Climate Forecast Applications Network (CFAN)

TROPICAL CYCLONE FORECAST PRODUCTS

CFAN’s tropical weather research team incorporates the best weather prediction models, leading edge research, and state-of-the-art forecasting techniques into our tropical cyclone forecasting system. CFAN translates the world-leading research of the Tropical Meteorology and Climate Dynamics Group at the Georgia Institute of Technology into tropical cyclone forecast products that are unique in the marketplace. CFAN has created an advanced tropical forecasting solution that includes extended range probabilistic forecasts out to fifteen days, monthly outlooks of track density anomalies and landfall risk and probability, and integration with decision support processes. Starting in 2007, CFAN’s founders decided to translate their advanced tropical cyclone related research into market-oriented solutions, with the commencement of operational forecasts of North Atlantic hurricanes. CFAN has continued to evolve the quality, sophistication and breadth of its tropical cyclone forecast product. While the initial focus was with the energy sector, starting with the 2012 Atlantic hurricane season, CFAN is making its tropical cyclone forecasts available to a broader clientele. CFAN’s extended range tropical cyclone forecasts (1-32 days) can support decision making in a wide array of sectors including: offshore resource operation and safety, energy demand impact, insurance and reinsurance needs, risk management planning, emergency management disaster planning and mitigation, shipping implications and rerouting, utilities operations and recovery, logistics planning, travel and tourism impacts, supply chain interruption and restoration, among others. CFAN’s tropical cyclone forecast products are based on a sophisticated analysis of the ECMWF Variable Ensemble Prediction System 1-15day and monthly forecast products (16-32 days) that is integrated into a multi-model analysis with forecasts from other global and regional models. CFAN’s probabilistic forecasts of Atlantic tropical cyclone tracks and intensity consistently outperform both government and market forecasts beyond a 3 day time horizon, showing track skill within 300 miles out to 7 days (even before the tropical cyclones actually form). CFAN’s unique tropical cyclogenesis model has demonstrated skill 3-7 days in advance for predicting the formation of tropical cyclone associated with African Easterly Waves, and skill 7-10 days in the North Indian Ocean. The end result is forecasts that allow advance notification and planning as well as quicker response for those who utilize the CFAN solution. The following describes some of the advanced techniques developed and refined by CFAN’s research team for use in operational forecasts. Tropical cyclone track forecasts: CFAN’s tropical cyclone identification and bias-corrected tracking scheme is applied to each of the 51 unique ensemble members of the ECMWF forecast. This allows for the creation of more reliable probabilistic track density forecasts and a dynamic cone of uncertainty at a basin-wide level. Ensemble clustering techniques are used to identify the highest probability track of both pre-genesis and existing tropical cyclones. A multi-model ensemble track density analysis is enabled by an interactive tool that allows the user to select track groupings from available model forecasts.

Example of Tropical Cyclone Track and Probability Forecasts

Climate Forecast Applications Network (CFAN)

Tropical cyclogenesis risk analysis: The ability to forecast the formation (genesis) of tropical cyclones enables extended-range tropical cyclone forecasts. Understanding the behavior of active tropical cyclones is certainly important, but there is great value in awareness of tropical cyclone formation risks, particularly for events likely to form near coastlines. CFAN employs a Bayesian-based genesis risk approach using ECMWF forecast products and utilizing historical analysis of the large-scale environment under which tropical cyclones have formed. This allows for assigning formation exposure risk for key regions throughout a forecast basin.

African Easterly Wave detection and forecast: Recognizing that African Easterly Waves (AEWs) account for 85% of major hurricanes in the North Atlantic, it is clear that a better understanding of these meteorological events is paramount in disaster and risk avoidance and mitigation. CFAN has developed an advanced tracking system for AEWs that allows for forecasting the evolution of these events even before they leave Africa. Recent CFAN research has demonstrated that producing tropical cyclone forecasts beyond a one week time horizon is strongly correlated to the predictability of African Easterly Wave development and their tracks.

Example of African Easterly Wave Tracking

Probabilistic tropical cyclone intensity and hurricane damage functions: Utilizing CFAN’s multi-model ensemble forecasts, we are able to give forecast users a better understanding of the potential for impact from a given tropical cyclone. CFAN produces ensemble-based probabilistic forecasts of the evolution of tropical cyclone intensity, by applying an intensity model calibration to each ensemble track. CFAN’s forecast of tropical cyclone size is unique in the marketplace, enabling improved predictions of landfall damage not just based on intensity, but also horizontal size and translation speed. Combining this information with storm surge, wind exposure, rain extremes and post landfall tornado risk allows for more thorough risk assignment for each tropical cyclone and impact region.

