Tropical Cyclone "Berguitta," the third named storm of the 2017-18 South-West Indian Ocean cyclone season, is on its way toward Mauritius and La Reunion. Although this system is now slowly weakening, it's expected to maintain its tropical cyclone winds and make landfall over Mauritius sometime after 18:00 UTC on January 17 and over La Reunion before 06:00 UTC on January 18 as Category 1 hurricane equivalent. Residents of both islands should not underestimate this storm and be ready for heavy rain, serious wind damage and power outages that could last a few to several days.
Berguitta formed January 13 and was a strengthening quasi-stationary system located north of Rodrigues before it started moving toward Mauritius. Early forecast tracks were in notable disagreement, with RSMC La Reunion calling for a track west of the islands and JTWCs calling a direct hit. This is basically what we see now, less than 36 hours before Mauritius landfall. Although track can change, dynamic model guidance is showing improvement in the track uncertainty with ECMWF, GFS, JGSM and the GFS ensemble solutions all closely grouped together over the next 48 hours with a track impacting both Mauritius and La Reunion. Current JTWC track (09:00 UTC) is hedged toward these solutions with high confidence.
Residents of both islands should prepare for a tropical cyclone on an upper edge of Category 1 hurricane equivalent, very dangerous winds that can damage roofs, shingles, vinyl siding and gutters even on well-constructed frame homes. Category 1 hurricane winds can snap large branches of trees while shallowly rooted trees may be toppled. Extensive damage to power lines and poles is likely, resulting in power outages that could last a few to several days.
Tropical Cyclone "Berguitta" 3-hr precipitation accumulation at 09:00 UTC, January 16, 2018. Credit: earth.nullschool.net
Tropical Cyclone "Berguitta" JTWC forecast track at 09:00 UTC on January 16, 2018
Tropical Cyclone "Berguitta" on January 16, 2018. Credit: NASA Terra/MODIS
As of 09:00 UTC on January 16, the center of Tropical Cyclone "Berguitta" was located approximately 507 km (315 miles) of Port Louis, Mauritius and has tracked westward at 9 km/h (6 mph) over the past six hours, according to data provided by the Joint Typhoon Warning Center (JTWC).
Animated multispectral satellite imagery depicts a tightly wound cyclone with a cloud filled ragged eye feature.
At the time, Berguitta had maximum sustained winds of 176 km/h (109 mph), based on multiagency current intensity Dvorak estimates ranging from T5.0 to T5.5 and a 02:49 UTC Satcon estimate of 179 km/h (111 mph).
Over the next 12 to 24 hours, Berguitta is expected to gradually weaken. However, sea surface temperatures in the region are warm (28 °C / 82.4 °F) and conducive to support tropical cyclone strength winds for the next 72 hours.
Berguitta is expected to begin interacting with an approaching mid-latitude trough around 09:00 UTC on January 20 and fully transition into an extratropical system by 09:00 UTC, January 21.
Featured image: Tropical Cyclone "Berguitta" on January 16, 2018. Credit: NASA Terra/MODIS