Details:

Journal Title:
Atmosphere
Personal Author:
Overland, James E.;
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research); PMEL (Pacific Marine Environmental Laboratory);
OAR (Oceanic and Atmospheric Research); PMEL (Pacific Marine Environmental Laboratory); Less -
Description:
The extreme heat event that hit the Pacific Northwest (Oregon, Washington, southern British Columbia) at the end of June 2021 was 3 °C greater than the previous Seattle record of 39 °C; larger extremes of 49 °C were observed further inland that were 6 °C above previous record. There were hundreds of deaths over the region and loss of marine life and forests. At the large scale prior to the event, the polar vortex was split over the Arctic. A polar vortex instability center formed over the Bering Sea and then extended southward along the west coast of North America. The associated tropospheric trough (low geopotential heights) established a multi-day synoptic scale Omega Block (west-east oriented low/high/low geopotential heights) centered over the Pacific Northwest. Warming was sustained in the region due to subsidence/adiabatic heating and solar radiation, which were the main reasons for such large temperature extremes. The seasonal transition at the end of spring suggests the possibility of a southern excursion of a polar vortex/jet stream pair. Both the Pacific Northwest event in 2021 and the Siberian heatwave climax in June 2020 may be examples of crossing a critical state in large-scale atmospheric circulation variability.
Keywords:
[+]
Heat Waves (Meteorology)
Polar Vortex

Source:
Atmosphere, 12(11), 1434
Series:
PMEL contribution ; 5306;
DOI:
https://doi.org/10.3390/atmos12111434
Document Type:
Journal Article;
Place as Subject:
Northwest, Pacific;
Rights Information:
CC BY
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:2967462b4f067051110474e56ce8ce2d5992c7c6db7f83ad5fa4a38e751077e0
File Type:

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