La Nina weakens but may rebound by year-end, say Japanese scientists

Latest forecast update from Japanese scientists have said that the La Nina signal in the east equatorial Pacific has weakened rapidly in March.

The La Nina, which caused excessively wet and flooding events in many parts of the world during the last year, would decay further in the following months.

The Tokyo-based Regional Institute for Global Change (RIGC) under the Japan Agency for Marine-Earth Science and Technology (Jamstec) has also maintained a ‘normal-to-slightly above normal’ forecast for the Indian monsoon this year.

Like last year, parts of east-central India and northeast India are, however, expected to witness below-normal precipitation.

The condition may not get as severe, according to Dr Jing-Jia Luo, Senior Scientist at the Regional Institute for Global Change (RIGC), under the Japanese Agency for Marine-Sciences and Technology (Jamstec). The decaying La Nina could later show a ‘Modoki’ (Japanese for ‘similar, but different’) pattern.

But Dr Jing sought to maintain the RIGC forecast for a cold La Nina condition to rebound later this year and persist up to early 2012.

A weak negative Indian Ocean Dipole (IOD) pattern with positive sea surface temperature anomalies in the eastern equatorial Indian Ocean may occur alongside, which is considered prejudicial to an Indian monsoon.

The RIGC also said that the flooding conditions in Australia, northern Brazil and southern Africa, in line with the fortunes of the La Nina, might weaken in the following summer but might return in the fall.

Dry conditions would emerge over the stretch from southeastern China to south Japan during March to June, followed by above-normal precipitation in June and hot-dry condition in July.

Meanwhile, back home, the western disturbance over Jammu and Kashmir and neighbourhood is moving eastwards, an India Meteorological Department (IMD) said this (Wednesday) morning. The induced upper air cyclonic circulation over Haryana lies over northwest Uttar Pradesh in lower levels.

A trough from this system extends southwards up to south Tamil Nadu across west Madhya Pradesh, interior Maharashtra and interior Karnataka in lower levels. The upper air cyclonic circulation over Nagaland and neighbourhood also persists in lower levels.

Satellite imagery in the morning showed the presence of convective (rain-producing) clouds over parts of east Uttar Pradesh, west Bihar, west Assam, north Chhattisgarh, south Arabian Sea, Lakshadweep area and north Andaman Sea.

A fresh western disturbance would affect northwest India from Friday onwards. A weather warning said that isolated thunder squalls would occur over east Uttar Pradesh, Bihar, Jharkhand, east Madhya Pradesh, Vidarbha, Chhattisgarh, Orissa and West Bengal and Sikkim until Friday.

A short-term forecast said that scattered rain or snowfall would occur over Uttarakhand and isolated over Jammu and Kashmir and Himachal Pradesh until Thursday. However, rain or snowfall activity would increase later.

Fairly widespread rain or thundershowers would occur over the sub-Himalayan West Bengal, Sikkim and the Northeastern States. It would be scattered over east Uttar Pradesh, east India and Maharashtra, Goa and isolated over central India.

Isolated rain or thundershowers would occur over Rajasthan and west Uttar Pradesh. Scattered rain or thundershowers would occur over Karnataka, Kerala, Lakshadweep, Andaman and Nicobar Islands and isolated over north Andhra Pradesh and Tamil Nadu.

Maximum temperatures would rise by 2 to 3 deg Celsius over northwest and central India today and tomorrow.

An extended outlook until Saturday said that scattered rain or thundershowers would occur over the Northeastern States. Scattered rain or thundershowers would occur over east and adjoining central India, Kerala and coastal Karnataka.

COMMENT NOW