Tropical Cyclone 06S (Anggrek) / Invest 90P
Saturday, January 20, 2024

Current Snapshot

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By PDC’s Senior Weather
Specialist Glenn James

The Pacific Disaster Center’s (PDC Global) Saturday, January 20, 2024, Tropical Cyclone Activity Report…for the Pacific Ocean, the Indian Ocean, and adjacent Seas

Current Tropical Cyclones:

Tropical Cyclone 06S (Anggrek)…is located approximately 250 NM west of the Cocos Islands


Northeast Pacific Ocean:

The North Pacific hurricane season officially ended on November 30, 2023. Routine issuance of the Tropical Weather Outlook will resume on May 15, 2024. During the off-season, Special Tropical Weather Outlooks will be issued as conditions warrant.

The eastern Pacific basin hurricane season was above normal, with 17 named storms, of which 10 were hurricanes and eight of those major hurricanes.

From August 16 to 21, Tropical Storm Hilary brought widespread heavy rainfall and flooding to Southern California, with some areas receiving up to 600% of their normal August rainfall. Hilary resulted in the first ever issuance of Tropical Storm Watches and Warnings for the Southern California coastline by NOAA’s National Hurricane Center. In addition, the Center distributed key hazard focused messages for Hilary in Spanish through the agency’s new language translation project.

Hurricane Otis made landfall near Acapulco, Mexico, on October 25 as a category-5 hurricane, with sustained winds of 165 mph. Otis holds the record as the strongest land falling hurricane in the eastern Pacific, after undergoing rapid intensification in which wind speeds increased by 115 mph in 24 hours.

Central North Pacific:

The central North Pacific hurricane season officially ended on November 30, 2023. Routine issuance of the Tropical Weather Outlook will resume on June 1, 2024. During the off-season, Special Tropical Weather Outlooks will be issued as conditions warrant.

The central Pacific basin had a near-normal season with four tropical systems traversing the basin.

Hurricane Dora, a category-4 storm, passed south of Hawaii in early August, marking the first major hurricane in the central Pacific basin since 2020. The strong gradient between a high pressure system to the north and Dora to the south was a contributing factor to the wind-driven, fast-moving wildfires in Hawaii.

Western Pacific, Indian Ocean and adjacent Seas:

South Indian Ocean…

Tropical Cyclone 06S (Anggrek)

According to the JTWC warning number 11, sustained winds are 70 knots…with gusts to near 85 knots.

Animated multi-spectral satellite imagery (msi) depicts tropical cyclone 06S (Anggrek) tracking west-southwest at 2 knots over the last 12 hours, significantly differing from the previous forecast, anticipating a track of west-northwest. The msi shows strong convective towers developing to the north of the center and wrapping upshear, and a nascent warm spot or eye feature beginning to appear. A microwave pass revealed a small microwave eye feature, with some slight west-northwest tilt with height.

The apparent intensification suggests that actual wind shear is less than the global models had anticipated (20 knots). upper-level outflow remains modest primarily limited to the immediate region around the system along with a weak poleward push.

tropical cyclone 06S (Anggrek) is forecast to track west-northwest through 36 hours, then travel due west through 48 hours before continuing south-southwest at 2 knots for the remainder of the forecast period. This is due to a competing steering environment with a ridge to the north and a ridge to the south. Through 48 hours, the subtropical ridge is expected to build, forcing the north-northwest motion, then weaken as the ridge to the north forces the system to the south. After 72 hours, the system turns southwestward as it is drawn towards a weakness in the ridge to the south, induced by the approach and passage of a mid-latitude trough to the south.

In terms of intensity, in the near-term, the system is expected to intensify to approximately 75 knots with sea
surface temperatures support but will weaken to approximately 65 knots gradually through 36 hours due to dry air entrainment from the west and cold seawater upwelling resulting from the slow movement of the storm. Wind shear is also expected to increase between 12-36 ours before weakening through the end of the forecast period, which combined with improved upper-level outflow, will allow for a renewed intensification trend after 72 hours.


>>> There’s an area of disturbed weather being referred to as Invest 90P…which is located approximately 374 NM east-northeast of Willis Island, Australia.

Animated IR satellite imagery depict a formative spiral banding wrapping into a well defined low level circulation center.

Upper-level analysis reveals a marginally favorable environment,  with weak poleward divergence aloft, warm sea surface temperatures, offset by high vertical wind shear (20-30 knots).

Global models are in good agreement that 90P will continue tracking southwestward and further develop over the next 24-36 hours.

Maximum sustained surface winds are estimated at 27 to 33 knots.

The potential for the development of a significant tropical cyclone within the next 24 hours upgraded to high.