User:Wxtrackercody/Blanche

Tropical Cyclone Blanche

Category 2 tropical cyclone (Aus scale)
tropical cyclone (SSHWS)
Blanche making landfall on March 6
Formed	2 March 2017
Dissipated	7 March 2017
Highest winds	10-minute sustained: 95 km/h (60 mph) 1-minute sustained: 95 km/h (60 mph)
Lowest pressure	988 hPa (mbar); 29.18 inHg
Areas affected	Cape York Peninsula, Solomon Islands, Vanuatu, New Caledonia, Tonga
Part of the 2016–17 Australian region and the South Pacific cyclone seasons

Tropical Cyclone Blanche was the first tropical cyclone to move ashore the coastline of Australia in 2017, marking the latest first instance of a landfall in the country on record. First identified on 2 March, the disorganized disturbance trekked steadily southwest amid an increasingly conducive environment, producing strong winds and record rainfall across the Tiwi Islands. The system was designated as a tropical low on 4 March, and the next day, both the Bureau of Meteorology and the Joint Typhoon Warning Center began issuing advisories on the tropical cyclone. Gradual development continued into 6 March as deep convection obscured the center, and Blanche attained its peak intensity with 10-minute sustained winds of 95 km/h (60 mph) that morning, a Category 2 on the Australian tropical cyclone intensity scale. It moved ashore the northern coast of Western Australia around 03:00 UTC, rapidly deteriorating inland. Gusty winds and substantial rainfall totals were recorded, although overall impacts were minor.

Meteorological history

Map plotting the track and intensity of the storm according to the Saffir–Simpson scale

Early on 2 March, the Bureau of Meteorology office in Darwin noted a developing tropical low in the north Arafura Sea. Later that day, the Joint Typhoon Warning Center began monitoring an area of disturbed weather characterized by disorganized convection and an elongated area of low pressure about 680 km (420 mi) northeast of Darwin, Australia. TCWC Darwin, meanwhile, began issuing advisories on the tropical low at 00:00 UTC on 4 March. Embedded within a moderate to high wind shear regime, the system was expected to track south or southwest into a more favorable environment over subsequent days. By 00:00 UTC on 5 March, the low had moved underneath an anticyclone, providing excellent outflow which offset the negative effects from continued wind shear. In accordance with satellite intensity estimates, the TCWC Darwin upgraded the low to Tropical Cyclone Blanche.

With increasing deep convection and a more consolidated center of circulation, the JTWC issued a tropical cyclone formation alert at 02:00 UTC on 5 March, upping the disturbance to Tropical Cyclone 10S shortly thereafter at 15:00 UTC. The cyclone continued its southwesterly course over subsequent hours, steered by a mid-level ridge to its northeast. At 00:00 UTC on 6 March, the TCWC Darwin upgraded Blanche to a Category 2 on the Australian tropical cyclone intensity scale, with 10-minute sustained winds of 95 km/h (60 mph) and a minimimum barometric pressure of 29.18 inHg (988 mbar); this marked the cyclone's official peak intensity. The JTWC, meanwhile, assessed a peak with 1-minute sustained winds of 95 km/h (60 mph). Around 03:00 UTC that day, Blanche moved ashore a largely uninhabited region of western Australia. Once inland, the cyclone began to weaken as its mid-level circulation became dislocated from its low-level circulation and as dry air became more prevalent. Land observations indicated that the system fell below tropical cyclone status by 09:00 UTC, marking Blanche's final advisory.

Preparations and impact

Prior to becoming a tropical cyclone, the precursor tropical low to Blanche led to a record-breaking 384 mm (15.12 in) of rainfall on Point Fawcett in the Tiwi Islands, surpassing the previous record of 265.2 mm (10.44 in) set by Cyclone Carlos in 2011. Strong wind gusts up to 95 km/h (60 mph) were recorded as well. Although expected to steer clear of the Coral Sea, some experts hoped that widespread cloudiness from the developing system would result in cooler ocean temperatures across the region, negating an ongoing coral bleaching event on the Great Barrier Reef. Passing close but ultimately west of Darwin, officials opened three public shelters and urged citizens to shelter in place as conditions deteriorated. The Darwin River Dam spillway was topped to ease potential flooding, and additional staff were allocated at local hospitals. The city recorded substantial rainfall of 145 mm (5.71 in) within a 24-hour period. On 5 March, the Department of Fire and Emergency Services issued a "blue alert" stretching from the Western Australia–Northern Territory border to Kuri Bay in the Kimberly, while a "yellow alert" was hoisted from Wyndham to Kalumburu as Blanche neared the coastline of Western Australia. Upon moving ashore, Blanche became the latest-known tropical cyclone to make landfall in Australia. Channel Point was hardest hit, with rainfall peaking at 145 mm (5.71 in). Roadways were shutdown due to street flooding. East Kimberly Regional Airport recorded 45.8 mm (1.8 in) while nearby Wyndham documented 38.8 mm (1.53 in).