Severe Tropical Storm Alvaro

Severe tropical storm (MFR)
Tropical storm (SSHWS)
Duration	30 December – 3 January
Peak intensity	110 km/h (70 mph) (10-min); 985 hPa (mbar)

In December 2023, the MFR began to monitor the potential for tropical cyclogenesis as Kelvin waves and Rossby waves intersect in the western portion of the agency's area of responsibility, ahead of a wet phase of the Madden–Julian oscillation (MJO); a low was forecast to develop into a moderate tropical storm south of the Mozambique Channel in these conditions.^[5] By 29 December, a monsoon trough had produced convection southeast of Beira, Mozambique that spun, as convergence of winds increases within the system's closed surface circulation.^[6] The next day, the MFR classified the system as a tropical disturbance,^[7] and in addition, the JTWC began monitoring the disturbance.^[8] Tracking southeast under the influence of a ridge, the disturbance was further upgraded to a tropical depression by the MFR on December 31.^[9] The warm core consolidated, causing the system to intensify into a moderate tropical storm and receive the name Alvaro.^[10] Moreover, the JTWC designated the storm as Tropical Cyclone 04S.^[11]

During 1 January 2024, Alvaro's maintenance of a curved band and the emergence of an eye prompted the MFR to upgrade the system to a severe tropical storm, as Alvaro continued to strengthen under favorable conditions despite vertical wind shear in the mid-level troposphere.^[12] The storm grew a central dense overcast around its ragged, inchoate eye while 269 km (167 mi) east-northeast of Europa Island, continuing east-southeast.^[13] Around 12:00 UTC, both the MFR and JTWC stated that Alvaro had peaked with sustained winds of 110 km/h (70 mph);^[14][15] the MFR also measured the system's lowest barometric pressure at 985 hPa (29.09 inHg).^[14] As the storm approached Madagascar, the cloud top pattern slowly degraded as it warmed up, with the eye gradually disappearing due to persistent wind shear.^[16] At 19:20 EAT (16:20 UTC) that day, Alvaro made landfall in Morombe District, Madagascar, bringing sustained winds of 110 km/h (70 mph) and gusts of 140 km/h (85 mph).^[3] Alvaro rapidly weakened due to the mountainous terrain of the island nation, with rainbands around the core no longer present.^[17] By 12:00 UTC of 2 January, Alvaro weakened into an overland depression and exhibited the circulation to satellite imagery, only retaining convection over the east quadrant.^[18] Alvaro re-entered the Indian Ocean on 3 January, re-intensifying back into a moderate tropical storm.^[19] Shortly thereafter, Alvaro would succumb to strong wind shear as mid-level dry air invaded the storm, despite substantial outflow boosted by a subtropical jet.^[20] By 18:00 UTC, the MFR classified Alvaro as a post-tropical depression after the storm had lost its tropical characteristics.^[21] The MFR issued its final bulletin on Alvaro on 4 January, as the system interacted with the baroclinic zone.^[22]

Anticipating Alvaro's landfall, the meteorological service of Madagascar (Meteo Madagascar) raised a yellow alert for the districts of Morondava, Manja, Morombe, and Toliara on 31 December,^[23] which would be upgraded to a red alert a day later as Alvaro made landfall.^[3] Mariners across Maintirano and Toliara were advised to stay out of sea.^[23] The mayor of Morombe reported property damage. Several parts of the city were flooded, and many residents evacuated from their homes, using schools and outlying villages as accommodation sites.^[24] Areas of southern Madagascar reported uprooted trees, torn roofs, and damaged infrastructure, necessitating international assistance.^[25] As of 5 January, nearly 26,000 people in Madagascar were affected by Alvaro, with over 9,400 displaced and relocated to 36 evacuation centers. The regions of Haute Matsiatra, Atsimo-Andrefana, Menabe, Ihorombe, and Fitovinany suffered the brunt of the storm. About 241 settlements were totally destroyed, and 426 homes were damaged in addition to 15 schools. Ten people were killed by the storm.^[26] In response to the disaster, the World Food Program allocated rice, oil, mosquito nets, and other equipment to the affected areas.^[27]

Moderate Tropical Storm Belal

Moderate Tropical Storm Belal

Satellite image Forecast map
Current storm information
As of	06:00 UTC, 13 January
Location	15°42′S 55°00′E / 15.7°S 55.0°E / -15.7; 55.0 ± 20 nm 575 kilometres (355 mi) N of Réunion
Movement	SW at 12 kn (22 km/h; 14 mph)
Currently-active Moderate tropical storm
10-minute sustained (MFR)
Sustained winds	85 km/h (50 mph)
Gusts	120 km/h (75 mph)
Pressure	991 hPa (mbar); 29.26 inHg
Currently-active Tropical storm
1-minute sustained (SSHWS/JTWC)
Sustained winds	95 km/h (60 mph)
Pressure	995 hPa (mbar); 29.38 inHg

On 11 January, the MFR marked a zone of disturbed weather, citing the conducive conditions induced by the MJO and an equatorial Rossby wave. The monsoon trough north-northeast of Madagascar had intensified several days prior, as convergence transferred moisture aloft.^[4] Concentration of convection near the center increased, particularly in the western section, as the system steered south.^[28] By the next day, the JTWC issued a Tropical Cyclone Formation Alert (TCFA) on the potential disturbance, since it was in an environment of very warm sea surface temperatures, high ocean heat content, low vertical shear, and excellent outflow.^[29] At 12:00 UTC, the MFR categorized the system as a tropical depression. Additionally, microwave imagery indicated an eye in the lower-layer,^[30] and the JTWC began issuing advisories on the system as a tropical cyclone.^[31] By 13 January, it intensified to a moderate tropical storm, prompting the MMS to name it Belal.^[32]

As the system developed, the MFR issued a yellow cyclone pre-alert for Réunion.^[33] By 13 January, the MMS issued a class I cyclone warning for Mauritius.^[34]