ThiruvananthapuramMarch 7The two incoming western disturbances are now expected to hit northwest India back-to-back, with the latter of the two being a `particularly strong' one.
The India Meteorological Department (IMD) has confirmed this in its forecast on Wednesday. This effectively rules out the usual `window' for cold air advection that separates two successive western disturbances by margins ranging from four to five days.
One-plus-one need not necessarily imply two, but could jump several scales to translate as 11, depending on the relative strengths of the systems and the conditions under which they operate locally. Rising temperatures in March and incoming moisture make for an explosive mix for the plains with adverse implications for standing crops.
Rabi wheat outlook
Sources in the Government who did not want to be named said that the outlook on rabi wheat issued on Wednesday might not possibly have factored in the double whammy from the westerlies prospectively from Friday. The Ministry of Agriculture bases its forecasts on the feedback supplied to it the preceding week only.
The European Centre for Medium-Range Weather Forecasts has maintained its outlook for unsettled weather peaking to a high along a north-south alignment along the 30 deg North Latitude on March 13. Punjab, Haryana, East Rajasthan and even Delhi fall within its footprint.
This is more or less in agreement with IMD's outlook, which says that two western disturbances will hit the region in quick succession during March 8-11 and March 11-13. It cites numerical weather prediction models to declare that the latter one would likely be the more active. March 13 could just happen to be the median date for the two systems to operate at their howling best and set off heavy rain, high winds and hail. According to Dr K.J. Ramesh of the Department of Science and Technology, only time and circumstances will tell how these pan out. There is a case for exercising vigil given the threat to standing crops. Dr Ramesh attributed the evolving bad weather to a semi-permanent trough that has been persisting over South Pakistan and adjoining West Rajasthan over the past four weeks. Even the flimsiest westerly `pulse' travelling to the east becomes amplified several fold on passing this massive resident feature. This is what has been driving western disturbances one after the other across the border into northwest India, he added.