Tropical Depression Three Discussion Number 3

Wiki-Hurricanes Forecast Center

11:00 PM EDT Fri Jul 6 2018

Three has not become better organized over the past few hours, and in fact, most associated deep convection has dissipated. This isn't completely surprising given the broad nature of the circulation, with tropical processes still underway. An 01:37z ASCAT pass showed that maximum winds east of the center remained near 25kt, and that is the intensity used for this advisory.

The system is located in a generally favorable environment for intensification. Wind shear is currently low, and although it is expected to increase in about 24 hours as the system interacts with an impinging cold front, this uptick is expected to be transient in nature. Water temperatures are on the order of 28-29°C, more than sufficient for intensification, and warm enough for rapid intensification if Three is able to develop a stable inner core. The surrounding environment is not full of moisture, but it is adequate. Most intensity guidance suggests steady intensification over the next 5 days, including SHIPS at 85kt and LGEM at 70kt. The situation is complicated by the fact that the HMON, ECMWF, and FV3 all show little intensification of the system. Given the favorable environment, the forecast continues to call for a hurricane-strength storm, with some potential caveats.

The system is currently located on the western edge of a subtropical ridge, dictating a north-northwest motion. Steering currents are expected to collapse by this time tomorrow, allowing Three to meander offshore the North Carolina coastline for several days before an approaching upper-level trough accelerates the storm northeast. Most guidance is in good agreement that such a track will occur, with the exception of the HWRF which sent the system into the Outer Banks. This appears to be an outlier for now, but there is still potential for a shift in track that could bring a tropical cyclone close to the East Coast of the United States by the middle of the week.


INIT 07/0300Z 25 KT 30 MPH

12H 07/1200Z 25 KT 30 MPH

24H 08/0000Z 30 KT 35 MPH

36H 08/1200Z 35 KT 40 MPH

48H 09/0000Z 45 KT 50 MPH

72H 10/0000Z 55 KT 65 MPH

96H 11/0000Z 65 KT 75 MPH

120H 12/0000Z 70 KT 80 MPH

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