Objectives of TIGGE• Facilitate all aspects of predictability research bycreating a permanent and easily accessible
archive of ensemble forecasts (=>support thescience of DAOS and PDP)
• Explore the added-value of multi-model
ensembles for forecasts of high-impact weather
1 to 15 days ahead (=>support the science ofSERA)• Enable a quick transition to an operational multimodel system in case sufficient added-value isproven (=>prepare the GIFS)• Harmonize as much as possible with TFSP
current efforts towards multi-model seasonalforecasts

Development in two phases• Phase-1: data collected in near-real time (via internet ftp) at asmall number of central TIGGE data archives. This can be
implemented now at little cost and could handle the estimated200 GB per day data volumes with current network andstorage capabilities• Phase-2: data archives distributed over a number ofrepositories, instead of all being held centrally, but efficientand transparent access to users will be maintained. This is amore flexible solution with the potential to eliminate routine
transfers of large data volumes. But this will require
substantial software development, in coordination with theWMO Information System, and will require additional funding

Achievements• Defined and agreed the concept of a common
database for global operational ensemble
forecasts, which will become a large research
infrastructure (S+T)• Agreed the content (S), the standardized formats,the architecture and the data access policy (T)• Finalized technical tests of data exchange (T)• Explored a number of options for extension of thedatabase content in the future (S)• Established initial contacts with TFSP and strong
relations with NAEFS (S)• Now seeking formal commitments from 10 data
providers (all the NWP centres running ensembleforecasts) and 3 archive and distribution centres (T)Priorities for the coming year
• Start accumulating data (summer) (T)• Start distributing data to scientists (autumn) (T)• Advertise the effort and the scientific opportunities offeredby TIGGE in a widely read journal (S)• Secure funding for Phase 2 (developing a sustainable,
distributed archive and distribution system) (S+T)• Set up a sub-group to standardize the contents and formats
of necessary initial and boundary data to enable forcing of
any LAM-EPS by any Global EPS (S+T)• Assess scientific issues of LAM-EPS (S, needs work fromother THORPEX WGs)
• Determine the extent of TIGGE support for the upcoming
demonstration projects (T)• Share technicalities of data exchanges with TFSP (T)Longer term objectives• Agree formats and content for TIGGE-LAM (2007)(S)• Agree common verification methods (S)• Organize TIGGE Users Workshop (end 2007 or 2008, withSERA) (S)• Develop and implement the concept of a point-to-point
exchange of initial and boundary conditions for LAM-EPS(2008) (T)• Technical transition to Phase 2 distributed data access, fullycompatible with the WIS (2009) (T)• Scientific evaluation of added-value of multi-model global
medium-range forecasts (2009) (S)• Subject to positive evaluation, transition to operational global
multi-model system (2009) (T)• Subject to positive evaluation, transition to operational
global+regional multi-model system (2011) (S+T)