THE ATLANTIC HURRICANE SEASON FORECAST – 2013

3 06 2013

| By Dale C. S. Destin

The Forecast

The general consensus among tropical cyclone experts is for an above normal Atlantic Hurricane Season for 2013. The consensus forecast calls for 16 named storms, 9 hurricanes and 4 major hurricanes. A normal season averages of 12.1 named storms, 6.4 hurricanes and 2.7 major hurricanes (See table 1). The science behind the outlook is rooted in the analysis and prediction of current and future global climate patterns as compared to previous seasons with similar conditions. For this season, the experts are citing a warmer than normal Tropical North Atlantic as the main reason for an above normal season prediction.

AtlanticHurricaneSeasonForecasts2013What does this mean for Antigua and Barbuda?

Although there have been great advancements in the science of tropical cyclone (depression, tropical storm and hurricane), the science has not yet reached the stage where accurate predictions can be made of how many cyclones will form in a given year. Also, the science cannot accurately predict when and where these systems will move or make landfall months in advance. The details of the large-scale weather patterns that direct the path of these cyclones cannot be predicted more than a few days into the future. However, for the current active era (1995 – present), there is around a 39% chance or 4 in 10 chances of one or more hurricanes affecting Antigua (directly or indirectly) this season; this is around 10% above the long term chance.

The 2012 Hurricane Season

The 2012 Atlantic Hurricane Season produced nineteen (19) named storms. Of the nineteen (19) storms, ten (10) became hurricanes and one (1) strengthened to achieve major hurricane status – category three (3) or higher on the Saffir-Simpson Hurricane Wind Scale. The strongest tropical cyclone for the season, in terms of pressure was Hurricane Sandy with peak winds of 110 mph and minimum pressure of 940 mb; however, category 3, Major Hurricane Michael had the highest sustained winds of 115 mph and minimum pressure of 964 mb. Relative to Antigua and Barbuda, Isaac and Rafael brushed Antigua and Barbuda as tropical storms.

A number of records were or nearly broken during the 2012 hurricane season. The season had a hectic start and by June 23 Debby formed and become the earliest 4th named storm on record. Prior to the official start of the hurricane season, June 1, there were two preseason storms – Alberto and Chris – the second time on record two storms form in May in a given year, May 1887 was the only other time. It was also the first time since 1908 two named storms preceded the hurricane season and the third time on record. The most intense hurricane, in terms of lowest central pressure, was Hurricane Sandy; it is also considered the largest known Atlantic hurricane by gale diameter on record. Hurricane Nadine was the fifth longest-lived tropical cyclone on record. In addition, August 2012 was tied with August 2004, September 2002, and September 2010 for most number of named storms in a particular month, at eight.

It Only Takes One

Regardless of the numbers, we should always approach the hurricane season in the same manner each year: be aware and be prepared. The prevention of the loss of life and property from tropical cyclones is a responsibility that should be shared by all. As a reminder, recall our lesson from Hurricane George of 1998: it only takes one hurricane to make it a bad season. Accordingly, the Meteorological Service will play its usual role in alerting the public of any tropical cyclone that may form and threaten Antigua and Barbuda, the Leeward Islands and the British Virgin Islands. We endeavour to provide weather and climate information for the protect life, property, livelihood and the enhancement of the economy. Although the hurricane season officially runs from June 1 through November 30 each year, tropical cyclones can and have occurred outside the season – be prepared!

AnuStorms

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References

Accuweather.com, State College, Atlantic Hurricane Season: Three US Landfalls Predicted [online].
Available from: <http://www.accuweather.com/en/weather-news/atlantic-hurricane-forecast-2013/12116274>
[Accessed 3 June, 2013]

Colorado State University, Fort Collins, Extended Range of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2013 [online]. Available from: <http://typhoon.atmos.colostate.edu/Forecasts/2013/june2013/jun2013.pdf> [Accessed 3 June, 2013]

Florida State University, Raleigh, FSU COAP Atlantic Hurricane Season Forecast [online]. Available from:
<http://coaps.fsu.edu/hurricanes> [Accessed 3 June, 2013]

National Oceanic and Atmospheric Administration, Silver Spring, NOAA Predicts Active 2013 Atlantic Hurricane Season [online]. Available from: <http://www.noaanews.noaa.gov/stories2013/20130523_hurricaneoutlook_atlantic.html> [Accessed 28 May, 2013]

North Carolina State University, Raleigh, 2013 Atlantic Tropical Cyclone Outlook [online]. Available from: <http://cfdl.meas.ncsu.edu/research/TCoutlook_2013.html>%5BAccessed 28 May, 2013]

Tropical Storm Risk, London, Pre-Season Forecast for Atlantic Hurricane Activity in 2013 [online]. Available from: <http://www.tropicalstormrisk.com/docs/TSRATLPreSeason2013.pdf>[Accessed 28 May, 2013]

United Kingdom Met Office, Exeter, Seasonal Forecasting of Storms [online]. Available from:
< http://www.metoffice.gov.uk/weather/tropicalcyclone/seasonal/forecasting-method > [Accessed 3 June, 2013]





The Heart of the Hurricane Season

28 08 2012

By Dale C. S. Destin

Every year, persons across the Caribbean, Central America and the US Gulf and Atlantic Coasts pray for this period to pass quickly with out a hit – the heart of the hurricane season, which covers the period August to October (ASO). For the period 1851 to 2011, Antigua has had 93 named storms and 44 hurricane giving and average per year of 0.6 named storm and 0.2 hurricane for ASO. For Antigua, the heart of the hurricane season is August to September, which accounts for 79% (Aug 34%, Sep 45%) of all storms to affect the island. (http://www.antiguamet.com/Climate/climate_anu_cyclonesbyday.html ). This period has had 83 named storms and 41 hurricane for an average per year of 0.5 hurricane and 0.2 hurricane i.e. one storm every other year and one hurricane every five years.

August 21 and September 3 are very peculiar days for Antigua. These are the two peak days for Antigua for the hurricane season with a record of 7 named storms each to have affected the island on those days from 1851 to 2011. September 3 has produced three hurricanes and August 21 has produced four. (http://www.antiguamet.com/Climate/climate_anu_cyclonesbyday.html ) Two notorious tropical cyclones that have struck on August 21 were Category 3 Unnamed Hurricane of 1871 and Category 3 Hurricane Baker of 1950.

On average, ASO has 8 named storms and 5 hurricanes per year. Historically the period has had 1237 named storms of which 806 became hurricanes – 1851 to 2011 – with August contributing 362 named storms and 230 hurricanes; 80% of all storms (Aug  23%, Sep 37%, Oct 20%) form during the period ASO. This year has been no ordinary year contrary to initial forecasts; so far for August, there have been six named storms and three hurricanes, when the month averages two named storms and one hurricane. The record for named storms for August is eight, observed in 2004. The forecast for the overall season has moved from near – below normal to above normal/active season with a consensus of 14 named storms, 6 hurricanes and 3 becoming major hurricanes; already there has been 10 named storms  and 4 hurricanes. (http://www.antiguamet.com/Climate/HURRICANE_SEASON_FORECAST/2012AtlanticHurricaneSeasonForecastAug28.pdf) looks like we will actually see more than 14 when the season ends November 30. Currently, ENSO Positive conditions (El Nino) is trying to squelch of shut down the hurricane season as is the norm; however, the tropical North Atlantic is warming and other factors such as negative North Atlantic Oscillation (NOA) and Arctic Oscillation are in favour of further warming. Of course, there are other factors to consider but these are some of the main drivers of the hurricane season. What do you think will happen? How many more named storms will we see before the season ends?








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