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Thundery showers and highs of 34°C expected in second half of September: Met Service

Thundery showers and highs of 34°C expected in second half of September: Met Service

A pedestrian with an umbrella walking in the rain in Singapore. (File photo: Jeremy Long)

SINGAPORE: Thundery showers can be expected on most days in the second half of September, mainly between the late morning and afternoon, the Singapore Meteorological Service said on Thursday (Sep 16).

For the coming fortnight, the daily temperature is forecast to range between 24 degrees Celsius and 33 degrees Celsius on most days.

Highs of around 34 degrees Celsius can be expected on a few days, said the Met Service, adding that the weather for the rest of September is forecast to be similar to that in the first two weeks of the month. 

On most days, short-duration thundery showers are forecast over parts of the island between the late morning and afternoon.

A low-pressure system predicted to develop over the northern South China Sea could trigger the development of Sumatra squalls over the Strait of Malacca and bring widespread thundery showers and gusty winds to Singapore between the predawn and morning on some days.

The overall rainfall for September 2021 is forecast to be above average over most parts of the island, the Met Service said.

The nighttime weather can be warm and humid with minimum temperatures of around 28 degrees Celsius, particularly over the south-eastern parts of the island.

This occurs when the prevailing southeast winds bring warm and humid air from the sea over the land, said the Met Service.

The prevailing Southwest Monsoon conditions in the region are forecast to persist for the rest of the month. 

Low-level winds are expected to blow mostly from the southeast or southwest, and occasionally shift to blow from the south.


In its review of the weather in the first fortnight of September, the Met Service said that thundery showers fell over parts of the island in the afternoon on most days due to strong day-time heating of land areas.

On a few days, the eastward passage of Sumatra squalls from the Strait of Malacca toward the South China Sea brought thundery showers over Singapore in the predawn and early morning.

On Sep 2, a large-scale convergence of winds in the surrounding vicinity led to the development of a Sumatra squall over the Strait of Malacca. 

"The passage of the squall brought widespread moderate to heavy thundery showers and gusty winds over Singapore in the early and predawn hours," said the Met Service.

The daily total rainfall recorded that day - 123.6mm at Ang Mo Kio - was the highest daily total for the first half of September. 

The Changi climate station recorded 119.2mm of total rainfall in the first two weeks of September. This is close to the average monthly rainfall of 124.9mm for September.

Conditions were mostly cool in the first fortnight of September, owing to the rainy weather and cloudy skies. 

The daily maximum temperature exceeded 34 degrees Celsius on four days, with the highest temperature of 34.5 degrees Celsius recorded at Marina Barrage on Sep 5. The lowest temperature of 22 degrees Celsius was recorded at Tengah on Sep 7.

Rainfall was above average over all parts of the island, said the Met Service.

"The highest anomaly of 108 per cent above average was recorded at Jurong Pier. The anomaly was lowest at Sembawang at 17 per cent above average."

Source: CNA/nh(zl)


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