Subject: 2013 Atlantic Hurricane Season Outlook: May 30 2013
From: David Rolph <[email-masked]>
To: All Staff International <[email-masked]>
Date: Thu, 30 May 2013 20:41:07 +0000

For those who might be planning travel this Summer/Fall or are otherwise interested, this circular from our insurance provider (Willis) indicates that even after 3 consecutive years with 19 named storms each year, we can expect little relief or change.  Should be another very active hurricane season (June through November).

David Rolph

Director of Global Security

Abt Associates

301-347-5684 (Office)

703-244-3672 (Cell)

2013 Atlantic Hurricane Season Outlook: May 30 2013

This seasonal forecast briefing is the first in a series to be released as new information becomes available. In this document, we provide an initial overview of how the season appears to be shaping up. Future briefings will provide more specific forecast information from additional organizations. The 2013 Atlantic hurricane season has a hard act to follow: 3 consecutive years with 19 named storms each. But because the major climate signals have not changed significantly this year, we have every reason to expect this run of high activity to continue into this season. Click here for more details.

Summary of 2013 Atlantic Seasonal Hurricane Forecasts

Data Source

Date

Issued

# Named Storms

(% of normal)

# Hurricanes (% of normal)

# Major Hurricanes

(% of normal)

ACE1

(% of normal)

1981-2010 Median Value

(Source CSU)

12.0

6.5

2.0

92

Average of 5 Analogue Years

(Source CSU)

Apr 10 2013

10.4   (87%)

7.2 (111%)

4.2 (210%)

151 (164%)

Colorado State University

Apr 10 2013

18.0 (150%)

9 (138%)

4 (200%)

165 (179%)

Tropical Storm Risk

Apr 5 2013

15.0 (125%)

8 (123%)

3 (150%)

131 (142%)

UK Met Office

May 20 2013

14.0 (117%)

9 (138%)

n/a

130 (141%)

Weather Services International

Apr 8 2013

16.0 (133%)

9 (138%)

5 (250%)

n/a

National Oceanic and Atmospheric Administration (NOAA)

May 23 2013

13 - 20 (108%

- 167%)

7 - 11 (108%

- 169%)

3 - 6 (150%

- 300%)

110 - 189 (120 %

- 205%)

NOAA/GFDL HyHuFS2

Mar 29 2013

n/a

8.4 (129%)

n/a

n/a

1Accumulated Cyclone Energy (ACE) is calculated as the sum of the square of the maximum wind speed in each 6-hour period during the life of a tropical cyclone from the time it reaches tropical storm strength (wind speeds ≥ 65 kmph (39 mph)) in units of 104; ACE = 10-4∑v2max, where v is measured in knots

2 The NOAA/GFDL hybrid (statistical-dynamical) hurricane forecast system is not an official outlook. This is a research product on the continued verification and evaluation of an experimental forecast system. NOAA/GFDL make these experimental forecast results available in order to facilitate and motivate research and discussion on the topic of long-lead seasonal hurricane forecasts.