Cyclone Beni - Meteorological History

Meteorological History

Severe Tropical Cyclone Beni originated from a broad low-pressure area positioned within a monsoon trough was located northeast of the Santa Cruz Islands in mid to late January. Drifting to the west, and while under a conductive environment, the system gained organization. Late on January 20, the Fiji Meteorological Service's Regional Specialized Meteorological Center in Nadi, Fiji, started to monitor the disturbance, classifying it tropical depression. The system entered less favorable conditions for further development while in the vicinity of the Solomon Islands. After conditions once again became conductive for development, the storm gained enough organization to be upgraded to tropical storm strength and was given the name Beni on January 25.

Upon being named, the Joint Typhoon Warning Center classified the system as Tropical Cyclone 12P. The system initially moved west-southwest, around the northwestern boundary of a ridge. Although further intensification was suppressed by wind shear and diurnal minimum, interaction with the ridge enabled the system to undergo a small clockwise loop. Subsequently, the cyclone resumed a more southerly motion. Encountering more favorable conditions, Tropical Cyclone Beni started to intensify. According to RMSC Nadi, Beni reached Category 2 strength on the Australian intensity scale on January 27. At 000 UTC the next day, the JTWC remarked that the storm had developed hurricane-force winds of 85 mph (135 km/h). Around that time, RMSC Nadi indicated that Beni had developed winds of a Category 4 cyclone. Now at the southwest side of the ridge, the cyclone made a turn towards the southeast during the morning hours of January 28.

Continuing to intensify, the JTWC reported that afternoon that Cyclone Beni had developed winds equal to a Category 2 hurricane on the Saffir–Simpson hurricane wind scale while a ragged eye briefly appeared on satellite imagery. The eye feature re-developed the next day, this time better defined and smaller in diameter. Based on data from RMSC Nadi, Cyclone Beni reached its peak intensity early on January 29 with maximum sustained winds of 125 mph (205 km/h ), gusts of 150 mph (250 km/h) and a minimum pressure of 920 mbar (27 inHg). These winds made Beni a Category 5 tropical cyclone, the highest possible vrating on the Australian scale. At the time of its peak, the cyclone was centered about 200 km (120 mi) north of New Caledonia. At that time of peak, gale–force winds extended 120 nmi (220 km) from the center of Beni. At 0600 UTC the same day, the JTWC reported that Beni had attained its peak intensity of 145 mph (230 km/h) (equal to a Category 4 hurricane) and a peak pressure of 916 mbar (27.0 inHg).

After attaining peak intensity, a combination of cooler sea surface temperatures and increased wind shear resulted in Beni starting a weakening trend. Meanwhile, a trough accelerated Beni. The cyclone was continuing to move southeast while passing fairly close to Vanuatu . However, a strengthening ridge slowed Beni down and allowed the cyclone to move towards the south and then southwest, moving it away from Vanuatu. Rapid dissipating due to wind shear, the cyclone's central dense overcast was soon completely separated from Beni's center of circulation. On January 30, the storm passed south of New Caledonia and even closer to the commune of L'Île-des-Pins, but by this time, RMSC Nadi reported that Cyclone Beni was only a marginal Category 1 system with winds of 40 mph (65 km/h) and a pressure of 994 mbar (29.4 inHg). The system was further downgraded into a tropical depression the same day while located 240 nmi (440 km) southwest of New Caledonia.

The depression continued to move towards the west, and subsequently northwest, across the Coral Sea, and on February 1, crossed the 160th meridian east from the South Pacific basin into the Australian region. In an area of once again increasing sea surface temperatures and warm air, convection developed over the center. TCWC Brisbane reported that the system was once again briefly upgraded into tropical cyclone status. At this time the pressure of the cyclone was 995 mbar (29.4 inHg). However, vertical wind shear once again took its toll on Beni, and the circulation center decoupled from thd deep convection and the storm's strongest winds. Consequently, Beni was once again downgraded into a depression, just 12 hours after its re-classification as a tropical cyclone. The remnant low of Severe Tropical Cyclone Beni made landfall near Mackay on February 5.