Thursday, February 2, 2012

Role of ‘Nowcasting’ in Weather Forecasting

Exchange of information between people is not only a starting point for communication but also a valuable resource for different services. Weather forecasts are issued for various spatial and temporal domains to meet demands of different users.

Location specific forecasting of high impact weather events like severe rainstorms, sudden dense fog, severe heat and cold spells, severe thunder storms for a very short time range remain a challenge for the meteorological community worldwide.

When any high impact weather event strikes any metro city or any other urban and rural pockets affecting lives of common people severely, we wonder whether it could have been forecasted, at least a few hours, if not days, in advance, for public benefit.

It is common knowledge that manifestations of internal dynamics within a given boundary condition are extremely complex and vitiate the outcomes on the small spatial and temporal scale of extreme weather. Operational forecast procedures mostly fail to forecast exact timing and location of any high end weather event.

Further research on various tools used for issuing such forecasts e.g. empirical and NWP models and their ensembles, also have high limitation in predicting high variability at 12-24 hours time scales.

Modern observing and analytical systems now in place for use in real time operations are expected to improve the accuracies of monitoring and forecasting of high impact weather events. A technology driven system of 24X7 ‘Monitoring and Nowcasting’ is the need of hour.

It should be able to predict the time of start, minute by minute progression and final cessation of the event. Such a ‘Monitoring and Nowcast System’ will minimize the loss of invaluable lives and also property.

A number of Forecast Demonstration Projects (FDP) conducted in different parts around the world have demonstrated that the only way to improve the forecasting accuracies of  short period (0-6 hours) are by introducing monitoring strategies like developing a MESONET over the area, including a dense network of DWR coverage and high resolution satellite pictures/products etc.

In addition, very high resolution NWP and autonowcast systems would also be required as was done during Oklohoma Mesonet and Nowcast system, Beijing Olympic 2008 Forecast Demonstration Project and Delhi Nowcast for 2010 Commonwealth Games.

India Meteorological Department, Ministry of Earth Sciences (MoES), Government of India organized a Training Workshop cum National Seminar on Challenges, Developments and Opportunities in Nowcasting (CDO-NOW-2012) during 27-31 January 2012 at New Delhi.

The main aim of organizing this important event was to give a thrust for development and implementation of a 24x7 Monitoring and Nowcasting system in India especially with respect to high impact weather events.

The training program was designed to impart theoretical as well as practical aspects of Nowcasting to the trainees. The focussed discussion were held on monitoring of high impact weather events with the help of conventional and automatic observations, satellite information, Numerical Weather Prediction Models and Doppler Weather Radar products and synergising all the available input and techniques for issuing operational Nowcast.

The aim was to develop a sort of Standard Operating Procedure for issuing Nowcast of extreme weather events in mega cities in the first phase. About 20 resource persons were drawn from various departments. About 50 trainees were selected who are mainly involved in forecasting in various organizations and also research scholars. (Source: PIB.01.02.2012)

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