Current Snapshot

The Pacific Disaster Center’s (PDC Global) Wednesday, August 14, 2024, Tropical Cyclone Activity Report…for the Pacific Ocean, the Indian Ocean, and adjacent Seas

Current Tropical Cyclones:

Tropical Cyclone 08W (Ampil)…is located approximately 165 NM north-northwest of Chichi Jima, Japan

Tropical Cyclone 09W (Wukong)…is located approximately 334 NM east of Yokosuka, Japan – Final Warning

Northeast Pacific Ocean: There are no Tropical Cyclones

>>> Offshore Southwestern Mexico:

An area of low pressure will likely form this weekend well offshore of southwestern Mexico. Some subsequent slow development is possible, and a tropical depression could form early next week as the low moves west-northwestward.

* Formation chance through 48 hours…low…near 0 percent
* Formation chance through 7 days…medium…40 percent

Central North Pacific: There are no Tropical Cyclones

>>> Well Southeast of the Hawaiian Islands:

A broad area of low pressure will likely form during the next couple of days well southeast of the Hawaiian Islands. Environmental conditions appear conducive for gradual development thereafter, and a tropical depression could form this weekend or early next week while the system moves westward. Information on this system can also be found in the Tropical Weather Outlook for the Central Pacific basin.

* Formation chance through 48 hours…low…20 percent
* Formation chance through 7 days…medium…60 percent

Western Pacific, Indian Ocean and adjacent Seas:

Tropical Cyclone 08W (Ampil)

According to the JTWC Warning number 11, sustained winds are 85 knots with gusts to near 105 knots

Animated multi-spectral satellite imagery depicts a compact core with spiral bands of deep convection present to the north, east and south of the system, while the northwest quadrant shows a mass of dry air protruding into the core of the system. The presence of dry mid-level air is revealed by the lack of significant convection to the west, with the low-level cloud bands clearly evident in the clear dry air. A microwave pass showed a well-defined microwave eye feature, with the highly asymmetric nature of the convective structure, some continued easterly vortex tilt and the dry air on the west side.

The environment remains favorable overall, with low shear, improving poleward outflow into a tutt-cell to the north, and warm sea surface temperatures. However, the presence of the dry air is hindering the system for the time being and disrupting core symmetrization.

Tropical storm 08W (Ampil) is currently tracking north-northeast under the influence of the near-equatorial ridge to the southeast, but is expected to start transitioning into a more northward track, while guided by the deep-layer subtropical ridge east of Japan. Continuing north, TS Ampil will be kept on a northerly track by the passage of TD 09W, which is also tracking north, along the western periphery of the ridge.

While the majority of the dynamical models suggest keeping the track off the shore of Japan, the most recent run of the GFS ensemble has moved the track slightly to the west again, but keeps the center offshore of the Chiba Peninsula. In addition, the actual cpa to Japan may be closer than it appears on the graphic, due to interpolation of the track between 48 and 72 hours.

In regards to the intensity forecast, there is still moderate dry air intrusion into the system forecast over the next 12-18 hours. By 24 hours, the dry air will no longer be an issue, allowing for much more rapid development, involving lower shear, warm sea surface temperatures and improved dual channel outflow. TS Ampil is expected to achieve peak intensity of 110 knots just prior to its closest approach to Japan. TS 08W is expected to steadily weaken following the closest approach to Japan, when it begins extratropical transition by 96 hours with transition to a storm-force extra-tropical low by 120 hours.

Tropical Cyclone 09W (Wukong) – Final Warning

According to the JTWC Warning number 9, sustained winds are 20 knots with gusts to near 30 knots

Animated enhanced infrared satellite imagery depicts a shallow and elliptical low level circulation center (llcc) continuing to broaden out as it tracks rapidly poleward. The system continues to track north-northwest, while being wedged between TY 08W to the southwest and strong ridge to the east. Vertical shear and outflow from TY 08W continues to hinder any potential redevelopment of TD 09W.

Analysis indicates a marginally unfavorable environment, including decreasing sea surface temperatures, weak equatorward outflow and high westerly shear.

Tropical depression 09W (Wukong) is expected to track north-northwest for the next few hours, but by 12 hours should begin its north and then northeastward turn and transit along the northwestern periphery of the ridge. As the system tracks northward, it will move out from under the westerly outflow emanating from TY 08W, resulting in a brief period of slightly improved environmental conditions for the next 12 hours or so.

The forecast calls for a steady intensity, but given the briefly improving conditions over the next 12 hours (slightly reduced shear, maintained sea surface temperatures and slightly increased ocean heat content) the system may make a short run for 35 knots before weakening again, leading to eventual dissipation by the end of the forecast period.

>>> There’s an area of disturbed weather in the South Indian Ocean, being referred to as Invest 90S, which is located approximately 277 NM northeast of Diego Garcia