Plum rain front expected today
The CWA has launched a text messaging system to warn about danger posed by rivers when there is short-duration, intense rainfall
The first plum rain front is expected to arrive today, with the northeast monsoon to lower daytime temperatures in northern Taiwan to 22°C, the Central Weather Administration (CWA) said yesterday.
The season generally lasts from May to June.
Rain began yesterday afternoon, with heavy showers in mountainous areas, Yilan County and the northeast coast, the agency said.
The chance of rain would be high nationwide today and tomorrow due to the arrival of the front, CWA forecaster Liu Yu-chi (劉宇其) said, adding that rain would ease after the front leaves on Friday.
Another front from southeast China would arrive by Monday next week, Liu said, adding that further observations are needed to predict the possible effects.
While temperatures in some areas reached 34°C yesterday, temperatures in northern Taiwan are to drop by about 10°C today due to the northeast monsoon, the agency said.
Temperatures are to rebound on Friday after the front eases, it said.
The front, which originated in southern China, has large thunderstorm cells and a lot of lightning, so the weather is expected to be unstable, Liu said.
People should beware of shortduration, intense rainfall, he said.
CWA Weather Forecast Center director Chen Yi-liang (陳怡良) said that total precipitation during the plum rains this year would be normal or slightly below normal, while average temperatures would be normal or slightly warmer.
The nation had a warmer spring this year, with an average temperature of 22°C, higher than the usual 20.8°C average for the period, Chen said, adding that it was also the second-warmest spring since 1951.
Total rainfall this spring was only 80 percent of average, he said.
“Based on our weather simulation model and those of other countries, we expect a weakening El Nino effect and a gradually developing La Nina effect,” Chen said.
In Taipei, normal rainfall this month ranges between 166.8mm and 291.6mm, he said.
While there have not been significant changes in total rainfall over the past few plum rain seasons, short-duration, intense rainfall incidents have been more frequent, he said.
The agency has launched a Public Warning System feature that sends text messages about danger posed by swelling rivers when there is short-duration, intense rainfall in mountainous areas, Chen said.
When a river swells, people are often left with little time to flee, leading to people becoming trapped or being swept away, the CWA said.
The agency conducted a two-year trial before the official launch.
The alert was issued 117 times last year amid the trial run, with more than 60 percent of text messages giving early warning with an average lead time of about 53 minutes, it said.
The system has been expanded to 24 rivers in 11 administrative regions and the agency offers daily forecasts for the associated catchment areas, it added.