Atlantic Summary for October 2017
Monthly Summary

000 ABNT30 KNHC 011150 TWSAT Monthly Tropical Weather Summary NWS National Hurricane Center Miami FL 800 AM EDT Sun Oct 1 2017 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: The North Atlantic basin was extremely active in September. Four tropical cyclones formed, all of which became hurricanes, and three of those four became major hurricanes. Hurricane Irma was also present in the basin as a major hurricane during the month, although it formed in late August. Both Irma and Maria reached category 5 intensity during the month of September. Based on a 30-year climatology (1981-2010), the number of named storms forming in the basin during September was near average, but the numbers of hurricanes and major hurricanes were both well above average. In terms of the Accumulated Cyclone Energy (ACE), which measures the combined strength and duration of tropical storms and hurricanes, September 2017 was the most active month on record, easily breaking the previous record of September 2004. Overall, this September was about 3.5 times more active than an average September from 1981-2010. From a seasonal perspective, activity in the Atlantic basin so far in 2017 is well above average, and this season is the 3rd most active on record to date in the basin, behind 1933 and 2004. Reports on individual cyclones, when completed, are available at the National Hurricane Center website at www.hurricanes.gov/data/tcr/index.php?season=2017&basin=atl . Summary Table Name Dates Max Wind (mph) --------------------------------------------------- TS Arlene 19-21 Apr 50* TS Bret 19-20 Jun 45 TS Cindy 20-23 Jun 60 TD Four 6- 7 Jul 30 TS Don 17-18 Jul 50 TS Emily 31 Jul- 1 Aug 45 H Franklin 6-10 Aug 85 H Gert 13-17 Aug 105 MH Harvey 17 Aug- 1 Sep 130 MH Irma 30 Aug-12 Sep 185 MH Jose 5-22 Sep 155 H Katia 5- 9 Sep 105 MH Lee 15-30 Sep 115 MH Maria 16-30 Sep 175 --------------------------------------------------- * Denotes a storm for which the post-storm analysis is complete. $$ Hurricane Specialist Unit
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