Cyclonic whirl to spearhead weather over Northeast

Vinson Kurian



Thiruvananthapuram, Feb 26 :  India Meteorological Department (IMD) has confirmed the presence of a cyclonic circulation embedded into a trough as northwesterlies dipped into east and north-east India.
These atmospheric features will combine to preside over the unsettled weather that is forecast to evolve in the region over the next four to five days.

The trough should have normally showed up upstream over the northwest, but has presumably been thwarted by a ‘weather guard’ system in transition to being contra-indicative in that region.


YIELDING PLACE A reigning semi-permanent trough (low pressure) is in the process of yielding the seasonal perch to a semi-permanent ridge (high pressure).

This would mean that the prevailing hesitant rain/snow regime over the hills of northwest India would change over to being colder and drier climes.

The evolving ridge will force part of the northwesterly winds to divert from their usual path and bypass Jammu and Kashmir before being made to dip as a trough over east and north-east India.

The European Centre for Medium-range Weather Forecasting is of the view that the trough would hold strong until Sunday before weakening a bit. But strong northwesterly winds would continue to prevail over the Indo-Gangetic farther ahead.

WESTERLY SYSTEM According to the IMD, the trough in transition across the northwest border would still be able to engineer the passage of a weak western disturbance into the western Himalayas (Jammu and Kashmir and adjoining region) around March 2.

This would rule out any noticeable downward trend in the mercury levels in the northwest from the weekend as was inferred earlier. The minimum temperatures are above normal by 4 to 6 degree Celsius over west and adjoining central and east India.

Scattered to fairly widespread rain or thundershowers are expected over parts of the North-East States during the next four to five days.

In the South, a trough of low pressure over South Andaman Sea and adjoining southeast Bay of Bengal persisted on Wednesday. A cyclonic circulation lay over south Tamil Nadu and adjoining Kerala.

The Climate Prediction Centre of the US National Weather Services sees convection activity picking over equatorial Indian Ocean just south of Sri Lanka during the first week of March.

Meteorologists are watching if this could ‘excite’ a part of the Pacific convergence zone to the north to swing it over Sri Lanka and extreme south peninsular India and bring some welcome wet weather into the region.