The Pacific Disaster Center’s (PDC Global) Monday, September 15, 2025, Tropical Cyclone Activity Report…for the Pacific Ocean, the Indian Ocean, and adjacent Seas
Current Tropical Cyclones:
Tropical Cyclone Mario is located about 165 miles west-northwest of Socorro Island
Northeast Pacific Ocean:
Tropical Cyclone Mario
MARIO CONTINUES MOVING WEST-NORTHWESTWARD FARTHER AWAY FROM SOCORRO ISLAND
According to the NHC advisory number 12
Mario is moving toward the west-northwest near 12 mph (19 km/h). This general motion with a gradual turn towards the northwest is expected over the next few days.
Maximum sustained winds remain near 60 mph (95 km/h) with higher gusts. Little significant change in strength is anticipated today, followed by gradual weakening beginning on Tuesday. Mario could become a post-tropical cyclone on Wednesday.
Tropical-storm-force winds extend outward up to 35 miles (55 km) from the center. The estimated minimum central pressure is 995 mb (29.39 inches).
Off the coast of Southwestern Mexico:
>>> An elongated trough of low pressure located several hundred miles off the coast of southern Mexico is producing disorganized showers and thunderstorms.
Environmental conditions appear conducive for gradual development of this system, and a tropical depression could form by the middle to latter part of this week as it moves west-northwestward at 10 to 15 mph over the central east Pacific.
*Formation chance through 48 hours…low…20 percent
*Formation chance through 7 days…medium…60 percent
Central Pacific Ocean: There are no Tropical Cyclones
Tropical cyclone formation is not expected during the next 7 days.
Western Pacific, Indian Ocean, and adjacent Seas: There are no Tropical Cyclones
Western Pacific
>>> There’s an area of disturbed weather being referred to as Invest 98W, which is located approximately 515 NM east-southeast of Da Nang, Vietnam
Animated multi-spectral satellite imagery (msi) depicts a poorly defined low-level circulation with flaring convection in the northern and western peripheries. A 150217z metop-c ascat pass revealed a broad low level circulation with 10-15 kt winds wrapping from the northern portion of the system.
Environmental analysis indicates marginally favorable conditions for
development with low vertical wind shear (5-10 kts), and warm (29-30
c) sea surface temperatures, offset by weak equatorward outflow aloft
and the broad nature of the wind field.
Global deterministic models are in agreement that 98W will propagate northwestward through the South China Sea with little development. Ensemble models are also in agreement on a northwestward track over the next 24 hours with ECENS being more aggressive with the intensity of the system.
Maximum sustained surface winds are estimated at 13 to 18 knots.
The potential for the development of a significant tropical cyclone within the next 24 hours remains low.
>>> There’s a second area of disturbed weather being referred to as Invest 99W, which is located approximately 90 NM east-northeast of Legazpi
Animated enhanced infrared imagery (eir) depicts a fully exposed low level circulation with slight convection just south of the center. 99W
currently sits within a much broader overall area of cyclonic turning
throughout the Philippines Sea.
Environmental analysis indicates a moderately favorable environment with warm (30 c) sea surface temperatures, moderate equatorward outflow aloft, and low (10-15 kts) vertical wind shear impacting the system from the northwest.
Global deterministic and ensemble model guidance is in good agreement on a north-northwestward track as 99W continues to intensify along the coast of Luzon.
Maximum sustained surface winds are estimated at 13 to 18 knots.
The potential for the development of a significant tropical cyclone within the next 24 hours is low.
