The fast start to the 2017 Atlantic hurricane season continues. After nine days of being an invest, Invest 99L finally developed a well-defined circulation and sufficient organized convection to be designated a tropical depression Saturday evening. The National Hurricane Center (NHC) has initiated advisories on Tropical Depression Eight, located to the east-northeast of the Turks and Caicos Islands. Eight is likely to strengthen into a tropical storm and has the potential to strengthen to near hurricane strength along the Gulf Stream by the middle of next week. Eight is no threat to the United States. In the Eastern Pacific, Tropical Depression Jova is battling unfavorable conditions and is expected to degenerate into a remnant low tomorrow, and is no threat to land.

Tropical Depression Eight forms over the western Atlantic

An area of low pressure located a couple hundred miles to the east-northeast of the Turks and Caicos Islands has finally acquired a well-defined center, based on a recent scatterometer pass. Deep convection has also become better organized throughout the day. As of 11:00 p.m. EDT Saturday, Tropical Depression Eight was centered near 25.3°N 70.3°W, and was moving north-northwestward at about 13 mph. Maximum sustained winds were 30 knots (35 mph), with an estimated minimum pressure of 1011 mb.

The track forecast for Eight is straightforward, with the model guidance in tight agreement with a gradual turn out to sea without impacting any land areas other than high surf. Eight is expected to pass about halfway between the United States and Bermuda. The intensity forecast for Eight is difficult. Global models (such as the GFS and ECMWF) show the depression remaining very weak and perhaps dissipating in a couple days. The statistical guidance, as well as the HWRF model, are more bullish, and indicate the possibility that Eight could become a hurricane in about three days. Eight is expected to be in an environment with wind shear of less than 20 knots, sea surface temperatures above 28°C (84.2°F), and mid-level relative humidity values of about 50-55 percent. It is possible that dry air intrusions could limit development of thunderstorm activity. This environment should be favorable enough for at least gradual intensification, and I am siding more with the statistical guidance on the intensity forecast since global models often have issues with forecasting systems that have not yet developed into tropical cyclones.

Jova spinning down over the Eastern Pacific

The remnants of Hurricane Franklin acquired sufficient organization to be designated Tropical Storm Jova on Friday night. Since then, the cyclone has become less organized, and has since weakened to a tropical depression. As of 9:00 p.m. MDT (11:00 p.m. EDT), Tropical Depression Jova was centered near 20.6°N 114.7°W and was moving westward at about 15 mph. Maximum sustained winds were 30 knots (35 mph) with an estimated minimum pressure of 1005 mb. Jova is battling moderate wind shear of about 15 knots, with the convective mass to the southwest of the exposed low-level circulation. Jova is expected to degenerate into a remnant low tomorrow, and is no threat to land.

I will be back for another post tomorrow on TD Eight (which is likely to become Tropical Storm Gert by tomorrow) along with Jova and a few other areas to watch in the Atlantic and Pacific.