Monthly Weather Bulletin

MOnthly weather bulletin

SEPTEMBER 2007

1. SUMMARY

Generally, most places in the country received average to above average rainfall amount during this month. The temperature, amount of solar radiation and evaporation rates were recorded above average for most places in the country.

2. RAINFALL

Climatologically, September correspond to the end of southwest monsoon. In general, most places were wet and received normal to much above normal rainfall. Spatially, northwestern regions received more rainfall in Peninsular Malaysia. Over East Malaysia, central Sarawak and western Sabah received more rainfall than the rest. Temporally, more rainfall was distributed during the first half of the month.

Heavy rainfall event on 7^th ,8^th and 9^th September 2007 over northwestern and central part as well as eastern Johor had caused floods particularly in the low lying areas.

Speed convergence of northwesterly wind coupled with high moisture content and unstable atmospheric conditions had caused three days heavy rainfall over northern regions on the 14^th to 16^th September 2007. This phenomenon had caused floods particularly in low lying areas in Kedah and Penang.

In Peninsular Malaysia, Bayan Lepas recorded the highest monthly rainfall of 480.4mm while Muadzam Shah recorded the lowest monthly rainfall of 79.2mm. Pulau Langkawi registered the highest daily rainfall of 97.6mm on the 7^th.

In East Malaysia, Bintulu recorded the highest monthly rainfall of 463.8mm while Labuan recorded the lowest monthly rainfall of 57.8mm. Kota Kinabalu registered the highest daily rainfall of 105.2mm on the 27^th.

The number of rain days ranged from 10 days in Kluang to 20 days in Kota Bharu in Peninsular Malaysia; 17 days in Sibu to 24 days in Bintulu in Sarawak ; and from 13 days in Sandakan to 22 days in Labuan in Sabah.

3. TEMPERATURE

Generally, the country recorded normal temperature during this month.

The monthly mean temperature of lowland areas varied from 26.0°C at Kuala Krai to 27.8°C at Labuan. The largest positive deviation from normal was +1.1°C recorded at Kluang and the largest negative deviation was -0.6°C at Bintulu.

The monthly mean minimum temperature of lowland areas ranged from 22.7°C at Kuala Krai to 24.9°C at Labuan. The lowest temperature of 21.1°C was recorded at Kuala Krai.

The monthly mean maximum temperature of lowland areas ranged from 30.6°C at Tawau to 33.1°C at Temerloh. The highest temperature of 35.1°C was recorded at Kluang and Sandakan.

Temperature in Cameron Highlands ranged from 14.3°C to 25.0°C with a mean 17.8°C. The deviation from normal was +0.1°C.

4. SOLAR RADIATION

During this September, about 75% places in the country received above normal amount of solar radiation.

The mean solar radiation varied from 13.81MJm^-2 in Senai to 20.38MJm^-2in Kota Bharu. The largest positive and negative deviations were recorded at +3.99MJm^-2 in Subang and at -0.70MJm^-2 in Senai.

Cameron Highlands recorded the mean daily solar radiation at 12.92MJm^-2 with the deviation of +0.31MJm^-2.

5. EVAPORATION

Overall, the evaporation rate over the country was above normal. The mean daily evaporation rates in lowland areas varied from 2.7 mm/day in Mersing to 4.8 mm/day in Kuala Terengganu and Labuan. The largest positive deviation was +0.7mm/day at Senai and the largest negative deviation was -0.8mm/day at Mersing and Bintulu. The rate in Cameron Highlands was 2.4mm/day with a deviation of +0.6mm/day.

Figures and tables:

Figure 1 : Rainfall Map for Peninsular Malaysia
Figure 2 : Rainfall Map for Sabah and Sarawak