The
2017 Atlantic hurricane season was an event in the annual
tropical cyclone season in the north
Atlantic Ocean. This
Atlantic hurricane season saw above-normal activity;[nb 1] it was the seventh most active season on record and the most active since
2005.[2] The season officially began on June 1, 2017 and ended on November 30, 2017. These dates, adopted by convention, historically describe the period in each year when most
tropical systems form.[3] However, storm formation is possible at any time of the year, as demonstrated in 2017 by the formation of the season's first
named storm, Tropical Storm Arlene, on April 19. The final storm of the season, Tropical Storm Rina degenerated to a remnant
area of low pressure on November 9.
The 2017 season produced 17 named storms, of which 10 became hurricanes including six of which intensified into
major hurricanes (Category 3, 4 or 5). Of those six,
Harvey and
Irma, became the first major hurricanes to make
landfall on the
continental United States in 12 years;[2] a third hurricane,
Nate, did so as well. September was both the most active month in the season and the most active month for Atlantic hurricanes ever recorded. Four long-lived major hurricanes—Irma,
Jose, Lee and
Maria—moved through the Atlantic Basin, as did the short-lived
Hurricane Katia. Overall, more
accumulated cyclone energy was generated during September 2017 than during the entire
2016 season.[4] In April 2018, the
World Meteorological Organization retired the names Harvey, Irma, Maria, and Nate from its rotating naming lists due to the number of deaths and amount of damage they caused, and they will not be used again for another Atlantic hurricane.[5]
This timeline documents tropical cyclone formations, strengthening, weakening, landfalls,
extratropical transitions, and dissipations during the season. It includes information that was not released throughout the season, meaning that data from post-storm reviews by the
National Hurricane Center, such as a storm that was not initially warned upon, has been included.
By convention, meteorologists use one
time zone when issuing forecasts and making observations:
Coordinated Universal Time (UTC), and also use the
24-hour clock (where 00:00 = midnight UTC).[6] The National Hurricane Center uses both UTC and the time zone where the center of the tropical cyclone is currently located. The time zones utilized (east to west) prior to 2020 were:
Atlantic,
Eastern, and
Central.[7] In this timeline, all information is listed by UTC first with the respective regional time included in parentheses. Additionally, figures for
maximum sustained winds and position estimates are rounded to the nearest 5 units (
knots,
miles, or
kilometers), following the convention used in the
National Hurricane Center's products. Direct wind observations are rounded to the nearest whole number. Atmospheric pressures are listed to the nearest
millibar and nearest hundredth of an
inch of mercury.
18:00 UTC (2:00 p.m. AST) at 16°48′N44°24′W / 16.8°N 44.4°W / 16.8; -44.4 – Tropical Depression Lee re-intensifies into a tropical storm about 1,105 mi (1,780 km) east of the northern Leeward Islands.[33]
06:00 UTC (2:00 a.m. AST) at 43°36′N48°00′W / 43.6°N 48.0°W / 43.6; -48.0 – Tropical Storm Rina becomes a post-tropical cyclone about 345 mi (555 km) southeast of Cape Race, Newfoundland, and later merges with a complex extratropical low pressure area.[nb 13][41]
November 30
The 2017 Atlantic hurricane season officially ends.[3]
^The National Hurricane Center initiated advisories on this system at 21:00 UTC (5:00 p.m. AST) on June 18, designating it Potential Tropical Cyclone Two.[9]
^The National Hurricane Center initiated advisories on this system at 21:00 UTC (4:00 p.m. CDT) on June 19, designating it Potential Tropical Cyclone Three.[12]
^The National Hurricane Center initiated advisories on this system at 21:00 UTC (5:00 p.m. EDT) on August 6, designating it Potential Tropical Cyclone Seven.[18]
^The remnants of Franklin moved westward across Mexico and into the Eastern Pacific Ocean, where they contributed to the formation of
Tropical Storm Jova on August 11.[20]
^The National Hurricane Center initiated advisories on this system at 15:00 UTC (11:00 a.m. AST) on August 17, designating it Potential Tropical Cyclone Nine.[23]
^The remnants of Katia moved westward across Mexico and into the Eastern Pacific Ocean, where they contributed to the formation of
Hurricane Otis on September 11.[32]
^The National Hurricane Center initiated advisories on this system at 15:00 UTC (11:00 a.m. AST) on September 16, designating it Potential Tropical Cyclone Fifteen.[34]
^The National Hurricane Center initiated advisories on this system at 21:00 UTC (5:00 p.m. EDT) on October 27, designating it Potential Tropical Cyclone Eighteen.[39]
^Operationally, Philippe was assessed as crossing the Florida Keys and exiting into the western Atlantic, but post-season analysis showed that this was a non-tropical area of low pressure that was interacting with Philippe.[40]
^This extratropical system, as
Cyclone Numa, moved across Europe and later acquired subtropical characteristics, becoming a rare "
medicane".[42]
^
abcdePasch, Richard J.; Latto, Andrew S.; Cangialosi, John P. (February 14, 2019).
Tropical Cyclone Report: Tropical Storm Emily(PDF) (Report). Miami, Florida: National Hurricane Center. Retrieved July 3, 2021.