User:HurricaneGonzalo/Hurricane Lee (2017)

Hurricane Lee was a long-lasting, unusual hurricane that traversed the Atlantic during September 2017. The 5th major hurricane of the hyperactive 2017 Atlantic hurricane season, Lee lasted 15 days as a tropical cyclone. Hurricane Lee originally was a weak tropical storm that dissipated over the Central Atlantic. After a few days, the National Hurricane Center (NHC) began monitoring the storm again, and invested the remnants of Lee. On September 22, the storm reorganized into a tropical depression and later became a hurricane. The storm reached its peak intensity on September 27, when Lee became the 5th major hurricane. Hurricane Lee continued the record-tying hurricane streak that occurred during the season, lasting from Franklin to Ophelia.

Meteorological history
Lee's origins can be traced to a tropical wave that emerged off of the coast of Africa on September 13, first with a 20% chance of formation within the next five days. At 06:00 (UTC) on September 14, the tropical wave's formation chances went up to 30% for the next five days. At 13:00 (UTC) on September 14, the chances of formation continued to increase, as it became 40% for the next five days. Gradual future development was noted in this outlook. Later that day, another tropical weather outlook was released and the tropical wave was invested. The storm was designated as Invest 97L as it continued to move westward near Cabo Verde. Chances of development at the same time were upped to 70% within the next five days. Invest 97L developed a closed circulation, and Dvorak classifications assigned an intensity of 2.0. It became Tropical Depression Fourteen on September 15. Tropical Depression Fourteen remained at nearly the same intensity for about a day due to the lack of ASCAT scans. The depression began to fluctuate in intensity on September 15, as the storm tried to organize. The circulation of the storm began to be exposed in the next advisory, as the storm continued to weaken. Little change in intensity was noted. Forecasts for Tropical Depression Fourteen began to become less supportive for conducive conditions for further development, and forecasters only expected the storm to peak at 40 kts, or 45 mph before weakening. However, despite unfavorable conditions, Tropical Depression Fourteen developed into a tropical storm and was given the name Lee. The intensification of this system was confirmed by a partial ASCAT pass, and Dvorak classifications assigned a number of 2.5. Tropical Storm Lee remained at a similar intensity, having winds of 35 kts, or 40 mph. Strong upper-level winds kept Tropical Storm Lee from further strengthening. Most of Lee's forecasting was done my computer models, which were predicting Lee to degenerate into a low by the 96 hour mark. Tropical Storm Lee entered vertical shear that exceeded 30 knots, or 35 mph. This caused Lee to drastically weaken into a tropical depression on September 17. As the tropical depression continued westward, the deep convection in the system dissipated around the same time as the system weakened. A burst of convection briefly appeared on the same day on Tropical Depression Lee. However, dry air and increasing shear kept the storm from further strengthening. On September 18, the aforementioned deep convection burst waned and had disappeared due to vertical shear. Vertical shear, which causes tropical cyclones to significantly weaken, increased to over 30 kts. Tropical Depression Lee continued to deteriorate due to increasing deep-layer shear. However, another burst of deep convection occurred east of the center of the tropical depression. This deep convection dissipated later that day, leaving only a low-level cloud swirl. Shear over the storm increased to 40 kts as it degenerated into a remnant low on September 19. The National Hurricane Center issued their final advisory for Tropical Storm Lee on September 19.

Late in the morning on September 19, the remnants of Lee appeared on the tropical weather outlook. Forecasters noted that conditions would be marginally conducive for redevelopment. Disorganized shower activity was noted by forecasters. Late on September 19, the tropical remnants of Lee were given a 60% chance of regeneration within the next five days. It was noted that showers and thunderstorms had been increasing near the center of the remnants. Chances for regeneration were upped to 70% within the next five days on September 20, noting that the system was producing gale-force winds. It was also noted that only a slight increase in development would cause the storm to regenerate. Chances remained at 70% later that morning, noting the same characteristics that were shown on satellite earlier in the morning. Chances significantly dropped to a 50% chance of regeneration. The presence of gale-force winds had disappeared as the system was invested, which caused the chances of regeneration to be significantly dropped. The chance of regeneration dropped even further to 30% later that evening. On September 21, the remnants of Lee left the tropical weather outlook. Forecasters noted that conditions had become too unfavorable for development. On September 22, the system surprisingly made a reappearance on the tropical weather outlook, and was invested. It was designated as Invest 98L. Later that day, the system reorganized into Tropical Depression Lee. The system regenerated due to a large convective burst near the center of the storm. Very early on September 23, Le restrengthened into a tropical storm. Forecasters began to become confused about the future track of Lee. Most forecasters were uncertain on which way the system would go, which is not that uncommon. Tropical Storm Lee remained at the same wind speed but was expected to intensify into a Category 1 hurricane. Tropical Storm Lee broke its previous peak intensity, with winds of 45 mph and a barometric pressure of 1007 mbar. Tropical Storm Lee continued to produce a small cluster of deep convection, drifting slowly to the northwest. In the next advisory, Lee strengthened into a tropical storm with sustained winds of 45 knots, or 50 mph. A WindSat overpass indicated that Lee had developed a coherent inner core. On top of that, it indicated that a ring of shallow moderate convection surrounded the inner core, similar to that of a rapidly intensifying tropical cyclone. This turned out to be true, and on September 24, Lee strengthened into a Category 1 hurricane with 75-mph winds. Satellite imagery indicated a developed eye in the center of the storm. Lee soon had sustained winds of 85 mph, solely based on application to an IR satellite imagery of the storm. Lee began to drift southward, as it slowed in its intensification rate. Forecaster Brown noted that cloud tops still continued to cool as the intensification rate slowed down. Brown also noted that Lee was very tricky to forecast due to its small size and the path of the system, which would cause upwelling, a cooling of the waters beneath the storm. This would cause the storm to weaken. At this time, Lee had ended its near-cyclonic loop as it traveled southeastward. Lee stalled in intensity on the evening of September 24, with storm-force winds only reaching out 30 nautical miles. Lee remained at this intensity through early September 25, when the storm began to pass through its own SST wake, causing Lee to halt its strengthening trend. Moderate vertical shear began to affect the system on September 25, causing Lee to slightly weaken as it moved south-southwest. However, this did not last long, and Lee began to strengthen again later that day. This was caused by the movement of Lee, moving its way out of the moderate vertical shear that was associated with an upper-level trough. Forecaster Zelinsky noted that the storm was likely to strengthen as it was moving away from any cold waters that the storm upwelled. On September 26, Hurricane Lee strengthened into a Category 2 hurricane, with winds of 100 mph, moving to the west. Strengthening continued to occur later that day, reaching a sustained wind speed of 110 mph before the day was over. Lee began to go through an eyewall replacement cycle, keeping Lee's intensity at 110 mph. However, this eyewall replacement cycle caused Lee to strengthen into the season's fifth major hurricane on September 27, with sustained winds of 115 mph. Hurricane Lee attained this peak intensity for another advisory, just as the storm began to move to the northwest. Hurricane Lee began to move into slightly more hostile conditions very late on September 27, as Lee weakened into a high-end Category 2 hurricane.