Operational weather forecasting using data from Automatic Weather Stations and other modern observing systems - Case study of tropical cyclone Jal 2010
Authors: AMUDHA B. , RAJ Y.E.A. 
Published: May 2022

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The hourly meteorological data available from hitherto unrepresented locations due to the installation of satellite-based Automatic Weather Stations (AWS) by India Meteorological Department are valuable. The potential utility of data from such AWS for operational weather forecasting is tremendous, particularly during adverse weather situations like that of a cyclonic storm. In this paper, a case study of the Tropical Cyclone (TC) Jal which formed during the period 4-8 November, 2010 over Bay of Bengal and crossed north of Chennai has been undertaken mainly by utilising data from AWS in the southern Indian peninsula. Utility of the data in assessment of the intensity of Jal has been explained. The landfall location of Jal near Sriharikota (SHR) around 1800 UTC of 7th November, 2010 could be pinpointed using wind and hourly pressure data correlated with inputs from other modern equipments like the High Wind Speed Recorder, products from Doppler Weather Radar (DWR) at Chennai and high resolution imageries from Kalpana-1 satellite. The pressure defect and maximum winds in the cyclone field have been computed by using a theoretically derived proportionality constant (K). An analysis on the effect of environmental flow, direction of movement and friction on the maximum winds observed in a land station has been made using the wind speed values recorded by AWS at Ennore Port located north of Chennai. The possible lower bound of wind speed of the cyclone while out at sea has been computed and verified that the operational declaration of the TC Jal as a cyclonic storm at 0600 UTC of 7th was correct.