Tropical cyclone risk beyond 15 days: Utilizing the ECMWF’s monthly ensemble forecasting system, CFAN is applies a modified version of its enhanced tropical cyclone tracking scheme to create forecasts out to 32 days. This product identifies areas of tropical cyclone activity and landfall risk during the extended outlook period and also in comparison with climatology. To further enhance the forecast, CFAN provides a forecast confidence utilizing a technique based upon the strong relationship between tropical cyclone activity and the Madden Julian Oscillation.

Climate Forecast Applications Network (CFAN)

Example of Monthly Tropical Cyclone Outlook

CFAN’s tropical cyclone Dashboard is a user-friendly web interface customizable for each client. Daily forecast reports are provided by CFAN’s tropical cyclone forecast team tailored to the client’s specified risk and may be distributed via e-mail and text messaging. Our Dashboard is designed to provide the essential, decision-oriented information and summaries immediately upon entry to the tropical cyclone page. This information is supported by in depth analysis and graphics available via single direction scrolling that makes getting to all components of the product as simple as possible. We have incorporated into our tropical cyclone dashboard a variety of user-selected features that include animation sequences, graphics sliders, overlays, and zoom capabilities. These features and their inherent flexibility allow a range of users to gain quick access to the inputs that are critical in meeting their individual decision needs.

CFAN Tropical Cyclone Dashboard

Climate Forecast Applications Network (CFAN)

Following is a sampling of recent peer-reviewed publications, reports, and conference proceedings illustrating our team’s seminal contributions to tropical cyclone research and forecasting:

Belanger, JI, PJ Webster, JA Curry, MT Jelinek, 2012: Extended Prediction of North Indian Ocean

Tropical Cyclones. Weather and Forecasting, in press. Belanger, JI, PJ Webster, MT Jelinek, JA Curry, 2012: Tropical Cyclone Forecast and Warning

System for the North Indian Ocean, Indian Ocean Tropical Cyclone Conference 2012 Webster, PJ, Belanger JI, PJ Webster, JA Curry, MT Jelinek, 2012: Extended Prediction of North

Indian Ocean Tropical Cyclones Using the ECMWF Variable Ensemble Prediction System, Indian Ocean Tropical Cyclone Conference 2012

Curry JA, M Jelinek, 2011: Assessment of strategies to project U.S. landfalling hurricanes. Report prepared for Guy Carpenter.

Agudelo, PA, CD Hoyos, JA Curry, PJ Webster, 2011: Probabilistic discrimination between large-scale environments of intensifying and decaying African Easterly Waves. Climate Dynamics, 36, 1379-1401

Kim, HJ, PJ Webster, JA Curry, 2011: Modulation of North Pacific Tropical Cyclone Activity by Three Phases of Enso. J. Climate, 24, 1839-1849.

Done, J., GJ Holland, A. Suzuki and PJ Webster, 2011: The role of wave accumulation in tropical cyclone genesis over the tropical North Atlantic. Climate Dynamics, 36, 753-767

Belanger, JI, MT Jelinek, JA Curry, PJ Webster, 2011: The New Frontier: Operational Tropical Cyclone Forecasts Beyond Five Days, American Meteorological Society Annual Conference 2011

Jelinek, MT, JI Belanger JA Curry, PJ Webster, 2011: Adaptive Forecasting - Improving End User Understanding of Tropical Cyclones, American Meteorological Society Annual Conference 2011

Belanger, JI, JA Curry, PJ Webster, 2010: Predictability of North Atlantic Tropical Cyclone Activity on Intraseasonal Timescales. Mon. Wea. Rev., 138, 4362-4374.

Kim, HM, PJ Webster, 2010: Extended-range seasonal hurricane forecasts for the North Atlantic with a hybrid statistical/dynamical model. Geophys. Res. Lett., 37, Article No L21705 Holland, G., JI Belanger, A2010: A revised radial wind model for hurricanes. Mon. Wea. Rev., 138,

4393-4401. Belanger, JI, JA Curry, CD Hoyos, 2009: Variability in tornado frequency associated with U.S.

landfalling tropical cyclones. Geophys. Res. Lett., 36, L17805 Kim, HM, PJ Webster and JA Curry, 2009: Impact of shifting patterns of Pacific Ocean warming on

the frequency and tracks of North Atlantic tropical cyclones. Science, 325, 77-80

Interested in learning more about CFAN’s tropical cyclone forecast solutions? Judith Curry, curryja@cfanclimate.com, 404.803.2012