Significant Improvement in Rainfall Forecast over Delhi: Annual and Seasonal Verification

Kuldeep Srivastava (Scientist & Head, Regional Weather Forecasting Center (RWFC), India Meteorological Department, New Delhi, India)

Article ID: 4769



Regional Weather Forecasting Centre (RWFC) New Delhi has the responsibility to issue and disseminate rainfall forecast for Delhi. So it is very important to scientifically verify the rainfall forecast issued by RWFC. In this study rainfall forecast verification of Delhi has been carried out annually and season wise for the period 2011 to 2021. Various statistical parameters such as Percentage Correct (PC), Probability of Detection (POD), Missing Ratio (MR), False Alarm Ratio (FAR), Critical Success Index (CSI), True Skill Statistics (TSS) and Heidke Skill Score (HSS) have been calculated for season wise and annually. A forecast is considered to be improved if PC, POD, CSI, TSS and HSS increase and FAR and MR decrease over a period of time. The author can conclude that annual accuracy of forecast has increased significantly over the period of time from 2011 to 2021, as PC, POD, CSI, TSS and HSS increase and FAR and MR decrease over a period of time. Maximum contribution in the improved forecast has observed in transition season (pre-monsoon season followed by post-monsoon, having rainfall activity mainly in association with thunderstorms), when FAR and MR have decreased drastically.


Thunderstorms; Percentage correct; Probability of detection; Missing ratio; False alarm ratio; Critical success index; True skill statistics; Heidke skill score

Full Text:



[1] Casati, B., Wilson, L.J., Stephenson, D.B., et al., 2008. Forecast verification: current status and future directions. Meteorological Applications. 15(1), 3-18. DOI:

[2] Mason, S.J., 2008. Understanding forecast verification statistics. Meteorological Applications. 15(1), 31-40. DOI:

[3] Nurmi, P., 2003. Recommendations on the verification of local weather forecasts. DOI:

[4] Murphy, A.H., 1993. What is a good forecast? An essay on the nature of goodness in weather forecasting. Weather and Forecasting. 8(2), 281-293. DOI:;2

[5] Hitchens, N. M., Brooks, H. E., Kay, M. P. , 2013. Objective limits on forecasting skill of rare events. Weather and forecasting, 28(2), 525-534. DOI:

[6] Srivastava, K., Nigam, A., 2020. Rainfall estimation using image processing and regression model on DWR rainfall product for Delhi-NCR region. Journal of Atmospheric Science Research. 3 (1), 9-15. DOI:

[7] Doswell, C. A. III, Davies-Jones, R., and Keller, D. L., 1990. On summary measures of skill in rare event forecasting based on contingency tables. Weather and Forecasting. 5(4), 576–585.


  • There are currently no refbacks.
Copyright © 2022 Author(s)

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.