Synoptic Analysis of Cold Air Outbreaks over the California Central Valley

Synoptic Analysis of Cold Air Outbreaks over the California Central Valley AbstractHow does extreme cold air reach the California Central Valley (CCV) and most of the US west coast? We answer this question using composite patterns for the ten coldest cold air outbreaks (CAOs) to reach the CCV during 1979-2013. While unusually cold air over California occurs in all events by design, how it arrives there is complicated and varies. The only other feature present in all events for several days prior to CAO onset is unusually strong surface high pressure in and south of the Gulf of Alaska. This high has low level cold air on its west side and a deep layer of cold air moving southward on its east side. Cold air aloft flows parallel to the North American west coast and sinks as it approaches the CCV. Farther west, warm advection builds a ridge aloft. The large scale meteorological pattern (LSMPs) are equivalent-barotropic. The LSMP’s ridge over Alaska, trough near California, and ridge over the southeastern US appear in all cases by onset and is similar to the Pacific-North American teleconnection pattern. Cross sections show cold air flowing from the continental interior consistent with a strong pressure gradient created by extreme cold in the continental interior. Where and when the interior cold and surface flow occurs varies between events. A geopotential trough associated with that cold air aloft passes over the CCV before onset fostering sinking behind that is reinforced by the cold air advection below. Though sinking, as a locally-defined anomaly, the cold intensifies as it migrates from the polar region to the climatologically warmer CCV. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Climate American Meteorological Society

Synoptic Analysis of Cold Air Outbreaks over the California Central Valley

Journal of Climate , Volume preprint (2017): 1 – Sep 5, 2017

Loading next page...
 
/lp/ams/synoptic-analysis-of-cold-air-outbreaks-over-the-california-central-gwwT72bmBd
Publisher
American Meteorological Society
Copyright
Copyright © American Meteorological Society
ISSN
1520-0442
D.O.I.
10.1175/JCLI-D-17-0167.1
Publisher site
See Article on Publisher Site

Abstract

AbstractHow does extreme cold air reach the California Central Valley (CCV) and most of the US west coast? We answer this question using composite patterns for the ten coldest cold air outbreaks (CAOs) to reach the CCV during 1979-2013. While unusually cold air over California occurs in all events by design, how it arrives there is complicated and varies. The only other feature present in all events for several days prior to CAO onset is unusually strong surface high pressure in and south of the Gulf of Alaska. This high has low level cold air on its west side and a deep layer of cold air moving southward on its east side. Cold air aloft flows parallel to the North American west coast and sinks as it approaches the CCV. Farther west, warm advection builds a ridge aloft. The large scale meteorological pattern (LSMPs) are equivalent-barotropic. The LSMP’s ridge over Alaska, trough near California, and ridge over the southeastern US appear in all cases by onset and is similar to the Pacific-North American teleconnection pattern. Cross sections show cold air flowing from the continental interior consistent with a strong pressure gradient created by extreme cold in the continental interior. Where and when the interior cold and surface flow occurs varies between events. A geopotential trough associated with that cold air aloft passes over the CCV before onset fostering sinking behind that is reinforced by the cold air advection below. Though sinking, as a locally-defined anomaly, the cold intensifies as it migrates from the polar region to the climatologically warmer CCV.

Journal

Journal of ClimateAmerican Meteorological Society

Published: Sep 5, 2017

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off