Climate Prediction Center (CPC) Northern and Southern Hemisphere Blocking Index

Metadata Updated: January 17, 2017

Atmospheric blocking is commonly referred to as the situation when the normal zonal flow is interrupted by strong and persistent meridional flow. The normal eastward progression of synoptic disturbances is obstructed leading to episodes of prolonged extreme weather conditions. On intraseasonal time scales the persistent weather extremes can last from several days up to a few weeks, often accompanied by significant temperature and precipitation anomalies. Numerous definitions of blocking exist in the literature and all involve a level if subjectivity. We use the blocking index of Tibaldi and Molteni (1990) modified from that of Lejenas and Okland (1983). This product displays the daily observed blocking index for the past 3 months up to and including the present day. Additionally, outlookss of the blocking index and the 500 hPa geopotential height field anomalies are generated form the NCEP Global Forecast System (GFS) model. The outlooks mare displayed for days 1-9 for both the northern and southern Hemispheres. The product is not archived so a historical time series is not available. To produce a time series it is recommended that the methodology of Tibaldi and Molteni (1990) be applied using the reanalysis dataset of choice. Blocking frequency over the 1950-2000 time period and composites as a function of ENSO phase are also provided.

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Dates

Metadata Date March 17, 2013
Metadata Created Date September 27, 2015
Metadata Updated Date January 17, 2017
Reference Date(s) January 1, 2004 (publication)
Frequency Of Update daily

Metadata Source

Harvested from NOAA CSW Harvest Source

Graphic Preview

The daily blocking index is part of the Climate Prediction Center (CPC) Teleconnections Products Suite. The daily blocking index is created from the NCEP/NCAR Reanalysis over the last 90 days up to and including the current day. 500 hPa geopotential height from the NCEP Global Forecast System (GFS) is used to produce the outlooks blocking index in the northern and southern hemispheres.

Additional Metadata

Resource Type Dataset
Metadata Date March 17, 2013
Metadata Created Date September 27, 2015
Metadata Updated Date January 17, 2017
Reference Date(s) January 1, 2004 (publication)
Responsible Party Climate Prediction Center, NOAA (Point of Contact)
Contact Email
Access Constraints Access Constraints: None Use Constraints: Acknowledgment of the Data Originator when using the data item as a source. Distribution Liability: The user assumes the entire risk related to its use of this data. NWS is providing this data "as is," and NWS disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose. In no event will NWS be liable to you or to any third party for any direct, indirect, incidental, consequential, special or exemplary damages or lost profit resulting from any use or misuse of this data. As required by 17 U.S.C. 403, third parties producing copyrighted works consisting predominantly of the material appearing in NWS Web pages must provide notice with such work(s) identifying the NWS material incorporated and stating that such material is not subject to copyright protection. Refer the NOAA National Weather Service disclaimer; http://www.weather.gov/disclaimer.php
Bbox East Long 179.75
Bbox North Lat 89.75
Bbox South Lat -89.75
Bbox West Long -179.75
Coupled Resource
Frequency Of Update daily
Graphic Preview Description The daily blocking index is part of the Climate Prediction Center (CPC) Teleconnections Products Suite. The daily blocking index is created from the NCEP/NCAR Reanalysis over the last 90 days up to and including the current day. 500 hPa geopotential height from the NCEP Global Forecast System (GFS) is used to produce the outlooks blocking index in the northern and southern hemispheres.
Graphic Preview File http://www.cpc.ncep.noaa.gov/products/precip/CWlink/blocking/real_time_nh/1panel_ghgs_obs_nh_nrm.gif
Graphic Preview Type GIF
Guid gov.noaa.cpc: CPC-BLOCKING-DLY-BLOCKINDEX-v2004
Harvest Object Id 33d6d5be-6d40-43d8-a6d1-bd8377ba9c0b
Harvest Source Id 2aed8e29-fc5b-4cde-aa66-fb1118fd705e
Harvest Source Title NOAA CSW Harvest Source
Licence
Metadata Language
Metadata Type geospatial
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 2004-01-01
Temporal Extent End 2014-08-25T10:50:05.41-04:00

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