The Atlantic Hurricane Season Consensus Forecast – Aug 14, 2013

14 08 2013

| Dale C. S. Destin

The general consensus among tropical cyclone experts continues to be for an above normal Atlantic Hurricane Season for 2013. The consensus forecast calls for 17 named storms, 8 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).  Much of 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.

Hurricane Season Outlook

What 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 32% chance or 3 in 10 chances of one or more hurricanes affecting Antigua (directly or indirectly) over the period August – October; this is 4% above the long term chance (1981 – 2010).

The 2013 Hurricane Season

The 2013 Atlantic Hurricane Season, thus far, have produced four (4) named storms. The strongest tropical cyclone for the season has been Tropical Storm Andrea with peak winds of 65 mph and minimum pressure of 992 mb. There has been no hurricane, thus far. Relative to Antigua and Barbuda, Chantal, during it passage through the Eastern Caribbean, spawned a destructive water spout, which impacted Camp Blizzard, Antigua. The hurricane season officially runs from June 1 through November 30 each year; however, tropical cyclones can and have occurred outside the season. The peak of the hurricane season is mid August to late October while the peak of the hurricane season for Antigua is mid August to late September (graph 1).

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 – be prepared!

AnuStorms

Graph 1: Antiguan Tropical Cyclones – distribution of tropical cyclones within 120 statute miles of Antiguan (1851 – 2012)

For more information see the links below or email me at dale_destin@yahoo.com. You are also welcome to follow us via twitter facebook youtube and blog .

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References

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

Colorado State University, Fort Collins, Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2013 [online].
<http://typhoon.atmos.colostate.edu/Forecasts/2013/aug2013/aug2013.pdf>
[Accessed 12 August, 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: Atlantic hurricane season on track to be above-normal [online]. Available from: <http://www.noaanews.noaa.gov/stories2013/20130808_atlantichurricaneupdate.html>
[Accessed 12 Aug, 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, August Forecast Update for Atlantic and U.S. Hurricane Activity in 2013 [online]. Available from: <http://www.tropicalstormrisk.com/docs/TSRATLForecastAug2013.pdf>
[Accessed 12 Aug, 2013]

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

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Antiguan Storms During July

15 07 2013

Dale C. S. Destin |

What is Antigua’s record with respect to tropical cyclones in July? While tropical cyclones are unlikely to affected Antigua during the month of July, it is not unheard of. For the period 1851 to 2012, Antigua has been affected by six tropical storms, including one hurricane (AntiguanStorms). The last tropical cyclone to have affected Antigua in July was Hurricane Bertha in 1996. The system produced 39 mph sustained winds with gusts near 60 mph.  Total rainfall from it, measured at the airport was 49.1 mm. Based on the active multi-decadal period that we are in, which started around 1995, the probability of a storm or hurricane affecting Antigua is 5% (one every 20 years) as compared to the (1981 – 2010) normal of 3% (one every 33.3 years). Broadly speaking, we a not due another storm in July until sometime in the period 2016 – 2029. Meanwhile, a major hurricane has never affected the country during July.

Two tropical storms formed during the month of June in the North Atlantic Basin. Based on a 30-year (1981 – 2010) average, a tropical storm forms in June in the basin about once every other year.








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