Hurricanes Erick and Flossie over the eastern Pacific have both weakened since yesterday, with Flossie weakening to a tropical storm due to strong westerly shear. Erick should remain south of the Hawaiian Islands as it gradually weakens. Flossie could pass close to the islands in about 6 days or so, but marginal sea surface temperatures and increasing wind shear should weaken Flossie as it approaches from the east.

In the Atlantic, a tropical wave has a strong chance to develop into a tropical depression by early next week as it approaches the Lesser Antilles. Development is not likely for the next few days, though, but environmental conditions are likely to become more conducive by late this weekend.

Erick and Flossie weakening

As of 11:00 a.m. HST (5:00 p.m. EDT) Wednesday, Hurricane Erick was centered near 14.8°N 148.8°W, and was moving west-northwestward at 14 mph. Maximum sustained winds were 100 knots (115 knots), with an estimated minimum pressure of 960 mb. Although Erick is still a major hurricane, it has become less organized since yesterday, with a distinct eye no longer visible in satellite imagery. Although the vertical shear is currently not very high and sea surface temperatures are expected to remain above 27°C (80.6°F) for the next five days, shear is expected to increase to above 30 knots in about 24 hours and remain strong for the rest of the forecast period. Erick should weaken to a tropical storm in a day or two, and should gradually weaken over the coming days. Erick will likely become a remnant low in five days or so.

As of 11:00 a.m. HST (5:00 p.m. EDT) Wednesday, Tropical Storm Flossie was centered near 14.0°N 127.3°W, and was moving westward at about 16 mph. Maximum sustained winds were 60 knots (70 mph), with an estimated minimum pressure of 995 mb. A recent ASCAT pass suggests this intensity could be a little generous, and it is quite possible Flossie never even reached hurricane strength yesterday. Flossie’s low-level circulation has become exposed to the west of the main convective mass, indicative of strong westerly wind shear affecting the cyclone. This shear is likely to continue for the next 24 hours at least, so some additional weakening appears likely in the short term. However, wind shear could decrease in about 48 hours or so briefly, so Flossie could strengthen to a hurricane, but Flossie will be moving over cooler waters by that time. As Flossie approaches the Hawaiian Islands, another increase in wind shear is likely, so it is highly unlikely Flossie will make landfall in the state at hurricane intensity.

Tropical wave over the eastern Atlantic could develop as it approaches the Leeward Islands

A tropical wave is producing a broad area of shower and thunderstorm activity over the eastern tropical Atlantic Ocean. It could lead to the formation of the first tropical cyclone in the Atlantic’s Main Development Region (MDR) of 2019. Due to unfavorable environmental conditions and the broad nature of the disturbance, little development appears likely during the next three days or so. However, this wave could gradually organize into a tropical depression by Sunday or Monday as it approaches the Leeward Islands. The 12z ECMWF, GFS, UKMET and CMC models all developed this tropical wave into a tropical cyclone by next Tuesday. The GFS model has become the most aggressive, predicting this wave would become a hurricane over the western Atlantic by late next week. The other models are weaker, showing this system remaining weak and sheared. The National Hurricane Center (NHC) gives this wave a near zero percent chance of development within 48 hours, but a 60 percent chance within five days. The next name on the Atlantic naming list is Chantal.