India being mainly an agricultural country the economy and further its growth purely depends on the vagaries of the weather and in particular the extreme weather events. The information on extreme weather events lie scattered in the scientific and technical papers and in the research work of many authors and if put together will help the research community for further analysis.

Tropical cyclones—variously defined as hurricanes, typhoons, and cyclones—regularly impact human populations and periodically produce devastating weather-related natural disasters. The epidemiology of tropical cyclones is fundamentally determined by the physical forces of massive cyclonic systems intersecting with patterns of human behavior. The destructive forces of cyclonic winds, inundating rains, and storm surge are frequently accompanied by floods, tornadoes, and landslides.

Two cases of intense western disturbances which affected the northwest India have been investigated using the India Meteorological Department’s operational limited area analysis and forecast system. The model results are compared with the synoptic observations, which have been enriched by additional stations installed under the national project ‘Parwat’. The analysis shows that the 24-hour model forecasts are in good agreement with the observations both in respect of western disturbance’s movement and intensification.

An empirical model for predicting the maximum surface wind speed associated with a tropical cyclone after crossing the east coast of India is described. The model parameters are determined from the database of 19 cyclones. The model is based upon the assumption that tropical cyclone winds decay exponentially after landfall.

Original Source

Rainfall and maximum and minimum temperature data of 32 years (1970-2001) at Semiliguda, Koraput (Orissa) were analysed to study the weekly, monthly and yearly drought investigation by studying the water balance. The IMD method was adjusted more suitable for drought identification than the revised IMD method.

About 80 tropical cyclones (with wind speeds equal to or greater than 35 knots) form in the world’s waters every year. Of these about 6.5% develop in the Bay of Bengal and Arabian Sea. Since the frequency of cyclones in the Bay of Bengal is about 5 to 6 times the frequency of those in the Arabian Sea, the Bay of Bengal's share comes out to be about 5.5%. The tropical cyclones forming in the Bay of Bengal hit the coast of India (particularly the states of Andhra Pradesh, Orissa and West Bengal) every year, causing heavy loss of life and property.

In the past decade there has been extensive research into tropical intraseasonal variability, one of the major components of the low frequency variability of the general atmospheric circulation. This paper briefly reviews the state-of-the-art in this research area: the nature of the Madden-Julian Oscillation, its relation to monsoonal and extratropical circulations, and the current theoretical understandings.

Original Source

Statistics relating to the date of onset of the southwest monsoon over Kerala for the 100-year period 1891-1990 reveal that the mean and median dates of onset for south Kerala are 31 May and 1 June, with a standard deviation of 8.5 days. Declaring the date of monsoon onset is not a straightforward matter. However, rainfall pattern, uppper air circulation features and INSAT cloud pictures are useful guides, and these indicate that the onset date in 1990 esd 17-18 May. During 1891-1990 there have been onlyy 12 years in which the date of onset over Kerala has been on or before 18 May.

A research paper by Gowariker have used multiple and power regression involving 15 independent variables for long range forecasting of monsoon rainfall in India. They have also argued that, when most of the independent variables are 'favourable' almost invariably the monsoon rainfall is normal. In this note we formalize this approach using a parsimonious logistic regression model. The probability of a normal rainfall can be assessed in most cases using only five of the 15 variables.

Records of hemispheric average temperatures from land regions for the past 100 years provide crucial input to the debate over global warming.