Fabio Peaks; TD 8W forms; Watching the Atlantic Next Week
The only named tropical cyclone on Earth this evening is Hurricane Fabio in the East Pacific. As of the National Hurricane Center's 5PM advisory, Fabio is currently located 660 miles SW of the tip of Baja California. It is moving WNW at 10mph. Fabio attained a peak intensity of 105mph yesterday and held that intensity through last night and most of today. Fabio has started to slowly weaken, however, and as of the 5PM advisory its maximum sustained winds have decreased to 100mph, with a minimum central pressure of 974mb.
Forecast for Fabio
Fabio is currently being steered by the subtropical ridge. A trough currently over the Northwest US will continue moving southeast and allow Fabio to turn further to the right. It should be moving due north by early Tuesday as the forecast track suggests.
Figure 1: Official NHC forecast track for Fabio
The intensity forecast is also fairly straightforward. Fabio is currently in an environment of fairly low shear and moderately dry air. It is steadily moving into cooler waters. Because shear is low and it is not in an extremely dry airmass, weakening should be gradual at first, for about the next 12-24 hours. After that, however, Fabio will move into much cooler waters and drier air as it turns north, so weakening should become more rapid by late tomorrow. If you were to extrapolate Fabio's projected path it would take it into northern Baja California, but Fabio should be dissipated well before it gets there. The NHC forecasts Fabio to become post-tropical by Wednesday evening, which I agree with.
Figure 2: Visible image of Hurricane Fabio. Its cloud filled eye indicates weakening. Image credit.
Also in the East Pacific, former Hurricane Emilia dissipated today and is now a weakening remnant low as it moves into the Central Pacific Hurricane Center's area of responsibility. Any redevelopment of Emilia is not expected as it is in very hostile conditions.
New Tropical Depression in the West Pacific
For the first time in a while, there is a tropical cyclone in the West Pacific Ocean tonight, Tropical Depression 8W. 8W is currently located about 630 nautical miles ESE of Kadena Air Base, Okinawa, according to the latest advisory from the Joint Typhoon Warning Center. It is moving WNW at about 14 knots. 8W is in a moderate shear environment. There is a lot of dry air to its northeast but more moist air to the west, the direction it is moving. It is also over warm waters right now. The intensity forecast is tricky because besides some shear, 8W will be moving into a favorable environment. However, right now it looks very poor as Figure 3 shows.
Figure 3: Tropical Depression 8W. Image credit.
8W has been unable to organize a good cloud and outflow pattern, likely because of the dry air to its northeast. The tricky part of the forecast is determining whether or not it will shake off this dry air, wrap convection around itself, and strengthen. The official JTWC forecasts brings 8W to a peak of 40 knots, which is likely a compromise between two possible scenarios.
1. 8W shakes off the dry air quickly and uses the more moist air in its path and warm waters to become a strong tropical storm.
2. 8W fails to organize due to shear and dry air and dissipates quickly or remains a weak tropical depression.
I think the second scenario is the more likely of the two, but just to be safe I will forecast a peak of 40mph, making it a minimal tropical storm.
The track forecast is easier. 8W is being steered by the subtropical ridge, and should continue tracking northwest for most of its lifespan. As it starts to arrive in cooler waters and weaken, it will begin to turn north. As the official track shows, this should result in 8W making landfall in South Korea as a weakening or dissipating system.
Figure 4: Official JTWC track for 8W.
Watching the Atlantic Next Week
Multiple models, including the GFS, are forecasting the potential for trough split development off the East Coast in about a week. Shear is lower than normal off the East Coast, so anything that attempts to form will have some chance. I give this potential East Coast development about a 30-40% chance of happening, a bit higher than I was thinking last night. Also in the Atlantic, a train of tropical waves continues to roll off of Africa. Conditions in the Central and Eastern Atlantic are not currently conducive for development however, so none of the waves will develop.
Thank you for reading, and have a great week!