Consecutive days of rain in this year’s “plum rain” season may start in the second half of this month, the Central Weather Bureau (CWB) said yesterday.
The season, which generally lasts from May to June, was given its name because the rain comes at about the time when the plums south of China’s Yangtze River ripen. Accumulated rainfall during the plum rain season usually accounts for between a quarter and a third of Taiwan’s total annual rainfall.
Cheng Ming-dean (鄭明典), director of the bureau’s weather forecast center, said the bureau had forecast a 50 percent chance that the total accumulated rainfall during the two-month period would fall within the normal range. However, he said there was a 30 percent chance that the rainfall would be below average, and a 20 percent chance of above-average rainfall.
Meanwhile, the bureau forecast that temperatures during the plum rain season would likely be within the normal range or slightly higher than average.
Asked if the nation could experience a plum rain season with accumulated rainfall of less than 500mm, Cheng said it was not likely.
“The chances for that to happen are very low,” he said. “It is still a rainy season and we will still have a lot of rain.”
Cheng said that years that were below average still had about 300mm of accumulated rainfall.
Cheng said the nation would start seeing consecutive rainy days — a common feature in the plum rain season — from the second half of next month, which is slightly later than usual. Heavy to strong precipitation is likely from the second half of this month to mid-June, he added. Cheng said the bureau considers four consecutive days of rain a typical feature of the season, with daily accumulated rainfall exceeding 9mm.
Cheng also said that a tropical convection system near the south of the nation has been active for the past few months, adding that those in the south need to beware of potential damage from heavy to torrential rain.
While the nation has yet to see rainy weather in the plum rain season, it experienced extreme weather yesterday. Records from the bureau showed that several cities around the nation had daytime highs exceeding 30oC at about noon.
The highest temperature, 34.8oC, was recorded in Dawu (大武) in Taitung County, accompanied by a foehn wind, a “rain shadow” wind that can dramatically raise temperatures. It was followed by Chiayi and Taipei, which saw temperatures of 32oC and 31.9oC respectively. Temperatures in Banciao, Greater Tainan, Greater Taichung, Henchun (恆春) and Greater Kaohsiung also rose above 30oC.
The high temperatures dropped when the rain front approached the nation last night, which was also the first frontal system in the plum rain season.
Chances of showers are high in the nation’s west and northeast coast during the daytime today. Highs of 22oC in the north and northeast, 25oC in central areas, 26oC in the east and 28oC in the south are expected.