The tropics are very active today. In the Central Pacific, Hurricane Hector is currently a Category 4 hurricane, slightly weaker than yesterday when it neared Category 5 intensity. Hector is expected to pass south of the Hawaiian Islands, but a Tropical Storm Watch is currently in effect for Hawaii’s Big Island. In the far eastern Pacific, Hurricane John is gradually strengthening and is now a Category 2 hurricane. To the west of John is newly formed Tropical Storm Kristy, which poses no threat to land. In the Atlantic, Invest 97L has developed into Subtropical Storm Debby, the fourth named storm of the 2018 Atlantic hurricane season.

As of 11:00 a.m. HST (5:00 p.m. EDT) Tuesday, Hurricane Hector was centered near 16.4°N 149.1°W, and was moving westward at about 16 mph. Maximum sustained winds were 115 knots (130 mph), with an estimated minimum pressure of 950 mb. Hector is slightly weaker than yesterday, when it was very near Category 5 intensity. The weakening likely occurred as a result of Hector moving over slightly cooler waters, limiting its maximum potential intensity. Hector is likely to remain a powerful hurricane for the next several days as it moves westward to west-northwestward, though fluctuations in intensity are likely. The center of Hector is expected to pass about 150-200 miles south of the Big Island of Hawaii tomorrow, and the storm will likely be too small to cause significant effects to the Hawaiian islands. However, a Tropical Storm Watch is currently in effect for the Big Island, and tropical storm force winds cannot be ruled out. In about 6-7 days, Hector is likely to cross the International Date Line and be reclassified as a West Pacific typhoon.

As of 3:00 p.m. MDT (5:00 p.m. EDT) Tuesday, Hurricane John was centered near 18.7°N 110.5°W, and was moving northwestward at about 10 mph. Maximum sustained winds were 90 knots (105 mph), with an estimated minimum pressure of 969 mb. The center of John is currently located near the sparsely populated Socorro Island. John currently has an open eyewall structure, and this will likely prevent any significant intensification from this point forward. John still could attain major hurricane strength, though. John is likely to begin weakening by tomorrow night as it moves over cooler waters and should become a remnant low by Saturday.

As of 2:00 p.m. PDT (5:00 p.m. EDT), Tropical Storm Kristy was centered near 13.7°N 127.1°W, and was moving westward at about 13 mph. Maximum sustained winds were 45 knots (50 mph), with an estimated minimum pressure of 1000 mb. Kristy is currently located in a somewhat conducive environment for intensification, and could become a hurricane on Thursday before weakening begins by Friday.

As of 5:00 p.m. AST Tuesday, Subtropical Storm Debby was centered near 39.7°N 49.2°W, and was moving north at about 15 mph. Maximum sustained winds were 35 knots (40 mph), with an estimated minimum pressure of 1008 mb. Debby has a classic appearance of a subtropical cyclone with a band of moderate convection north of a mostly cloud-free center. Debby is the fourth named storm of the 2018 Atlantic hurricane season, which on average does not form until August 23. Debby is not likely to strengthen much, if at all, since it is expected to move over waters cooler than 26°C (78.8°F) early Wednesday morning. Debby is likely to lose subtropical characteristics by tomorrow night or Thursday morning as it becomes devoid of deep convection. Debby is no threat to land.