There is currently a super typhoon in the western North Pacific called Maysak. This is a particularly strong storm for the time of year with winds in excess of 160 mph. The strongest storms in this region usually occur between August and October. Tropical storms, including typhoons, are reliant on sea surface temperatures for their energy, and as the northern hemisphere has just moved from winter to spring, this is the coldest time of year for sea temperatures. However, in the region where Typhoon Maysak formed just north of the equator, sea temperatures are almost always above 26°C, which is the critical value for tropical storm formation. Furthermore, the sea temperatures are unusually warm in this area by more than 2°C.
Super Typhoon Maysak is the fourth tropical storm of the season in the western North Pacific, the others being Mekkhala, Higos and Bavi. There has not been a year with four or more tropical storms in this region forming before the end of March since 1965. Three of the four storms have been typhoons – only Bavi remained below the 74mph threshold (the sustained wind speed required to become a typhoon). There have never been as many typhoons before the end of March in the era of reliable records (since World War II). Maysak was also the strongest typhoon to develop in March in this region since Mitag in 2002.
Maysak has now started to weaken as it moves west-northwest towards the Philippines. However, Maysak is still likely to be a typhoon when it makes landfall this weekend. There is still some uncertainty over the exact track of the storm, but the most probable path suggests the Philippines’ northern island, Luzon, is most at risk – including the capital Manila. Wind damage and flooding are likely, particularly in coastal areas.
The Eye of the Storm
Air sinks at the centre of a typhoon, resulting in the formation of an ‘eye’ which is sometimes free of cloud and mostly calm. However, on occasions small scale rotations can develop within the eye causing distinctive ‘mesovortices’ (small scale columns of rotating air) in the low level cloud pattern. These can be seen in this satellite loop of Typhoon Maysak created by the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin:
The Met Office works closely with counterparts at the Philippines weather service PAGASA, providing the latest information on computer model predictions of the likely track and intensity of Typhoon Maysak as it nears the country.
Official warnings of west Pacific tropical storms 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.
Met Office StormTracker provides a mapped picture of tropical cyclones around the globe, with access to track history and six-day forecast tracks for current tropical cyclones from the Met Office global forecast model, as well as the latest observed cloud cover and sea surface temperature. We also provide updates on current tropical storms via @metofficestorms on Twitter.
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What is happening in the central Pacific with respect to ocean surface and lower troposphere is a moderate El Niño or Modoki (from Japanese, meaning “similar but different”).
This naturally occurring El Niño event is just above the threshold for such events and is a spike upwards in a general decline in the Pacific Decadal Oscillation (PDO). As such the sea surface temperature as a positive anomaly will effect and continue to affect global temperatures for the rest of this year.
During this relaxation of the surface flow due to weakening of the Pacific trades and Walker circulation, the Eastern Pacific warm pool spreads west as a Kelvin wave. This process reduces ocean heat uptake and by heating the full globe above its equilibrium temperature causes greater radiative flux (losses) to space. This increased loss rate is unsustainable beyond a year or two, resulting in rapid global cooling as the positive anomaly fades and the normal central Pacific circulation reinstates itself. The western Pacific ‘cold tongue’ upwelling along the American seaboard marks a return of the central Pacific Ocean uptake of heat. This heat cannot simultaneously heat the cooler ocean depths and circulate around the globe as a coupled atmospheric response.
It is worth pointing out that this is a moderate El Niño event not a super El Niño so the central Pacific conditions are not exceptional by comparison with, for example, 1998.