The very active tropical cyclone season in the North Pacific Ocean is continuing with the development of typhoons Koppu and Champi in the last few days. Typhoon Champi has just crossed the Mariana Islands, but is not expected to threaten land further in the near future. However, Typhoon Koppu is bearing down on the island of Luzon in the Philippines.
Based on latest forecasts the centre of the typhoon is likely to make landfall late on Saturday night, UK time.
However, with Typhoon Koppu the greater threat could come from heavy rainfall. Forecasts currently suggest that the typhoon will become slow moving over the Philippines and could take anything between two and five days to move away from Luzon.
The wind is expected to be destructive close to the eye as it comes onshore, with sustained winds likely to be 115mph and gusts to 160mph. Whilst the winds should weaken after landfall, rainfall will continue and be particularly heavy on the slopes of the high ground in northern Luzon. It is estimated that as much as a metre of rainfall could occur in this area which is likely to bring flooding and mudslides. A storm surge is expected near the eye of the storm.
Further south the capital Manila, which is located on lower ground on a west facing bay, could receive over 200mm rain and be subject to coastal flooding due to the strong westerly winds on the southern flank of the typhoon forcing water into the bay.
Elsewhere in the Pacific it is possible that two further tropical storms could develop in the coming days in addition to Typhoons Koppu and Champi, although no immediate impact on land areas is expected. Looking a little further ahead, some computer models expect a tropical storm to develop in the Gulf of Mexico later next week, but it is too early to give precise predictions of track and impacts at this stage.
Official warnings for the latest tropical cyclones in the western North Pacific are produced by the Japan Meteorological Agency. The Met Office routinely supplies predictions of cyclone tracks from its global forecast model to regional meteorological centres worldwide, which are used along with guidance from other models in the production of forecasts and guidance. We also provide updates on current tropical storms via @metofficestorms on Twitter.