Tropical Cyclone 11S (Freddy) / Invest 99W
Monday, February 20, 2023

Current Snapshot

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By PDC’s Senior Weather
Specialist Glenn James

Current Tropical Cyclones:

Tropical Cyclone 11S (Freddy)…is located approximately 136 NM west-northwest of St. Denis


South Indian Ocean

Tropical Cyclone 11S (Freddy)

According to JTWC Warning number 37, sustained winds were 110 knots, with gusts to 135 knots.

TC Freddy is showing signs of weakening as it transits north of Mauritius and La Reunion. Animated multi-spectral satellite imagery depicts a fairly symmetrical system with evidence of spiral banding in the northern and southern peripheries. Analysis of the IR loop indicates deterioration of the eyewall in the southwest quadrant.

Environmental analysis indicates TC 11S to be in favorable conditions for continual tropical activity. These conditions are characterized by consistent westerly outflow aloft, low (5-10 knot) vertical wind shear, and warm sea surface temperatures.

TC Freddy continues its west-southwestward track as it transits the northeastern periphery of the ridge to the south. Copious amounts of dry air will continue to surround the system, however, TC Freddy will stay cocooned in its own moisture pocket during its forecast track.

The system will continue its west-southwestward trajectory and gradually decrease in intensity to 105 knots as it makes its approach to the east coast of Madagascar shortly after 24 hours. TC 11S is forecast to further decrease in intensity to 75 knots by 36 hours, and 50 knots by 48 hours, as it transits across the mountainous terrain of southern Madagascar.

By 72 hours, the system will be in another favorable environment over the Mozambique Channel and re-intensify to 65 knots as a result. It should be noted that the high resolution comaps-tc intensity guidance indicates rapid intensification as TC Freddy transits over the Mozambique Channel during this time.

96 hours, TC 11S will decrease to 40 knots after it makes landfall south of Beira, Mozambique. By 120 hours, TC Freddy will dissipate as a 25 knot system near the Zimbabwe-South Africa border.


Northwest Pacific Ocean

>>> There’s an area of disturbed weather being referred to as Invest 99W…which is located approximately 246 NM northeast of Manila, Philippines

Animated enhanced infrared imagery and a microwave pass shows an area of deep
convection displaced to the northeast of a low level circulation center.

Environmental analysis reveals that 99W is in a marginally favorable region for development as a result of moderate to high (15-20 knot)
vertical wind shear, offset by good poleward outflow and warm sea surface temperatures.

The vertical wind shear is expected to increase significantly to 30-40 knots between now and 24 hours, then over 40 knots by 36 hours. In addition, the mid-level moisture is expected to gradually decrease over the next 48 hours as dry air form the northeast cold surge will infringe into the circulation.

Maximum sustained surface winds are estimated at 15 to 20 knots.

The potential for transition into a significant tropical cyclone within the next 24 hours is downgraded to low.