Block (meteorology)

An example of an omega block over western North America in May 2006

Blocks in meteorology are large-scale patterns in the atmospheric pressure field that are nearly stationary, effectively "blocking" or redirecting migratory cyclones. They are also known as blocking highs or blocking anticyclones.[1] These blocks can remain in place for several days or even weeks, causing the areas affected by them to have the same kind of weather for an extended period of time (e.g. precipitation for some areas, clear skies for others).[2] In the Northern Hemisphere, extended blocking occurs most frequently in the spring over the eastern Pacific and Atlantic Oceans.[1] Whilst these events are linked to the occurrence of extreme weather events such as heat waves,[3] particularly the onset and decay of these events is still not well captured in numerical weather forecasts and remains an open area of research.[4][5]

  1. ^ a b Glossary of Meteorology, Second Edition; American Meteorological Society, 2000; ISBN 1-878220-34-9.
  2. ^ "The Omega Block". theweatherprediction.com. Archived from the original on 6 December 2017. Retrieved 27 July 2019.
  3. ^ Stefanon, Marc; D’Andrea, Fabio; Drobinski, Philippe (2012-03-01). "Heatwave classification over Europe and the Mediterranean region". Environmental Research Letters. 7 (1): 014023. Bibcode:2012ERL.....7a4023S. doi:10.1088/1748-9326/7/1/014023. ISSN 1748-9326.
  4. ^ Woollings, Tim; Barriopedro, David; Methven, John; Son, Seok-Woo; Martius, Olivia; Harvey, Ben; Sillmann, Jana; Lupo, Anthony R.; Seneviratne, Sonia (2018-09-01). "Blocking and its Response to Climate Change". Current Climate Change Reports. 4 (3): 287–300. Bibcode:2018CCCR....4..287W. doi:10.1007/s40641-018-0108-z. ISSN 2198-6061. PMC 6428232. PMID 30956938. Archived from the original on 2023-09-16. Retrieved 2022-04-07.
  5. ^ Lupo, Anthony R. (November 2021). "Atmospheric blocking events: a review". Annals of the New York Academy of Sciences. 1504 (1): 5–24. Bibcode:2021NYASA1504....5L. doi:10.1111/nyas.14557. ISSN 0077-8923. PMID 33382135. S2CID 229931718. Archived from the original on 2023-09-16. Retrieved 2022-04-07.