About SubX

The Subseasonal Experiment (SubX) is a two year MAPP/Climate Test Bed project focused on improving subseasonal predictions and providing a research dataset for the community to explore subseasonal predictability in leading modeling systems. It is supported through a partnership including NOAA Research’s Modeling, Analysis, Predictions, and Projections Program as well as the National Weather Service’s Office of Science and Technology Integration, the Office of Naval Research, and NASA. Multiple global models from NOAA, NASA, Environment Canada, the Navy, and the National Center for Atmospheric Research are producing 17 years of ensemble retrospective forecasts initialized weekly. Additionally, one-year of real-time predictions will be produced and provided to the NOAA/NWS Climate Prediction Center as additional guidance for their week 3-4 outlooks. Each modeling group follows a SubX Protocol for their reforecasts and real-time forecasts, which supports equal model comparison and robust skill assessment. The project will test the skill of individual prediction systems as well as multi-model combinations, and the data is available to both the research and operational communities.

The objectives of the SubX Project are:

  • Collecting and serving data both internally at CPC for use by operational forecasters and fore the external community via the IRI data library
  • Providing a baseline verification particularly for the weeks 3-4 temperature and precipitation probability forecasts
  • Evaluating the skill of individual model systems
  • Investigating multi-model combinations including selecting suitable models, optimizing the design of the system, and evaluation of the prediction products
  • Enhancing communications between operational forecasts and the model forecast producers
  • Participation in the NOAA/MAPP S2S Task Force

Prediction systems contributing to SubX

NOAA National Centers for Environmental Prediction


NOAA National Centers for Environmental Prediction


Environment Canada





Earth System Model

National Center for Atmospheric Research


NOAA Earth System Research Laboratory



Real-Time Predictions

SubX produces once-a-week real-time experimental forecasts for weeks 1-4 available to both the operational and research communities. These predictions provide NWS Climate Prediction Center (CPC) forecasters with additional models to experimentally guide their week 3-4 outlooks, which previously used only 1-3 models. The real-time predictions also allow researchers to better understand, diagnose, and address subseasonal prediction challenges.


COLA forecast maps:
Current SubX-based predictions of 2m temperature, precipitation, and 500 hPa geopotential height

Static Forecast Maps

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Interactive Forecasts

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Research Datasets

Get data here

Reforecast data over the period 1999-2015 and real-time predictions are available for research through the International Research Institute for Climate and Society (IRI) Data Library at Columbia University. The library is regularly updated as additional data becomes available.


Acknowledging SubX data

In order to document SubX data impact and enable continuing support, users of SubX data are expected to acknowledge SubX data and the participating modeling groups. The SubX model output should be referred to as “the SubX data” and referenced using the SubX DOI: 10.7916/D8PG249H

In publications, users should include a table (referred to below as Table XX) listing the models and institutions that provided model output used in the SubX system, as well as the digital object identifier of publications documenting the models. In addition, an acknowledgment similar to the following should be included in any publication:

    “We acknowledge the agencies that support the SubX system, and we thank the climate modeling groups (Environment Canada, NASA, NOAA/NCEP, NRL, and University of Miami) for producing and making available their model output. NOAA/MAPP, ONR, NASA, NOAA/NWS jointly provided coordinating support and led development of the SubX system.” where “Table XX” in the paper should list the models and modeling groups that provided the SubX data.

Besides the above acknowledgement, users should register any journal articles (or other scientific documents) that are based on SubX results. These terms of use will be published on the data dissemination site at the IRI.



Research Projects

The MAPP program, together with the NOAA Climate Test Bed, held a FY16 competitive research opportunity, which awarded funding to 5 projects that will work to develop an experimental multi-model subseasonal predictive capability. As part of their projects, the funded scientists participate in the MAPP Subseasonal to Seasonal Prediction Task Force, which also includes scientists funded through the FY16 MAPP competition "Research to Advance Prediction of Subseasonal to Seasonal Phenomena" as well as invited scientists from across the community with interest and expertise in the S2S prediction problem.

SubX research projects funded by the MAPP

Developing a Real-Time Multi-Model Sub-Seasonal Predictive Capability (SubX Core Team Proposal)

PI: Benjamin Kirtman (University of Miami);

Co-PIs: Kathy Pegion (GMU/COLA), Tim DelSole (GMU/COLA), Andrew Robertson (IRI/Columbia), Mike Tippett (IRI/Columbia), Robert Burgman (FIU), Hai Lin (Environment Canada), Jon Gottschalck (NOAA/CPC), Dan Collins (NOAA,CPC)

Estimating the Subseasonal Forecast Skill in the NASA GEOS-5 System with a Focus on the Madden Julian Oscillation and the Land Surface Memory Feedback Processes

PI: Deepthi Achuthavarier (NASA Goddard);

Co-PIs: Randal Koster (NASA Goddard), Jelena Marshak (NASA Goddard);

Collaborators: Dan Collins (NOAA/CPC), Jon Gottschalck (NOAA/CPC)

The Inclusion of Sub-Seasonal to Seasonal Predictions of the Navy’s Earth System Model in the North American Multi-Model Ensemble (NMME)

PI: Neil Barton (Naval Research Laboratory);

Co-PI: Joseph Metzger (NRL);

Collaborators: Dan Collins (NOAA/CPC), Jon Gottschalck (NOAA/CPC)

Sub-Seasonal Prediction with the CCSM4

PI: Benjamin Kirtman (University of Miami);

Co-PI: Kathy Pegion (GMU/COLA), Rong Fu (University of Texas at Austin);

Collaborators: Jon Gottschalck (NOAA/CPC), Dan Collins (NOAA/CPC)

An NCEP Global Ensemble Forecast System for Monthly Forecasts

PI: Yuejian Zhu (NOAA/EMC);

Co-PIs: Malaquías Peña (NOAA/EMC), Wei Li (NOAA/EMC), Xiaqiong Zhou (NOAA/EMC), Hong Guan (NOAA/EMC);

Collaborators: Dingchen Hou (NOAA/EMC), Richard Wobus (NOAA/EMC), Xu Li (NOAA/EMC), Qin Zhang (NOAA/CPC), Dan Collins (NOAA/CPC), Jon Gottschalck (NOAA/CPC)



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