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

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Met Office public forecast

http://www.metoffice.gov.uk/weather/tropicalcyclone/seasonal/northatlantic2013

Slightly more active than normal

0.41

0.42

0.42

Jo Camp

Method

• GloSEA5 (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)

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2013 North Atlantic Hurricane Season

• Statistical forecasts: CSU and TSR predict an active hurricane season

• Dynamical forecasts: ECMWF predict near-normal hurricane season.

Summary Table

S

S

D

D

Jo Camp

9

NOAAD

13-20 7-11 3-6

NOAA Hurricane seasonal outlook

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ENSO forecast

ECMWF GloSea5

Neutral conditions during ASOJo Camp

• CSU predict 72 % chance of MH landfallStatistical 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

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Tropical Storms: Eastern and Western North Pacific June-November 2013

• Near-average numbers of tropical storms predicted in the Western and Eastern North Pacific

• Forecast skill low

Western Pacific Eastern Pacific