Tropical Storm Eugene is very close to becoming the second hurricane of the 2017 Pacific hurricane season. In the Atlantic, the remnants of Tropical Depression Four have a low chance of regenerating into a tropical cyclone, and a tropical wave exiting the coast of Africa will need to be watched for development late next week when it is expected to be near the Lesser Antilles.

Eugene expected to be upgraded to a hurricane, could peak at category 2 status

Tropical Storm Eugene has rapidly strengthened today in very favorable conditions, and is very close to hurricane strength. In fact, the 00:00 UTC ATCF intensity of Eugene was 65 knots (75 mph), which likely means that Eugene will be upgraded to a hurricane at 8:00 p.m. PDT (11:00 p.m. EDT). Eugene is a large storm, with a banding eye feature.

As of 2:00 p.m. PDT (5:00 p.m. EDT), Eugene was centered near 13.7°N 113.4°W, and was moving northwest at 8 mph.  Maximum sustained winds were 60 knots (70 mph) with an estimated minimum pressure of 995 mb.  Eugene is likely to continue on a northwestward motion for the next several days, and. Wind shear will remain light (less than 5 knots) throughout the forecast period, but sea surface temperatures are beginning to decrease and are expected to drop below 26°C (78.8°F) in about 24-36 hours. Some intensification with Eugene is likely through tomorrow evening, and Eugene could be a category 2 hurricane before water temperatures become too cold for strengthening. The official National Hurricane Center (NHC) forecast brings Eugene to 90 mph at peak in about 24 hours. Eugene is not expected to pose a threat to land, and should degenerate into a remnant low by the middle of next week.

Keep an eye on the remnants of Tropical Depression Four

The remnants of Tropical Depression Four remain intact this evening, and deep convection has been bursting north of the center. This convection is likely being aided by the presence of an upper-level low nearby. The remnants of Four are currently in an environment with moderate wind shear of about 20-25 knots (25-30 mph) but wind shear could drop to less than 10 knots (10 mph) by Monday as it nears the Bahamas. While the global models do not currently forecast regeneration, the conditions will be marginally favorable for some slight re-development when the system is likely to be near the Florida coast. The NHC has not mentioned the remnants of Four in their Tropical Weather Outlook.

African tropical wave still could develop near Lesser Antilles

An African tropical wave is currently exiting the coast of western Africa, and is likely to move quickly westward over the tropical Atlantic for the next several days. By the end of next week, the tropical wave could be near the Windward Islands, and the GFS and CMC models have indicated the possibility for tropical development to occur here. The 12z Saturday GFS and CMC model runs predicted that this tropical wave would develop into a tropical storm in the southeastern Caribbean Sea. The GFS model has backed off the idea of a strong hurricane like it had been suggesting in prior runs. The 12z Saturday ECMWF run did not predict development of this wave. Travelling at a low latitude, the wave should be able to avoid the strongest Saharan Air Layer (SAL), but at a low latitude it is difficult for a tropical wave to take advantage of the Earth’s spin and develop into a tropical cyclone. In addition, the wave may not gain enough latitude, and could even interact with South America without development. I give this tropical wave a 30 percent chance of development during the next ten days. The NHC has not yet mentioned this tropical wave in its Tropical Weather Outlook.

I will be back tomorrow for an update on these three systems.