Diagnosis of the Source and Evolution of Medium-Range Forecast Errors for Extratropical Cyclone JoachimSource: Weather and Forecasting:;2016:;volume( 031 ):;issue: 004::page 1197DOI: 10.1175/WAF-D-16-0026.1Publisher: American Meteorological Society
Abstract: edium-range forecasts for Cyclone Joachim, an extratropical cyclone that impacted western Europe on 16 December 2011, consistently predicted a high-impact intense cyclone; however, these forecasts failed to verify. The potential source and propagation of forecast errors for this case are diagnosed from the 51-member European Centre for Medium-Range Forecasts Ensemble Prediction System initialized 5 days prior to the cyclone?s landfall. Ensemble members are subdivided into two groups: one that contained the eight members that had the most accurate forecast of Joachim and, the other, the eight members that predicted the most intense cyclone. Composite differences between these two subgroups indicate that the difference between these forecasts originate in tropopause-based subsynoptic waves along a deep trough in the eastern Pacific. These errors move eastward over a northern stream ridge centered on the west coast of North America and modulate the evolution of a trough that dives equatorward out of Canada and is associated with the development of Joachim. Forecast error calculations and relaxation experiments indicate that reducing forecast errors associated with these subsynoptic features leads to more accurate forecasts. These results present further evidence that subsynoptic errors, especially those originating in the warm sector of a cyclone, can be a significant source of downstream forecast errors.
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contributor author | Lamberson, William S. | |
contributor author | Torn, Ryan D. | |
contributor author | Bosart, Lance F. | |
contributor author | Magnusson, Linus | |
date accessioned | 2017-06-09T17:37:21Z | |
date available | 2017-06-09T17:37:21Z | |
date copyright | 2016/08/01 | |
date issued | 2016 | |
identifier issn | 0882-8156 | |
identifier other | ams-88225.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4231982 | |
description abstract | edium-range forecasts for Cyclone Joachim, an extratropical cyclone that impacted western Europe on 16 December 2011, consistently predicted a high-impact intense cyclone; however, these forecasts failed to verify. The potential source and propagation of forecast errors for this case are diagnosed from the 51-member European Centre for Medium-Range Forecasts Ensemble Prediction System initialized 5 days prior to the cyclone?s landfall. Ensemble members are subdivided into two groups: one that contained the eight members that had the most accurate forecast of Joachim and, the other, the eight members that predicted the most intense cyclone. Composite differences between these two subgroups indicate that the difference between these forecasts originate in tropopause-based subsynoptic waves along a deep trough in the eastern Pacific. These errors move eastward over a northern stream ridge centered on the west coast of North America and modulate the evolution of a trough that dives equatorward out of Canada and is associated with the development of Joachim. Forecast error calculations and relaxation experiments indicate that reducing forecast errors associated with these subsynoptic features leads to more accurate forecasts. These results present further evidence that subsynoptic errors, especially those originating in the warm sector of a cyclone, can be a significant source of downstream forecast errors. | |
publisher | American Meteorological Society | |
title | Diagnosis of the Source and Evolution of Medium-Range Forecast Errors for Extratropical Cyclone Joachim | |
type | Journal Paper | |
journal volume | 31 | |
journal issue | 4 | |
journal title | Weather and Forecasting | |
identifier doi | 10.1175/WAF-D-16-0026.1 | |
journal fristpage | 1197 | |
journal lastpage | 1214 | |
tree | Weather and Forecasting:;2016:;volume( 031 ):;issue: 004 | |
contenttype | Fulltext |