The 2017 Atlantic Hurricane Season Summary

1 12 2017

Dale C. S. Destin|

The 2017 Atlantic hurricane season came to an end yesterday but will long be remembered for the costliest and one of the most destructive on record. It was also one of the most active hurricane seasons on record, breaking or equalling several records.

Hurricanes Katia (left), Irma (middle) and Jose (right)

Hurricanes Katia (left), Irma (middle) and Jose (right)

The hyperactive season produced 17 named storms, 10 hurricanes, 6 major hurricanes and 223 Accumulated Cyclone Energy (ACE). Overall, it is the seventh most active season on record (based on ACE) dating back to 1851 and the most active since 2005.

AtlanticHUrricaneSeasonSummary

Relative to the normal season of 12 named storms, 6 hurricanes, 3 major hurricanes and 106 ACE, this season had 42% more named storms than normal, 67% more hurricanes than usual, twice the normal number of major hurricanes and over twice the normal amount of ACE.

2017HurricaneSeasonSummaryGraphic

The furious 2017 Atlantic hurricane season left in its wake cataclysmic damage and is now the costliest hurricane season on record with cost amounting to over US$367 billion. The Caribbean contribution to this total is about US$120 billion.

Relative to Antigua and Barbuda

It was the most active hurricane season for Antigua and Barbuda, based on the number and strength of hurricanes passing within 105 nm of the islands. This season marks the first time on record that three major hurricanes passed in such proximity of the country. There have been other times with three or more tropical cyclones but none with three major hurricanes.

For the first three weeks of September, we had a ominous procession of major hurricanes – Irma, Jose and Maria. Irma was the strongest, in terms of sustained winds. The current hurricane scale goes from 1 to 5; however; if there were a 6, Irma would have been a Category 6 – it was super strong with peak sustained winds of 298 km/h (185 mph).

Super-Category 5 Hurricane Irma virtually wiped out Barbuda – damaging or destroying around 90% of buildings. Meanwhile, Antigua got away almost “scot-free” with only storm-force winds causing minimal damage.

Damaged and destroyed properties in Barbuda in the wake of Irma – Sep 6, 2017

Both Antigua and Barbuda dodge the bullets from Jose and Maria. Maria also produced storm-force winds; however, Jose passed without causing any notable winds. Notwithstanding, with Jose passing three days after Irma destroying Barbuda – the whole island had to be evacuated.

The expense to Antigua and Barbuda according to the National Office of Disaster Service (NODS): about US$140 million in damage; around US$20 million in losses and a recovery cost of about US$220 million. Most of the damage took place on Barbuda, where one person died during the passage of Irma.

On average, Antigua and Barbuda gets one named storm passing within 105 nm every other year, one hurricane every three years and a major hurricane every seven years. This is the first year on record we have been affected by Category 5 hurricanes – Irma and Maria.

AntiguaHurricaneSeasonSummary

Why was the season so active?

The season was hyperactive because of warmer than normal sea surface temperatures and very friendly atmospheric conditions – deep moisture levels and below normal vertical wind shear. This was especially so from around mid-August to early September.

The absence of an El Nino and conditions trending toward a La Nina also allowed for a more active season than normal.

Did climate change play a part?

There is no scientific evidence to support the notion that climate change had anything to do with the hyperactive 2017 Atlantic hurricane season or any previous hurricane season.

This is not to say that climate will not eventually have an impact on the hurricane season in the future. According to the Intergovernmental Panel on Climate Change (IPCC), climate change will, in the future, cause an overall decrease in the number of tropical cyclones but an increase in the number of major hurricanes.

Other notable records

Irma is the strongest hurricane on record to occur in the Atlantic Ocean – outside the Caribbean Sea and the Gulf of Mexico.

Maintaining peak intensity for 37 consecutive hours, Irma is the only tropical cyclone on record worldwide to have had winds that strong for so long.

Irma tied with 1935 US Labour Day hurricane for the strongest hurricane to ever make landfall in the Atlantic Basin.

September 2017 is the most active month on record for the Atlantic

Ten hurricanes in a row form during the 2017 Atlantic hurricane season – the most consecutive hurricanes on record.

Click here for more records.

Keep following for more on the just ended hurricane season, tropical cyclones and climate change and all things weather and climate. The next hurricane season starts June 1, 2018 – six months from now, let us all be prepared. Our first forecast for the next season will be issued around April 10.

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Tropical Cyclones and Climate Change

28 09 2017

Dale C. S. Destin |

With the current Atlantic hurricane season being hyperactive, thus far, and several countries being severely impacted by hurricanes, tropical cyclones (tropical depressions, tropical storms and hurricanes) continue to be made the “poster child” for the potential dangerous impacts of climate change.

