Oscar, a much shorter-lived tropical storm expected to last just a couple of days. This should also get absorbed by a run-of-the-mill depression and may come across Europe early to mid week.

    The extraordinary longevity of Nadine has made it the fourth longest-lasting Atlantic tropical cyclone known, in a database going back to 1851. It has lasted just a day longer than 2002’s Hurricane Kyle, which wandered westwards across the central and western Atlantic for an age before running northeast up the Eastern Seaboard of the USA. 

    The most persistent tropical cyclone in any ocean basin was Hurricane John – at least that we know of. In August and September 1994 its peregrinations took it across the northeast Pacific and northwest Pacific then back again for a total of 31 days.

    But who knows what storms might have patrolled the lonely oceans for even more than a month before satellites allowed us to spy them?

     

    By: Stephen Davenport