The first tropical depression of the 2018 Pacific hurricane season, Tropical Depression One-E, is holding on as a tropical depression despite strong wind shear over the eastern Pacific. One-E, which formed on Thursday afternoon, is likely to degenerate into a remnant low late today or early tomorrow. The remnants of One-E should move slowly north-northwestward before fully dissipating by Sunday. One-E is no threat to any land areas.

As of 8:00 a.m. PDT (11:00 a.m. EDT), Tropical Depression One-E was centered near 12.7°N 129.0°W, and was moving westward at about 5 mph. Maximum sustained winds were 30 knots (35 mph), with an estimated minimum pressure of 1006 mb. Strong westerly wind shear of over 40 knots has exposed the well-defined circulation to the west of the convection mass. The strong shear is expected to continue for the next several days. In addition, One-E will be moving over cooler waters, and into a drier and more stable environment. As a result, no strengthening is anticipated, and it appears highly unlikely that One-E will strengthen into Tropical Storm Aletta.

It is interesting to note that the location of One-E is unusually far west for a tropical cyclone before July in the eastern Pacific basin.

Gulf of Mexico worth watching early next week

We may have to keep an eye on the Northeastern Gulf of Mexico early next week for possible weak subtropical or tropical cyclogenesis. An upper-level low is expected to develop west of the Florida peninsula by Sunday, before likely drifting northward to north-northwestward over the Northeastern Gulf of Mexico. The 00z Friday GFS, UKMET and ECMWF models do not predict a subtropical or tropical cyclone will form; however, this system has modest support from the GEFS and EPS ensembles for possible weak development. Environmental conditions are only expected to be marginal for development: wind shear is likely to be moderate and sea surface temperatures are a cool 25°C (77°F). As a result, if something does develop, it is likely to be subtropical rather than tropical. The first name on the Atlantic naming list is Alberto. I will continue to monitor this system and the models during the next few days. The Atlantic hurricane season does not officially begin until June 1.

Do not take long-range GFS forecasts of Caribbean genesis seriously

The GFS model has been persistently showing a strong tropical cyclone develop over the Southwestern Caribbean Sea in the 8-10 day time frame, before moving up northward into the Gulf of Mexico. It is highly likely that what the GFS is showing is a classic “ghost storm.” The GFS model has been known to have a bias in developing pre-season Caribbean tropical cyclones that almost never come to fruition. While it is likely this region will have enhanced convection, it is not likely a tropical cyclone will develop. The ECMWF and UKMET models show lowering pressures in the area, but no tropical cyclone development. The system the GFS develops is moving back in time, a key warning sign that what the GFS is showing is most likely a suspect genesis event driven by convective feedback.

I will be back with another post tomorrow.