Newsletter Issue 55 (May 2025)

Call for submissions – HKMetS e-bulletin “Converging divergence”

It is time to prepare for the Society’s e-bulletin “Converging divergence”. You may send your article to hkms25@meteorology.org.hk. The template for submitting a research article can be downloaded here. Not limited to research papers, articles for promoting an understanding of weather or an appreciation of the value of meteorology will also be considered. The column “Meet Our Met Team!” may be a good chance for showcasing your expertise.

The Weather of April 2025 – A relatively dry and bright April

With drier northeast monsoon affecting Hong Kong for most of the time and less moisture supply to the coast of southern China in the month, April 2025 was drier than usual in Hong Kong. The monthly mean relative humidity was 74 percent, the second lowest on record for April since 1947. The month was also sunnier than usual, the monthly total sunshine duration was 155.6 hours, about 37 percent above the normal of 113.2 hours.

Assessing the global climate in April 2025

Highlights: (1) Temperatures were above normal across most land and ocean areas in April. (2) Preliminary data suggest that global average precipitation in April was record low. (3) Northern Hemisphere snow cover extent tied for lowest on record for the month. (4) Sea ice extent was below average around both poles. (5) Global tropical storm activity was near-normal with four named storms.

Summer climate outlook for Asia in 2025
According to WMO’s report issued on March 2025, the weak La Niña event that emerged in December 2024 is likely to be short-lived. Forecasts from the WMO Global Producing Centres for Seasonal Prediction indicate that the current cooler-than-average sea surface temperatures in the equatorial Pacific are expected to return to normal. Most ENSO models predicted an ENSO-neutral condition. All the forecasts in this session of the Forum on Regional Climate Monitoring, Assessment and Prediction for Asia has also indicated a neutral phase.

Coastlines in danger even if climate target met, scientists warns

The world could see hugely damaging sea-level rise of several metres or more over the coming centuries even if the ambitious target of limiting global warming to 1.5C is met, scientists have warned. Nearly 200 countries have pledged to try to keep the planet’s warming to 1.5C, but the researchers warn that this should not be considered “safe” for coastal populations. But the scientists stress that every fraction of a degree of warming that can be avoided would still greatly limit the risks.

From sea to sky: Microsoft’s Aurora AI foundation model goes beyond weather forecasting

While a growing number of powerful new AI models provide new tools to help better anticipate the weather, a new paper published in Nature explains how a foundation model, known as Aurora, leverages the latest advances in AI to more accurately predict not just the weather, but a wide range of environmental events in a series of retrospective analyses — from hurricanes and typhoons to air quality and ocean waves.

無人機投入人工影響天氣作業

5月18日，人工影響天氣專用型“雙尾蠍A”無人機系統在四川自貢完成定型。國產大型三發固定翼無人機專用機型批量投入使用，將為我國人工增雨工作增添新的有力支援。傳統人工增雨作業依賴有人駕駛飛機，這類作業常面臨高空結冰、強對流天氣、突發湍流及低能見度等風險，對飛行安全構成嚴峻挑戰。“雙尾蠍A”搭載三台發動機與配套發電機，配備高效防除冰系統，具備全天候、中高空、長航時等作業特點，能根據不同任務需求快速調整設備配置。

Global Monthly Mean CO2

The graphs show monthly mean carbon dioxide globally averaged over marine surface sites. The Global Monitoring Laboratory has measured carbon dioxide and other greenhouse gases for several decades at a globally distributed network of air sampling sites [Conway, 1994]. The last year of data are still preliminary, pending recalibrations of reference gases and other quality control checks.

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