The cyclone summaries are based on Tropical Cyclone Reports written by the NHC Hurricane Specialists, including the authors and Robert Berg, John L. Beven III, Eric Blake, Michael Brennan, Daniel Brown, John Cangialosi, Todd Kimberlain, and Richard Pasch. These reports are available online (http://www.nhc.noaa.gov/2011atlan.shtml). The forecast verification summary is based on Cangialosi and Franklin (2012) and is available online (http://www.nhc.noaa.gov/verification/pdfs/Verification_2011.pdf). The NWS Climate Prediction Center provided the climate-scale data for the 2011 season. Much of the local impact information contained in the individual storm summaries was provided by the meteorological services of the affected countries. In the United States, much of the local impact information is compiled by the local NWS Weather Forecast Offices. The NWS National Data Buoy Center and the National Ocean Service provided summaries for their data.
Cangialosi, J. P., and J. F. Franklin, 2012: 2011 National Hurricane Center forecast verification report. NOAA/NWS/NCEP/National Hurricane Center, 76 pp. [Available online at http://www.nhc.noaa.gov/verification/pdfs/Verification_2011.pdf.]
DeMaria, M., J. A. Knaff, and J. Kaplan, 2006: On the decay of tropical cyclone winds crossing narrow landmasses. J. Appl. Meteor. Climatol., 45, 491–499.
Dvorak, V. E., 1984: Tropical cyclone intensity analysis using satellite data. NOAA Tech. Rep. NESDIS 11, National Oceanic and Atmospheric Administration, Washington, DC, 47 pp.
Franklin, J. L., M. L. Black, and K. Valde, 2003: GPS dropwindsonde wind profiles in hurricanes and their operational implications. Wea. Forecasting, 18, 32–44.
Gray, W. M., 1984: Atlantic seasonal hurricane frequency. Part I: El Niño and 30-mb Quasi-Biennial Oscillation influences. Mon. Wea. Rev., 112, 1649–1668.
Harper, B. A., J. D. Kepert, and J. D. Ginger, 2009: Guidelines for converting between various wind averaging periods in tropical cyclone conditions. World Meteorological Organization, 64 pp.
Jarvinen, B. R., and C. J. Neumann, 1979: Statistical forecasts of tropical cyclone intensity for the North Atlantic basin. NOAA Tech. Memo. NWS NHC-10, 22 pp.
Knaff, J. A., M. DeMaria, B. Sampson, and J. M. Gross, 2003: Statistical, five-day tropical cyclone intensity forecasts derived from climatology and persistence. Wea. Forecasting, 18, 80–92.
Neumann, C. B., 1972: An alternate to the HURRAN (hurricane analog) tropical cyclone forecast system. NOAA Tech. Memo. NWS SR-62, 24 pp.
Office of the Federal Coordinator for Meteorology, 2010: National Hurricane Operations Plan. FCM-P12–2010, 10 pp. [Available online at http://www.ofcm.gov/nhop/10/nhop10.htm.]
Olander, T. L., and C. S. Velden, 2007: The advanced Dvorak technique: Continued development of an objective scheme to estimated tropical cyclone intensity using geostationary infrared satellite imagery. Wea. Forecasting, 22, 287–298.
Schott, T., and Coauthors, 2010: The Saffir–Simpson hurricane wind scale. National Weather Service, 4 pp. [Available online at http://www.nhc.noaa.gov/pdf/sshws.pdf.]
Simpson, R. H., 1974: The hurricane disaster potential scale. Weatherwise,27, 169 and 186.
Texas Tech University, 2006: A recommendation for an enhanced Fujita scale. 111 pp. [Available online at http://www.depts.ttu.edu/weweb/Pubs/fscale/EFScale.pdf.]
Velden, C., and Coauthors, 2006: The Dvorak tropical cyclone intensity estimation technique: A satellite-based method that has endured for over 30 years. Bull. Amer. Meteor. Soc., 87, 1195–1210.
These reports contain storm information omitted here because of limitations of space, including additional surface observations and a forecast and warning critique.
The nominal initial time represents the beginning of the forecast process. The actual advisory package is not released until 3 h after the nominal initial time (i.e., at 0300, 0900, 1500, and 2100 UTC).
For the remainder of this section, the term “tropical cyclone” shall be understood to also include subtropical cyclones.
Possible classifications in the best track are as follows: tropical depression, tropical storm, hurricane, subtropical depression, subtropical storm, extratropical, disturbance, wave, and low.
Special advisories are issued whenever an unexpected significant change has occurred or when watches or warnings are to be issued between regularly scheduled advisories. The treatment of special advisories in forecast databases changed in 2005 to the current practice of retaining and verifying the original advisory forecast.
This count does not include forecasts issued for systems later classified to have been something other than a tropical cyclone at the forecast time.
NHC extended its watch and warning lead times by 12 h starting in the 2010 season, such that a hurricane or tropical storm warning signifies that 1-min sustained tropical storm–force winds are expected to begin within the next 36 h. A watch now means those conditions are possible within the next 48 h.