Invest 96E over the eastern Pacific has developed into Tropical Storm Emilia – the fifth named storm of the 2018 Pacific hurricane season, all of which have formed in June. The average fifth named storm in the eastern Pacific basin does not form, on average, until July 22. While Emilia is not likely to become a hurricane, a tropical wave to the east (designated Invest 97E) is likely to become a stronger storm than Emilia (though the intensity guidance has backed off today). The Atlantic basin remains very quiet with no active cyclones nor new cyclones expected to develop over the next five days.

As of 9:00 a.m. MDT (11:00 a.m. EDT) Thursday, Tropical Storm Emilia was centered near 14.4°N 112.4°W, and was moving west-northwestward at about 14 mph. Maximum sustained winds were 35 knots (40 mph), with an estimated minimum pressure of 1005 mb. Although moderate easterly shear is affecting the cyclone, the shear should decrease to below 10 kt in about 36-48 hours. However, at the same time, Emilia will be moving into cooler waters and into a drier, more stable air mass. As a result, Emilia is not likely to reach hurricane strength and will most likely peak as a high-end tropical storm. Interestingly, the GFS and HWRF models bring Emilia to minimal hurricane strength, though most other intensity models predict only modest strengthening. Emilia is no threat to land, and should degenerate into a post-tropical remnant low by Monday, if not sooner.

To the east of Emilia, there are two more tropical waves that may develop into new tropical cyclones during the next five days or so. The first, Invest 97E, is expected to develop by the end of the weekend. As of 12:00 UTC Thursday, Invest 97E was located near 9.7°N 95.8°W, and was moving generally west-northwestward. Maximum sustained winds were 20 knots (25 mph), with an estimated minimum pressure of 1009 mb. 97E is gradually becoming better organized, and a broad area of low pressure has formed. Like Emilia, 97E poses no threat to land. Global models are in very good agreement that 97E will develop into a tropical cyclone, though they have backed off significantly in intensity. 97E is expected to remain over warm water above 28°C (82.4°F) for the next five days, with wind shear gradually decreasing to below 10 knots by the end of the forecast period. The National Hurricane Center (NHC) gives 97E a 60 percent chance of development within 48 hours, and a 90 percent chance within five days.

To the east of 97E, another tropical wave is expected to move into the eastern Pacific from the southwestern Caribbean on Saturday. Conditions are likely to be conducive for development, and the NHC gives a near zero percent chance of development within 48 hours but a 30 percent chance within five days. Like Emilia and 97E, this system will most likely not pose a threat to land if development occurs.

The next two names on the eastern Pacific naming list are Fabio and Glima. I will be back with another post on the tropics by Saturday.