Tropical Cyclone 11S / Tropical Cyclone 12 (Elvis) / Invest 96P / Invest 99S / Invest 90S – Pacific
Friday, January 31, 2025

Current Snapshot

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By PDC’s Senior Weather
Specialist Glenn James

The Pacific Disaster Center’s (PDC Global) Friday, January 31, 2025, Tropical Cyclone Activity Report…for the Pacific Ocean, the Indian Ocean, and adjacent Seas

Current Tropical Cyclones:

Tropical Cyclone 11S is located approximately 336 NM east-northeast of Port Louis, Mauritius

Tropical Cyclone 12S (Elvis) is located approximately 836 NM south-southwest of La Reunion Island – Final Warning

 

Northeast Pacific Ocean: There are no Tropical Cyclones

The last regularly scheduled Tropical Cyclone Activity Report of the 2024 eastern North Pacific Hurricane Season has been issued. Routine issuance of this section of the PDC product will resume on May 15, 2025. During the off-season, Special Tropical Weather Outlooks will be issued as conditions warrant by the NHC.

Central Pacific Ocean: There are no Tropical Cyclones

The 2024 central North Pacific hurricane season has ended. As such, the final routine Tropical Cyclone Activity Report for the 2024 season has been issued. Routine issuance of this section of the PDC product will resume on June 1, 2025. During the off-season, Special Tropical Weather Outlooks will be issued as conditions warrant by the CPHC.

 

Western Pacific, Indian Ocean, and adjacent Seas: 

South Indian Ocean

Tropical Cyclone 11S

According to the JTWC warning number 8, sustained winds were 35 knots with gusts to 45 knots

Tropical cyclone 11S continues to struggle against persistent, deep easterly shear while moving erratically over the past six hours. Animated multi-spectral satellite imagery (msi) over the past 12 hours shows the system sliding west-northwestward at a leisurely pace, then suddenly making a sharp left turn and accelerating towards the southwest. The cause of this erratic motion shift is likely the lowering of the steering level as the vortex shallowed out after losing the convective structure seen during the overnight hours. Current imagery shows an exposed low level circulation center (llcc) with disorganized convection displaced well to the west of the center. Another image showed well-defined shallow banding features arrayed in a highly symmetrical fashion around the llcc.

The environment is marginal to marginally unfavorable, with warm sea surface temperatures and weak westward outflow offset by moderate to high easterly wind shear.

Having shifted track towards the southwest, TC 11S is already beginning to level out on a west-southwest track, as a building str south of the Mascarenes pushes east, presenting the northwestern periphery of the ridge as the primary steering influence. TC 11S will continue on this west-southwestward track through 72 hours, when it will pass north of Mauritius. After 72 hours, a second str will build eastward from South Africa and assume the dominant steering role, allowing the track of TC 11S to flatten out then turn more west-northwest after 96 hours. Landfall along the northeastern coast of Madagascar in the vicinity of Toamasina is expected around 96 hours, with the system moving further inland through the remainder of the forecast.

In terms of intensity, in a similar fashion to the last couple of forecasts, the system is expected to remain steady state for the next 48 hours, as it continues to face moderate to strong easterly shear but gets a boost during diurnal convective maximums, followed by weakening as the convection blows off. Global and mesoscale models concur that the environmental shear will start to weaken around 36 hours from now, and at the same time the environment is expected to moisten and the system will move over slightly warmer waters. These positive factors will enable a period of intensification, with the system expected to peak at or above 50 knots as it approaches landfall. The actual peak in the model guidance occurs between 72 and 96 hour forecast points and is not reflected in the official forecast. After landfall, the system will rapidly weaken and dissipate over the rugged terrain of central Madagascar.

 

Tropical Cyclone 12S (Elvis) – Final Warning

According to the JTWC warning number 6, sustained winds were 35 knots with gusts to 45 knots

Animated multi-spectral satellite imagery shows the low level circulation (llc) has become ragged, elongated and fully exposed as the central convection is sheared 100+ NM southeastward. Additionally, a cold front has developed to the northeast and is trailing the llc.

Analysis indicates TC 12S has transformed into a subtropical system and is expected to rapidly transition into an extra-tropical system by with a cold-core low and an expanding wind field by 12 hours.

 

Southwest Pacific Ocean

>>> There’s an area of disturbed weather being referred to as Invest 96P, which is located approximately 100 NM southeast of Cairns, Australia

Animated multi-spectral satellite imagery depicts a poorly organized low level circulation center with weak and disorganized convection. The low level circulation center (llcc) has been repositioned into a relatively cloud free area surrounded by tightly curved banding. The new llcc is in good agreement with gfs fields and is indicative of an immature circulation that has been moving erratically thus far.

Environmental analysis reveals that Invest 96P is in a favorable environment for further development with good equatorward outflow aloft, warm sea surface temperatures, and low (5-10 knot) vertical wind shear.

Maximum sustained surface winds are estimated at 23 to 28 knots.

The potential for the development of a significant tropical cyclone within the next 24 hours remains low.

 

South Indian Ocean

>>> There’s an area of disturbed weather being referred to as Invest 99S, which is located approximately 436 NM west-northwest of Cocos Islands.

Animated multi-spectral satellite imagery (msi) depicts an elongated area of low level rotation with deep flaring convection in the north-northwestern quadrant. Strong westerly flow along the 10S latitude are helping 99S gain more momentum in the next 24-36 hours. A scatterometry pass reveals a wind field of 25-30 knot winds in the northern portion of the semicircle approximately 150 NM from the circulation center, with areas of 15-20 knot winds beginning to wrap into the llcc.

Environmental analysis indicates that Invest 99S is in a favorable environment for further development due to warm sea surface temperatures, good poleward outflow aloft, and is in an area of low to moderate (15 to 20 knots) vertical wind shear.

Global models are in  agreement that Invest 99S will continue to rapidly consolidate and take a general south-southwestward track over the next 24 hours.

Maximum sustained surface winds are estimated at 28 to 33 knots.

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

 

>>> There’s a second area of disturbed weather being referred to as Invest 90S, which is located approximately 315 NM north-northwest of Broome, Australia

Animated multi-spectral satellite imagery (msi) depicts a broad area of elongated rotation with flaring convection to the northeast. Strong westerly flow along 10S to 11S latitude is helping Invest 90S gain more momentum within the next 24-36 hours. An ascat scatterometry pass reveals an area of 15-20 knot winds beginning to wrap into the weakly defined circulation center. Approximately 100 NM to the north there is a wind field of strong 20-25 knot winds.

Environmental analysis indicates that Invest 90S is in a favorable environment for further development due to very warm sea surface temperatures, good poleward outflow aloft, and low to moderate (15 to 20 knots) vertical wind shear.

Global models are in good agreement that Invest 90S will quickly consolidate and track west-southwestward over the next 24-36 hours.

Maximum sustained surface winds are estimated at 28 to 33 knots.

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