General Weather Situation over the Lower Mekong Basin (LMB)
17 September 2013
General Condition:
On September 17 2013 at 01.00 am Local Cambodia Time (LCT), the latitude from 00N to 280N
and the longitude from 900E to 1250E, the Inter Tropical Convergence Zone (ITCZ) lies across
the Central of Myanmar, the North and the Northeast of Thailand, the upper South of Lao PDR
and Central of Viet Nam connected to the Tropical Depression (TD) over the South China Sea,
centered about 450 kilometers East of Da Nang, Viet Nam at the latitude 16.50N and
longitude112.50E, the TD is moving Westward slowly with the maximum sustain wind about 55
km/h (Figure 1).
During September 17-19, the TD will upgrade as Tropical Storm (TS). The TS is expected to
move to the Central of Viet Nam on 19 September. Scattered thundershowers with isolated heavy
rain will be most likely in many areas in the South and the Southeast of Myanmar, the Central,
the Northeast and the East of Thailand, the Central and the South of Lao PDR, the Central and the
North of Viet Nam, the Southwest, the North and the Northeast and the East of Cambodia during
17-19 September.
The wind waves are expected about 1.5-2.5 meters high in the Andaman Sea and about 1.0-1.5
meters high in the Gulf of Thailand during 17-19 September 2013.
Figure 1: Weather Chart issued at 18:00 UTC on 16 September, 2013
Source: Thai Meteorological Department
Figure 2 of September 17 2013 at 06:30 am Local Cambodia Time (LCT) shows IR image which
is observed cloudy with the form of Cirrostratus (Cs), Altostratus (As), Altocumulus (Ac) and
Stratocumulus (Sc) and Cumulonimbus (Cb) overs the Central of Viet Nam and the Middle South
China Sea.
Figure 2: Infrared Image, MTSAT IR, at 23.00 UTC on September 16, 2013
Source: Japan Meteorological Agency
The active trough of low pressure lies across Myanmar, Thailand, Lao PDR, Cambodia and Viet
Nam. The Southwesterly wind prevails over Myanmar, Thailand and Indochina Peninsular at
01.00 pm (LTC) on 17 September, 2013(Figure 3)
Figure 3: Upper Air Weather Chart 850 hPa (1500 m), issued at 18:00 UTC on September 16
2013
Source: Thai Meteorological Department
The below show interactive weather forecast maps are produced from computer models on
September, 17 2013.
During September 17-19 2013, rain will be likely in the South and the Southeast of Myanmar, the
West the Central, the Northeast and the East of Thailand, the Central and the South of Lao PDR,
the Central and the North of Viet Nam, the the Southwest, the North and the Northeast and the
East of Cambodia (Figure 4)
Figure 4: The prognosticative maps issued at 12:00 UTC on September 16, 2013 for 72hrs
forecast
Source: Hong Kong Observatory
Conclusion: Severe Weather Situation
The Inter Tropical Convergence Zone (ITCZ) lies across the Central of Myanmar, the North and
the Northeast of Thailand, the upper South of Lao PDR and Central of Viet Nam connected to the
Tropical Depression (TD) over the South China Sea, centered about 450 kilometers East of Da
Nang, Viet Nam at the latitude 16.50N and longitude112.50E, the TD is moving Westward slowly
with the maximum sustain wind about 55 km/h at the surface. The active trough of low pressure
system lies across Myanmar, The North of Thailand, Lao PDR and Viet Nam at the height of
1.5km (850 hPa).
On September 17-19 2013, the TD will upgrade as Tropical Storm (TS). The TS is expected to
move to the Central of Viet Nam on 19 September.
As the result of these phenomena, it will bring scattered thundershowers with isolated heavy
rain will be most likely in many areas in the South and the Southeast of Myanmar, the Central,
the Northeast and the East of Thailand, the Central and the South of Lao PDR, the Central
and the North of Viet Nam, the Southwest, the North and the Northeast and the East of
Cambodia during 17-19 September.
WARNING: From 19-22 September, heavy and very heavy rain with gust will be most likely in
the Central, the lower North of Viet Nam, the South of Lao PDR, the east of Thailand and the
Northeast of Cambodia. The People live in the above mentioned areas should be aware of
severe weather condition.
The wind waves are expected about 1.5-2.5 meters high in the Andaman Sea and about 1.0-1.5
meters high in the Gulf of Thailand during 17-19 September 2013.
Note: This bulletin is published by Department of Meteorology in collaboration with the MRC’s
Regional Flood Management and Mitigation Center, Phnom Penh City, Cambodia.