Hurricane Irma - Sep 5-6, 2017. Travelling Across Barbuda and Anguilla.

Cat. 5 Hurricane Irma With Winds of 185 mph – Sep 5-6, 2017. The Eye travelled Across Barbuda and the Northern Leeward Islands.

This notion was crystallized by Former U.S. Vice President Al Gore on the cover of his book – “an inconvenient truth”, when he depicted a tropical cyclone (TC) spinning out of smoke stacks. Since then, several world leaders have supported this view, including former U.S. President Barak Obama, who said that “storms [are] growing stronger with each passing hurricane season”.

Over the years, many Caribbean leaders, have also joined in asserting that TCs have become stronger and more frequent due to manmade, greenhouse gas caused climate change. According to Prime Minister Gaston Browne of Antigua and Barbuda, “hurricanes are stronger and bigger because they are absorbing moisture from increasingly warmer seas, caused by global warming.” Browne’s colleague, Prime Minister Roosevelt Skerrit of Dominica supports this view and is convinced that Hurricane Maria is the product of climate change. He told the recent United Nations General Assembly that Maria was a climate change “truth we have just lived”.

Cat. 5 Hurricane Maria - 10:30, Sep 18, 2017- Eye Over Dominica.

Cat. 5 Hurricane Maria With Winds of 160 mph – 10:30 pm, Sep 18, 2017 – Eye Over Dominica.

There is no doubt that climate change is real and is happening. There is much evidence to point to. Contrary to the current U.S. President’s assertion, it is NOT a hoax created by the Chinese. However, do TCs deserve this poster-child position? How have TCs responded to manmade climate change? How will TCs respond to future climate change? Are there any doubts as to cause of Hurricanes Irma and Maria?

How have TCs responded, and how will they respond to human-induce climate change are topics of intense interest and public and scientific debates. Over the next few blogs, I will use the latest peer-reviewed scientific papers to answer these and related questions.

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A Hyperactive 2017 Atlantic Hurricane Season Thus Far

1 09 2017

Dale C. S. Destin |

We are at the halfway mark of the 2017 Atlantic hurricane season and it has been a hyperactive one with respect to named storms. On average, the first half of the season produces four named storms; however, this year it produced nine – more than doubled the amount. The last time there were 9 named storms by the end of August was 2012. Also this has only happened 5 times in the last 82 years.

2017HurricaneNames_Sep2017

Ensemble forecast

Most of the forecasts for the season are on track. The ensemble (mean) forecast, based on predictions from yours truly, the Integrated Forecast System of the ECMWF, the National Oceanic and Atmospheric Administration (NOAA), Klotzbach of Colorado State University and Saunders and Lea of Tropical Storm Risk.com (TSR) is for 17 named storms, 7 becoming hurricanes and 4 becoming major hurricanes.

Hurricane Season Forecast 2017

A better indicator of the activity for the season is the accumulated cyclone energy (ACE) index which is a measurement of the strength and duration of each tropical cyclone. Summing together the ACE of each cyclone, provides a more complete picture of how active the season is or likely to be outside of just the number of storms.

Thus far, the ACE is 29. This is relatively low and is indicative of the weak and short-live nature of the storms so far. The forecast is for a further 108 ACE over second half of the season. For the whole season, the ensemble forecast calls for an ACE index of 136. If this forecast pans out, the 2017 season would be around 30% more active than normal and the highest in seven years.

Tropical North Atlantic

The tropical North Atlantic is almost catching fire. It is the warmest June to August since 2010 and the third warmest on record dating back to 1948. The very warm sea surface temperatures are the main reason for the more than doubling of the number of named storms normal for up to this time of the year.

Probability of Antigua being hit by a hurricane

According to Klotzbach, the likely best similar years to the upcoming 2017 AHS are 1953, 1969, 1979, 2001 and 2004. Over these year, we were affected by four named storms with one being a major hurricane. Thus, based ONLY on similar years, the probability of Antigua being affected by one or more named storms is around 54%, up 5% fro the average. However, the probability for one or more hurricanes is around 2%, down by 20% from the average. Notwithstanding, as I write, there is Category 3 Hurricane Irma tracking towards the island, causing a great scare.

We are in the peak of the hurricane season – keep monitoring and complete your hurricane plan, just in case you need to use it.

Follow us and stay updated on the 2017 AHS via our social media platform, which includes twitter, facebook, wordpress, instagram, tumblr, and google+. Follow us also for all things weather and climate.








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