By PDC’s Senior Weather
Specialist Glenn James
The Pacific Disaster Center’s (PDC Global) Tuesday, October 24, 2023, Tropical Cyclone Activity Report…for the Pacific Ocean, the Indian Ocean, and adjacent Seas
Current Tropical Cyclones:
Tropical Cyclone 18E (Otis) …is located approximately 175 miles south-southeast of Acapulco, Mexico
Tropical Cyclone 01P (Lola) …is located approximately 126 NM north of Port Vila, Vanuatu
Tropical Cyclone 06B (Hamoon)…is located approximately 96 NM south-southwest of Chittagong
Tropical Cyclone 05A (Tej) …is located approximately 159 NM west-southwest of Salalah, Oman – Final Warning
Northeast Pacific Ocean:
Tropical Cyclone 18E (Otis)
OTIS EXPECTED TO BECOME A HURRICANE BEFORE REACHING THE COAST OF
According to the NHC advisory number 8A…
Otis is moving toward the north-northwest near 8 mph (13 km/h), and this general motion is expected during the next couple of days. On the forecast track, Otis is expected to reach the coast of southern Mexico late tonight or Wednesday.
Maximum sustained winds are near 65 mph (100 km/h) with higher gusts. Strengthening is forecast, Otis is expected to become a hurricane before it reaches southern Mexico.
Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center.
Central North Pacific:
There are no tropical cyclones, nor any areas of disturbed weather under investigation by the CPHC at the time of this writing.
Western Pacific, Indian Ocean and adjacent Seas:
Tropical Cyclone 01P (Lola)
According to the JTWC warning number 11…sustained winds were 115 knots, with gusts to 140 knots
Animated enhanced infrared (eir) satellite imagery shows that the eye present just six hours ago has already disappeared and filled in, leaving behind a remnant warm spot in the most recent eir. The most recent microwave imagery revealed a well-defined upper-level microwave eye feature, but the low-level microwave eye was barely visible and offset slightly to the northeast. The image showed an irregular eyewall, open to both the north and south, and strong convection in the eastern eyewall.
The environment looks supportive, with low deep-layer shear, relatively warm sea surface temperatures and robust poleward outflow. However, high (30-40 knots) mid-level shear and very dry air will be the driver of the systems demise and are already beginning to have an impact. TC 01P is moving southwest along the periphery of a deep-layer subtropical ridge centered to the east.
TC 01P will track southwest through the northern portion of the Vanuatu Islands over the next 12 to 18 hours, then continue southwest into the open waters west of Vanuatu along the western side of the steering ridge. Around 36 hours the system will turn southward then curve south-southeastward by the end of the forecast period as it tracks ahead of an approaching mid-latitude system developing off the coast of Australia.
Based on satellite imagery analysis, TC 01P likely peaked, and has already begun to weaken, as the mid-level shear and dry air begin to take their toll. All global and mesoscale models suggest this is going to be one of the most dramatic cases of rapid weakening on record.
High-resolution models indicate that high winds will lead to a full decoupling of the vortex within the next 24 hours, which along with increasing dry air smothering any chance of convective development, will allow for an extremely rapid weakening of the system. The forecast calls for dissipation below warning criteria by 72 hours, as the system passes over New Caledonia, but a faster rate of weakening is possible with only a very weak remnant vortex passing near or over New Caledonia around 72 hours.
North Indian Ocean
Tropical Cyclone 06B (Hamoon)
According to the JTWC warning number 6…the system had sustained winds of 75 knots, with gusts to 90 knot
Tropical cyclone 06B (Hamoon) continues to present a robust appearance in the enhanced infrared (eir) imagery, with persistent deep convection and a single hot tower in the southwest portion of the circulation persisting for the past four hours. However, the eir loop is deceiving as it obscures the low level circulation center (llcc). A fortuitous color enhanced image shows exposed low level banding features wrapping into a center, which is partially exposed to the west of the upper-level microwave eye. This suggests the vortex is already beginning to decouple.
Environmental conditions are increasingly hostile, with high southwesterly shear and mid-level dry air offsetting beginning to exert their influence and overwhelm the robust poleward outflow and warm sea surface temperatures.
TC 06B is forecast to continue tracking towards the generally towards the northeast through the forecast period. Landfall in the vicinity of Coxs Bazaar is anticipated within the next six to eight hours. With the most recent microwave imagery suggesting the vortex is already starting to decouple due to 30+ knots of southwesterly shear, the system is forecast to rapidly weaken as it approaches landfall. An intensity between 60-65 knots is expected as the system crosses the coastline.
Rapid weakening will occur thereafter as the system is sheared apart by the strong shear from above, and the rugged terrain tears the low-level vortex apart at the surface. The system is expected to dissipate between 36 and 48 hours along the border between Myanmar and eastern India.
Tropical Cyclone 05A (Tej) – Final Warning
According to the JTWC warning number 16…sustained winds were 35 knots, with gusts to 45 knots
The center of TC 05A likely made landfall in southeastern Yemen within the past few hours, and deep convection is collapsing due to land interaction and an increase in southwesterly vertical wind shear. Animated enhanced infrared (eir) satellite imagery depicts the majority of deep convection now displaced to the northeast of the low-level circulation center.
TC 05A is expected to follow the lower to mid-level flow over the next 24 hours as it weakens due to passage over land and moderate vertical wind shear. There is a slight chance that the low-level center will track along the coast as it is blocked by mountainous terrain to the north, although the current forecast anticipates an eventual turn of the remnant circulation to the north. Regardless of the exact track, the system will steadily dissipate to below warning level intensity within 24 hours.