Why Do DJF 2023/24 Upper‐Level 200‐hPa Geopotential Height Forecasts Look Different From the Expected El Niño Response?

Abstract We investigate why the North American Multi‐Model Ensemble (NMME) upper‐level height forecast for December–February (DJF) 2023/24 differs from the expected El Niño response. These atypical height anomalies emerged despite the fact a strong El Niño was forecast. The analysis focuses on diagn...

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Main Authors: Mingyue Chen, Arun Kumar, Michelle L’Heureux, Peitao Peng, Tao Zhang, Martin P. Hoerling, Henry F. Diaz
Format: Article
Language:English
Published: Wiley 2024-07-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2024GL108946
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author Mingyue Chen
Arun Kumar
Michelle L’Heureux
Peitao Peng
Tao Zhang
Martin P. Hoerling
Henry F. Diaz
author_facet Mingyue Chen
Arun Kumar
Michelle L’Heureux
Peitao Peng
Tao Zhang
Martin P. Hoerling
Henry F. Diaz
author_sort Mingyue Chen
collection DOAJ
description Abstract We investigate why the North American Multi‐Model Ensemble (NMME) upper‐level height forecast for December–February (DJF) 2023/24 differs from the expected El Niño response. These atypical height anomalies emerged despite the fact a strong El Niño was forecast. The analysis focuses on diagnosing the NMME forecasts of DJF 2023/24 for SSTs and 200‐hPa heights initialized at the beginning of November 2023 relative to other ensemble mean NMME DJF forecasts dating back to 1982. The results demonstrate that forecasts of the 200‐hPa height anomalies had a large contribution from warming trends in global SSTs. It is the combination of trends and the expected El Niño teleconnection that results in the forecast height anomalies. Increasingly, for forecasts of geopotential height anomalies during the recent El Niño winters, the amplitude of trends is nearly equal to the signal from El Niño and has implications for the climatological base period selection for seasonal forecasts.
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series Geophysical Research Letters
spelling doaj-art-5ea12b3acd6b44049aed0cdd9b52255e2025-08-20T03:49:46ZengWileyGeophysical Research Letters0094-82761944-80072024-07-015114n/an/a10.1029/2024GL108946Why Do DJF 2023/24 Upper‐Level 200‐hPa Geopotential Height Forecasts Look Different From the Expected El Niño Response?Mingyue Chen0Arun Kumar1Michelle L’Heureux2Peitao Peng3Tao Zhang4Martin P. Hoerling5Henry F. Diaz6NOAA/NWS/NCEP/Climate Prediction Center College Park MD USANOAA/NWS/NCEP/Climate Prediction Center College Park MD USANOAA/NWS/NCEP/Climate Prediction Center College Park MD USANOAA/NWS/NCEP/Climate Prediction Center College Park MD USANOAA/NWS/NCEP/Climate Prediction Center College Park MD USADepartment of Civil and Environmental Engineering University of Colorado‐Boulder Boulder CO USADepartment of Geography and Environment University of Hawaii at Manoa Honolulu HI USAAbstract We investigate why the North American Multi‐Model Ensemble (NMME) upper‐level height forecast for December–February (DJF) 2023/24 differs from the expected El Niño response. These atypical height anomalies emerged despite the fact a strong El Niño was forecast. The analysis focuses on diagnosing the NMME forecasts of DJF 2023/24 for SSTs and 200‐hPa heights initialized at the beginning of November 2023 relative to other ensemble mean NMME DJF forecasts dating back to 1982. The results demonstrate that forecasts of the 200‐hPa height anomalies had a large contribution from warming trends in global SSTs. It is the combination of trends and the expected El Niño teleconnection that results in the forecast height anomalies. Increasingly, for forecasts of geopotential height anomalies during the recent El Niño winters, the amplitude of trends is nearly equal to the signal from El Niño and has implications for the climatological base period selection for seasonal forecasts.https://doi.org/10.1029/2024GL108946multi‐model ensemble meanseasonal forecastEl Niño—Southern OscillationSST warming trendupper‐level height
spellingShingle Mingyue Chen
Arun Kumar
Michelle L’Heureux
Peitao Peng
Tao Zhang
Martin P. Hoerling
Henry F. Diaz
Why Do DJF 2023/24 Upper‐Level 200‐hPa Geopotential Height Forecasts Look Different From the Expected El Niño Response?
Geophysical Research Letters
multi‐model ensemble mean
seasonal forecast
El Niño—Southern Oscillation
SST warming trend
upper‐level height
title Why Do DJF 2023/24 Upper‐Level 200‐hPa Geopotential Height Forecasts Look Different From the Expected El Niño Response?
title_full Why Do DJF 2023/24 Upper‐Level 200‐hPa Geopotential Height Forecasts Look Different From the Expected El Niño Response?
title_fullStr Why Do DJF 2023/24 Upper‐Level 200‐hPa Geopotential Height Forecasts Look Different From the Expected El Niño Response?
title_full_unstemmed Why Do DJF 2023/24 Upper‐Level 200‐hPa Geopotential Height Forecasts Look Different From the Expected El Niño Response?
title_short Why Do DJF 2023/24 Upper‐Level 200‐hPa Geopotential Height Forecasts Look Different From the Expected El Niño Response?
title_sort why do djf 2023 24 upper level 200 hpa geopotential height forecasts look different from the expected el nino response
topic multi‐model ensemble mean
seasonal forecast
El Niño—Southern Oscillation
SST warming trend
upper‐level height
url https://doi.org/10.1029/2024GL108946
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