First cyclone of the season possible in South West Pacific
Issued 22nd November 2019. The first Tropical Cyclone of the 2019-20 season could develop in the South West Pacific during the next 3 – 5 days. A low pressure system (Invest 90p) is currently located to the East of the Solomon Islands surrounded by a large area of disorganised convection. During Saturday and Sunday global models indicate the low pressure system is expected to enter a favourable environment for intensification with low vertical wind shear, warm 30C seas surface temperatures and high humidity levels. 90p is forecast to track East initially before a subtropical ridge builds to the East and steers the system towards the South on Sunday and Monday.
The ECWMF models suggests rapid intensification during Tuesday due to a highly favourable environment with maximum winds of 245km hr and a central pressure of 955hpa. At this stage ECMWF positions the potential severe cyclone of category 3 or 4 strength to be located just the the North of the Vanuatu Islands on Tuesday before rapid weakening on Wednesday over Vanuatu. The GFS model is much more modest with intensification on Monday up to 120km hr winds and 995hpa before weakening and crossing the Vanautu Islands on Tuesday. The track of the system towards the South is reasonably confident at the stage. Due to vast intensity forecasts, confidence of a Tropical Low development is High, a weak Tropical Cyclone of category 1 -2 strength is moderate and a severe category 3+ system is low. Interests throughout the Vanuatu group should closely monitor the system for further updates during the weekend. These types of tropical systems in the South West Pacific have been known to rapidly intensify in the past providing very little warning and preparation lead time. Above image via windy.com shows the current position marked with X, the likely track in red and track possibilities in yellow. The below image is the GEPS ensemble track and pressure for 90p via Tropical Tidbits.