Rare Winter Echoes Appear: Weather Battle Unveiled by Cheng Ming-dian with Southern Branch Trough and Inversion
Cheng Ming-dian, a former director of Taiwan’s Central Weather Bureau, recently noted significant weather phenomena affecting the island. On January 19, 2023, he shared radar images that indicated unusual patterns during Taiwan’s winter season.
Rare Winter Echoes and Weather Insights
The radar images displayed a high number of echoes, a scenario not commonly seen in Taiwan’s winter months. This surge in radar activity is linked to the southward movement of cloud systems, resulting in increased moisture and localized short rain showers across the island.
Conditions and Implications
- The radar echoes primarily originated from the coastline, suggesting a change in airflow around Taiwan’s topography.
- Cheng indicated that these conditions might point to the presence of an inversion layer over Taiwan.
- He emphasized the importance of the southern branch trough, which is associated with increased rainfall potential.
- However, this inversion layer could counteract the rainfall, creating a complex interplay of weather dynamics.
Cheng further elaborated that the southern branch trough impacting Taiwan is particularly unique. An analysis of the 500 hPa height field showed that it is not a singular trough but a series of short-wave troughs and ridges. This configuration indicates a state of “positive pressure instability,” predominantly fueled by jet stream dynamics.
Future Weather Forecast
As the southward moisture continues to advance, the likelihood of rain is expected to increase, particularly on January 20, 2023. The Taiwan Typhoon Forum, a popular weather-focused Facebook page, corroborated this forecast, advising locals to prepare for potential rainfall.
Weather Advisory
With the northeast monsoon prevailing, cooler and more humid conditions will envelop Taiwan. Residents are advised to stay vigilant regarding temperature fluctuations and bring rain gear to accommodate the expected short-lived showers.
