<Tr> <Th> Duration </Th> <Td> September 23--October 13 </Td> </Tr> <Tr> <Th> Peak intensity </Th> <Td> 90 mph (150 km / h) (1 - min) 969 mbar (hPa) </Td> </Tr> <P> In the midst of an active September, the NHC began monitoring an area southwest of the Azores for tropical or subtropical development within the next several days on September 19 . A non-tropical area of low pressure formed on September 22, quickly transitioning into a subtropical storm by 15: 00 UTC on the next day, with the NHC assigning the storm the name Leslie . After little change in strength had occurred in two days, Leslie began to weaken, first into a subtropical depression early on September 25, before becoming post-tropical later that day as the system began to merge with an approaching frontal system . Leslie subsequently merged with the frontal system and began a cyclonic loop to the west, intensifying during this time, and becoming a powerful extratropical cyclone with hurricane - force winds early on September 27 . </P> <P> After reaching its extratropical peak, Post-Tropical Cyclone Leslie gradually weakened, as the storm began to lose its frontal structure . However, Leslie simultaneously began to reacquire subtropical characteristics, and by 21: 00 UTC on September 28, Leslie became a subtropical storm once again . A day after regenerating, Leslie became fully tropical . Over the next several days, Leslie slowly drifted to the south - southwest, while gradually intensifying . At 09: 00 UTC on October 3, Leslie strengthened into a Category 1 hurricane, the sixth hurricane of the season . However, Leslie weakened back into a tropical storm late on the next day, with satellite data indicating that Leslie may have been trying to undergo an eyewall replacement cycle, albeit with a very large eye . For the next few days, Leslie slowly continued to drift northeastward, without much change in intensity . On October 7, Leslie began turning to the east - southeast . After a period of weakening, Leslie started restrengthening late on October 8 . Early on October 10, Leslie intensified into a Category 1 hurricane for the second time and executed a sharp turn to the east - northeast . At 18: 00 UTC on October 13, Leslie transitioned into a powerful extratropical cyclone 120 miles west - northwest of Lisbon, before making landfall soon afterward . </P>

When did tropical storm leslie form in 2018
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