WORLD METEOROLOGICAL ORGANIZATION
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TCM-8/Doc. 4.3.2
(23.X.2015)
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EIGHTH TROPICAL CYCLONE RSMCs/TCWCs
TECHNICAL COORDINATION MEETING
ITEM 4.3.2
MIAMI, FLORIDA, USA
2 TO 6 NOVEMBER 2015
ENGLISH ONLY
IMPACT-BASED TROPICAL CYCLONE FORECASTING
AND WARNING SERVICES WITH MULTI-HAZARD APPROACH
(Submitted by the Secretariat)
Summary and Purpose of Document
This document focuses on the enhancement on the capacities of Members to
provide more accurate forecasting and warning services which are impactbased and in multi-hazard approach (which is also a decision of EC-66).
ACTION PROPOSED
The meeting is invited to discuss and recommend ways to

Enhance the capacities of Members to provide more accurate forecasting and warning
services which are impact-based and in multi-hazard approach, and propose activities
to promote such an endeavor.
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Appendix: The Decisions of the 17th WMO Congress.
Reference: Abridged final report with resolutions of the Seventeenth World Meteorological
Congress, Geneva, 25 May–12 June 2015 (WMO-No. 1157)
TCM-8/Doc. 4.3.2, APPENDIX
The Decisions of the 17th WMO Congress
The WMO publication WMO-No. 1157 – Abridged final report with resolutions of the Seventeenth
World Meteorological Congress contains the following paragraphs that are requested to
implement:
Service delivery through Impact-Based Forecasting and Risk-Based Warning
3.1.4 Congress recognized that understanding disaster risk and forecasting hydrometeorological
impacts is generally beyond the remit of meteorologists and hydrologists and that the complexity of
issues related to impact-based forecasting and risk-based warning requires planning and forging of
partnerships at many levels and with many other government agencies, scientific institutions and
stakeholders. It noted that the Executive Council had discussed this issue in the provision of public
weather and warning services in support of social and economic resilience, and that the
Commission for Basic Systems (CBS), at its extraordinary session (CBSExt.(2014), September
2014) had approved a set of guidelines for Members on this subject (ref.:paragraphs 3.1.34-3.1.62).
3.1.5 Congress agreed that in order to implement impact-based forecasting and risk-based
warning successfully, it was necessary for Members to include these practices in future
modernization programmes, to develop new skills in NMHSs and other involved institutions, to
develop effective partnerships among a diverse group of stakeholders providing the necessary
information for impact-based forecasting, to cross-train staff of NMHSs and emergency responders,
and to develop operational pilot projects as a basis of developing national and regional capacities
to institute these practices. Congress requested the Secretary-General to provide assistance as
required to Members in their efforts to move towards impact-based and user-tailored forecasting
and risk-based warning practices.
Delivery of Impact-based Forecasts and Warnings
3.1.42 Congress acknowledged that each year the impacts of severe hydrometeorological hazards
cause multiple casualties as well as significant loss and damage to property and infrastructure.
These hazards have adverse economic consequence for communities, in spite of the fact that
many of these severe events had been well forecast, with accurate warning information
disseminated by the responsible NMHSs. The reasons for this apparent disconnect lie in the gap
between forecasts and warnings of hydrometeorological events and an understanding of their
potential impacts, both by the authorities responsible for civil protection/emergency management
and by the population at large. Closing this gap, and improving the understanding of the potential
impacts of severe hydrometeorological events poses a challenge to NMHSs and their partner
agencies, particularly Disaster Reduction and Civil Protection Agencies (DRCPAs). Progressing
from weather forecasts and warnings to multi-hazard impact-based forecast and warning services
represents a paradigm shift in service delivery for many NMHSs, but a necessary step to enable
those at risk take appropriate action to avoid harm. Congress agreed that historically, all NMHSs
have featured forecasting of the weather as central to their mission, and most also issue weather
warnings in the case where hazardous weather is expected. In the case of both weather forecasts
and warnings, the focus is on what the weather will be. It is now advocated that this weather-based
paradigm evolve to one, which is focused primarily on forecasting impacts. In other words, the
focus should evolve to what the weather will do. Impact-based forecasts and warnings should be
accurate and understandable and be delivered in a timely manner.
3.1.43 Congress recognized the merit of advancing toward this paradigm shift, despite the
complexity of impact-based forecasting and risk-based warnings, and supported the outcome of
discussions at EC-66 on this approach. It welcomed the preparation of the WMO Guidelines on
Multi-hazard Impact-based Forecast and Warning Services by PWS experts and its publication
following approval by the extraordinary session of CBS (CBS-Ext.(2014)). Congress encouraged
the use of these Guidelines by Members in the preparation in moving towards impact-based
practices in their respective NMHSs.
TCM-8/Doc. 4.3.2, APPENDIX, p. 2
3.1.44 Congress welcomed the initiative by the PWS Programme to launch a pilot project in
Mozambique on the implementation of impact-based forecasting and warning to test the
application of principles contained in the Guidelines. The project will focus on developing effective
partnerships among various stakeholders; collection of data necessary for impact-based services;
and training of the staff of partner agencies on new skills in delivering impact-based information
services. Congress requested the Secretary-General to initiate similar projects, within available
resources, in other regions with the eventual aim of assisting Members to mainstream impactbased forecasting and warning services into their operations.
3.1.96 Congress recalled Resolution 23 (Cg-XVI) – Tropical Cyclone Programme. It emphasized
that the establishment of an effective warning system through a multidisciplinary and impact-based
approach was a high priority requirement for reducing the social-economic impacts of tropical
cyclones, and that implementation of the TCP should be guided by the WMO Strategy for Service
Delivery, and should comply with the WMO Strategic Plan, especially WMO strategic priorities on
DRR and Capacity Development. Congress requested the Secretary-General to enhance the
contribution of the TCP to DRR services delivery through the implementation of impact-based
monitoring, forecasting and risk-based warnings as well as through enhanced coordination of the
TCP with other technical programmes. Congress also recognized that effective partnerships with
disaster management authorities and other relevant national and regional agencies could also
facilitate contribution to DRR services delivery.
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