Hot, dry weather persists |27 May 2005

“Interestingly, most months of this year were warmer by 0.5 to 1.0 degree Celsius above the norm, with May achieving a new extreme record maximum temperature of 33.5 degrees,” said a statement from the National Meteorological Services (NMS).

The previous extreme maximum temperature for May was 33.3 degrees measured in 1987. The record extreme maximum temperature overall stands at 34.4 degrees measured in November 1974 at the Seychelles International Airport.

The driving force of the abnormal weather so far this year is associated with the exchange of excess heat between the ocean and atmosphere as a result of the relatively weak El Nino conditions prevailing, said the NMS.

El Nino conditions mean that the tropical ocean is warmer than normal.
“The dryer conditions that have prevailed during the first half of the year are not totally surprising because it tends to agree with the fact that during El Nino years, rainfall tends to decrease in the rainy season and increase in the dry season,” the statement noted.

The direct cause of the extreme maximum temperature recorded in May is believed to be due to an abnormal weather pattern forming between Agalega and Mahe which inhibited the proper onset of the cooler southeasterly flow. “This weather system moved slowly westward and in the process allowed warmer northwesterly winds to blow over Mahe and the inner islands.”

The NMS, in conjunction with work from other climate centres, has predicted normal to slightly above normal rainfall for the upcoming dry season for June-September, saying there is a 75 percent chance that it will not be an extreme dry season.

“This marks a shift from the normal conditions,” said Denis Chang-Seng, acting assistant director at the NMS.

However, that does not mean that there won’t be days or weeks of noticeable dry spells. It is also not anticipated that the coming southeast monsoon winds will be stronger than normal, although there could be strong surges at times, the NMS said.