2013 North Atlantic hurricane seasonal forecast Ray Bell

2013 North Atlantic hurricane seasonal forecast Ray Bell with thanks to Joanne Camp (met office)

TS has surface wind speeds > 17 m/s (39 mph) H > 33 m/s (74 mph)

• 3 consecutive years of 19 TS. • Active hurricane period that began in 1995 averaged 15 TS, 8 H and 4 MH

Met Office public forecast 0. 42 0. 41 Slightly more active than normal Jo Camp http: //www. metoffice. gov. uk/weather/tropicalcyclone/se asonal/northatlantic 2013 © Crown copyright Met Office 0. 42

Method • Glo. SEA 5 (42 members) • ECMWF System 4 (41 members) • A Simple tracking algorithm (mean sea level pressure based). • TS, H and ACE calibrated with previous years (hindcasts)

2013 North Atlantic Hurricane Season Summary Table S S D D D 9 NOAA 13 -20 7 -11 3 -6 • Statistical forecasts: CSU and TSR predict an active hurricane season • Dynamical forecasts: ECMWF predict near-normal hurricane season. Jo Camp © Crown copyright Met Office

NOAA Hurricane seasonal outlook

ENSO forecast ECMWF Neutral conditions during ASO © Crown copyright Met Office Glo. Sea 5 Jo Camp

• CSU predict 72 % chance of MH landfall Statistical relation between seasons activity and landfalling in previous years. • Land major hurricane landfall Hurricane Wilma 2005 (longest since 1900) • NOAA – realtime doppler radar on Hurricane hunters which will be used in upgraded HWRF Intensity forecast

EPAC forecast • below-normal hurricane season (11 - 16 TS) 15 (5 – 8 H) 8 (1 – 4 MH) 4

CPAC forecast • below-normal hurricane season (1 - 3 TS) 4 -5

Tropical Storms: Eastern and Western North Pacific June-November 2013 Western Pacific Eastern Pacific • Near-average numbers of tropical storms predicted in the Western and Eastern North Pacific • Forecast skill low © Crown copyright Met Office