By PDC’s Senior Weather
Specialist Glenn James
The Pacific Disaster Center’s (PDC Global) Tuesday, January 30, 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 1196 NM east of Port Louis, Mauritius
Tropical Cyclone 09S…is located approximately 491 NM southeast of Port Louis, Mauritius
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 32, sustained winds are 90 knots…with gusts to near 110 knots.
Animated multi-spectral satellite imagery shows that tropical cyclone 06S (Anggrek) is rapidly succumbing to strong northwesterly vertical wind shear. A dearth of recent microwave imagery has made analysis somewhat challenging, as the convection has been completely displaced away from the now exposed low level circulation center (llcc).
The past 24 hours worth of best track intensities have been reanalyzed upwards based on multiple synthetic aperture radar and ultra-high resolution passes, which indicated maximum winds roughly 10-15 knots higher than the objective and subjective fix estimates.
However, the party is now over and the system is in rapid decline as vertical wind shear is now over 30 knots, sea surface temperatures are cooler and dry air is rapidly moving in from the west. The system is racing southeast along the strong gradient between the ridge to the east and a frontal boundary about 100 NM to the south.
TC 06S is forecast to continue to accelerate towards the southeast along the tight gradient between the ridge to the east-northeast and a strong frontal boundary lurking about 100 NM south of the system. TC 06S is already being sheared apart by 35 knots of northwesterly shear and being engulfed by dry mid-level air being ushered in along the shear vector.
Model-based phase space diagrams depict a rapid extra-tropical transition (ett), starting within the next 12 hours and completing within the next 24-36 hours as the system embeds itself into the frontal boundary, moves under an extremely strong upper-level jet stream, and moves over relatively cold waters. While the system undergoes ett, it will rapidly weaken, but is expected to complete transition as a storm-force low pressure system.
Tropical Cyclone 09S
According to the JTWC warning number 1, sustained winds are 35 knots…with gusts to near 45 knots.