The Hindu Business Line : New Year may bring rains to the North

Cold to severe cold conditions have enveloped much of north, northwest, east and central India even as these regions extended their wait for the first meaningful winter showers.

But things may change with the dawn of the New Year, with the long-awaited and suitably ‘endowed’ western disturbance forecast to cross the northwest border to herald the much needed rains.

WESTERLIES FLAIL

According to indications available, the ‘biggie’ western disturbance could canter into the country around January 5. The sufficient magnitude would help it get around the semi-permanent ‘ridge’ located somewhere over Pakistan and yank it off its stubborn anchor at least for sometime to come.

Seasonal ‘western disturbances’ bring rain to the north and northwest India, but they seem to have bypassed the region by straying to a predominantly north-northeast direction thus, far during this winter.

Only those with enough magnitude to dip to more southerly latitudes can bring wet weather to these areas known for their substantive holdings of crucial rain-fed Rabi crops.

These ideally choreographed western disturbances have been conspicuous by their absence, until now. This is being attributed to the presence of the increasingly frequent semi-permanent ridge formation. The ridge deflects the India-bound western disturbances from their chosen path.

This is not for the first time that this anomalous ridge (high-pressure area) has prevented western disturbances from dumping snow and moisture, respectively, over the high reaches and plains of northwest India. But, at no time, in the recent past has this rogue system been able to stay anchored for this long and in such hardnosed fashion.

INDUCED LOW’S

Weathermen also point to the virtual absence of induced low-pressure systems that get embedded into the westerly trough which have in the past heralded widespread rainfall in the north and northwest.

These low’s absorb moisture wafting in from the Arabian Sea to the southwest and in turn dump the same over a much wider swath along the plains in the north and northwest.

The prevailing weather draws a parallel with that marking the corresponding period last year, when December had ended up virtually dry. The rains had broken out in the following February only.

FORECASTS MIXED

The European Centre for Medium Range Weather Forecasting (ECMWF) has forecast normal rainfall for most of the northwest, except west Rajasthan, for January-February-March.

But the UK Met Office has predicted dry weather for the region with cold or average cold conditions prevailing more likely during the period. The International Research Institute (IRI) for Climate Prediction and Society at the University of Columbia has put most of west Rajasthan, Gujarat and western India under ‘dry season masking.’ The rest of the region may have normal rainfall.

CONTRASTING SCENARIO

This contrasts with the scenario emerging to the South thanks to a resurgent La Nina in the equatorial Pacific.

The IRI has forecast that forcing of tropical moisture from the east (west Pacific, South China Sea) might help douse the impending summer in the peninsula with some unseasonally heavy showers.

Computer models continue to indicate the persistence of cold east Pacific temperatures, consistent with a La Nina, until about April or May 2008, said an Australian Bureau of Meteorology (BoM) forecast.

There must be five consecutive, overlapping three-month seasons, to be considered a full fledged La Nina or El Nino. “So far for this current La Nina we are up to three, but it is just a matter of time,” reasons AccuWeather.com.