Deep above the Bay of Biscay

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Deep above the Bay of Biscay: Deep Klaus , hurricane on January 24, 2009

A low pressure area over the Bay of Biscay , between the British Isles and Spain, off the west coast of France, is called a low over the Bay of Biscay ( Biscayatief , also low in southwestern Europe ) . It is a rarer form of the Atlantic lows .

Origin and Movement

Train routes to van Bebber

A Biskaya low occurs when the westerly wind drift with weak Azores high and pronounced North Atlantic oscillation or North Atlantic highs directs the incoming lows exceptionally far south towards Europe, or when it forms as a drag vortex of a mighty North Sea or Scandinavian high in the Biscay region itself. Overall, they are typical in the winter half-year, when the westerly wind zone shifts southwards towards the subtropics .

These lows run to the Western Alps to, and therefore propose two typical storm tracks one: either through northern France and southern Germany to the northeast, from where they then Central Europe Deep calls, or the South of France in the Mediterranean ( flyway  Va according Bebber ), where it then as Genoa deep out become.

Effects

A low over the Bay of Biscay creates a south-westerly high-altitude current over the Pyrenees and thus to a foehn , or a south-east warm current from the Mediterranean into the Languedoc and Roussillon , winds called Autan . As a result, the effect shifts across the Alps, creating foehn or foehn situations there . In extreme cases, southern currents can lead to Saharan dust phenomena.

At deep lows over the Bay of Biscay or near the British Isles , polar cold air can also push deep south over the eastern Atlantic and lead to cold spells in northern Spain and southwestern France .

Storm lows that move across the Bay of Biscay can be extremely violent, such as Hurricane Lothar in December 1999 (Central Europe type) or Hurricane Klaus in January 2009 (Mediterranean type, Va).

Individual evidence

  1. ↑ the Central Europe type does not appear explicitly in the graphic, it runs a little south of the IVb type ( Jutland type )
  2. ↑ Example: Deep Günter October 2003: a powerful low over the central Atlantic 17 / 18 , in a row 19 / 20 over the Bay of Biscay, decomposes 21 over the Northern Alps (Günter I, II) , the latter takes 22 to Eastern Europe from (all links analysis maps, met.fu-berlin.de)
  3. ↑ cf. Hans Häckel: Meteorologie Volume 1338 from Uni-Taschenbücher M , UTB-Verlag, 2012, ISBN 978-382523700-4 , example 6.3.5. Die Föhnlage from April 1983 , p. 312 f ( restricted preview in the Google book search).
    Angela Schuh: Bioweather: how the weather affects our health. Volume 2416 by Beck'sche Reihe -     CH Beck Wissen , Verlag CH Beck , 2007, ISBN 978-340653616-8 , Typical weather situations , p. 34 ( limited preview in Google book search).
  4. ↑ Compare Austrian Society for Meteorology: Weather and Life , Volume 22, p. 167 ( limited preview in the Google book search).
  5. ↑ about 27./28. May 2008; Low Fei and Grit over the Bay of Biscay form a mighty high trough ; see map analysis 20080527 , 20080528 ; both met.fu-berlin.de;
    extreme southern exposure over the Alps ( foehn ), 30- to 40-year event; on the Gütsch ob Andermatt (2287 m) wind peaks 180 km / h, on the northern edge of the Alps and in the foothills of the Alps up to 30 ° C and tropical nights > 25 ° C; intense red sunsets on the 28th; Information from Andreas Hostettler, Stefan Bader: Föhnsturm and Saharasand 27./28. May 2008 ( Memento of the original from May 18, 2014 in the Internet Archive )     Info: The @1@ 2Template: Webachiv / IABot / www.meteoschweiz.admin.ch archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Meteo Switzerland, current weather events, meteoschweiz.admin.ch.
  6. ↑ Heinrich Faust, for example, describes the special case of cold air flowing in from the south-east: The structure of the earth's atmosphere: a summary, including the new rocket and satellite measurement results . Volume 127 of Die Wissenschaft , F. Vieweg, Braunschweig 1968, p. 68 ( limited preview in the Google book search).
    Compare also file: Cyclone Rebekka Nov 6 2000.jpg , an England     low with this effect