Newsletter Issue 52 (February 2025)

The weather of January 2025 – A dry and sunny January

With the dominance of dry northeast monsoon over southern China for most of the time in the month, January 2025 was marked by dry and sunny weather in Hong Kong. The monthly total sunshine duration amounted to 222.3 hours, about 52 percent above the normal of 145.8 hours. 4.2 millimetres of rainfall were recorded in the month, only about 13 percent of the normal of 33.2 millimetres in the month.

天文台開放日2025 – 香港氣象學會會員專屬入場券登記

天文台「攜手縮小預警差距」開放日將於2025年3月22及23日(星期六及星期日)舉行，公眾人士參觀開放日須預先登記。氣象學會特別預留了40張開放日入場券予會員。如有興趣索取入場券，請使用連結填寫表格，所收集的個人資料會在開放日結束後銷毀。

日本南海海槽的地震風險及其對香港的潛在影響

香港位處歐亞板塊之內，並非處於板塊邊緣，最接近環太平洋地震帶的地方亦距離約600公里，因此不會即時受到發生在板塊邊緣或地震帶附近的巨大地震影響。然而，香港在過往也曾記錄得海嘯所帶來的輕微水位異常，而這些海嘯大都是由在南中國海或太平洋發生的地震所引發。2011年3月11日，在日本本州以東海域的日本海溝發生了9.0級大地震，當時香港錄得最高的水位異常為0.2米。由於南海海槽比日本海溝較接近香港，當該處發生大地震時，香港也可能記錄到輕微的水位異常。

January 2025: warmest January and lowest Arctic sea ice extent for the month

According to data from NOAA’s National Centers for Environmental Information, the average global land and ocean surface temperature was 1.33 degrees C above the 20th-century average, ranking as the warmest January in the 176-year global climate record. This was 0.03 of a degree C above the previous record-warm January of 2024. Last month was also notable for the low amount of sea ice covering both ends of the world. (Copernicus Climate Change Service (C3S))

February 2025 La Niña update: La Niña today, gone tomorrow?

La Niña conditions continue, but forecasters estimate a 66% chance of a switch to neutral in March–May. This is looking like a weak and short La Niña. Also, while La Niña’s ocean conditions are currently weak, the atmospheric component is fairly strong. In January, the Niño-3.4 index was -0.8 °C, according to our most reliable dataset, the ERSSTv5. This is the second month in a row that the Niño-3.4 index has exceeded the La Niña threshold of -0.5 °C, and falls into our unofficial “weak” category:

Global Seasonal Climate Update for March-April-May 2025

For March-May 2025, sea surface temperature anomalies in the Niño 3.4 and Niño 3 regions are expected to return to near-average, indicating a neutral state in the ENSO. Further west, in the Niño 4 region, the sea surface temperature anomaly is also forecast to decrease to near-average. The strength of the Indian Ocean Dipole index is likewise anticipated to be near-average. In the equatorial Atlantic, sea surface temperatures are predicted to be above average in both the northern (NTA) and southern (STA) regions.

ECMWF launches the AI Weather Quest to advance sub-seasonal forecasting with artificial intelligence

WMO is co-sponsoring the AI Weather Quest, a global competition organized by ECMWF to advance sub-seasonal weather forecasting using artificial intelligence and machine learning. Approved as a WIPPS Pilot Project by INFCOM, this initiative aligns with WMO’s mission to foster innovation and collaboration in numerical weather prediction for the benefit of NMHSs and end-users worldwide.

中國氣象局研討DeepSeek氣象應用

2月14日，中國氣象局專題交流研討如何推動DeepSeek大語言模型與氣象業務服務結合和應用問題，更好推動氣象高品質發展。會議強調，要堅持基礎先行，要堅持標準先行，要堅持創新驅動，要堅持技管結合、協同應對，要加強應用評估，要統籌發展和安全。 會上，中國氣象局相關直屬單位圍繞推動DeepSeek在氣象觀測、預報和服務中的深度融合應用做了交流發言，相關內設機構負責同志參加會議。

The weather and climate influences on the January 2025 fires around Los Angeles

A trifecta of fire-friendly climate conditions set the stage for the January 2025 fires: back-to-back wet winters that boosted vegetation, a record-dry fall, and an extremely strong Santa Ana wind event. Record-low fall precipitation had a bigger influence on the exceptionally low vegetation moisture than the near-record summer and fall temperatures. A preliminary attribution analysis concluded that long-term global warming and the development of La Niña contributed roughly equally to making the extreme fire weather conditions more likely and more extreme.

‘Fishing boat for energy’ will make hydrogen as it sails

Wind power has been rising significantly in recent years, and now accounts for about 8% of the world’s energy production. By the end of the decade, it will be the second-largest renewable source after solar, having surpassed hydropower, according to the IEA. In the UK, where wind power generation in 2024 was the largest energy source for the first time, a startup company is looking to extract even more power from offshore wind by effectively chasing after it — in a racing yacht.

Membership renewal is now more convenient

Payment through Faster Payment System (FPS) is now available (Our FPS ID: 166920512). Support your society, don’t forget to renew your membership!