Assessment of extreme rainfall events over northwest India in the second week of July 2023

Mishra, K., Kant, S., Hunt, K. ORCID: https://orcid.org/0000-0003-1480-3755 and Kumar, V. (2025) Assessment of extreme rainfall events over northwest India in the second week of July 2023. Meteorology and Atmospheric Physics. ISSN 1436-5065 (In Press)

Abstract/Summary

Extremely heavy rainfall (> 20 cm per day) occurred across Northwest India (NWI) from 7th to 11th July 2023, leading to substantial loss to public property & life. This event was one of the most severe in recent history, with significant impacts across the whole of NWI, especially in Himachal Pradesh, the most affected state. Numerous stations across the region set new daily and seasonal all-time high rainfall records during this event. The weather event, spanning from 7th to 10th July, was characterized by the formation of a Low Pressure Area (LPA) over southwest Rajasthan on the 9th, which moved northeastward. The associated cyclonic circulation extended up to 700 hPa, with the monsoon trough extending from the LPA towards Northeast India. A deep western disturbance (WD) trough was present in the middle tropospheric levels between 500 hPa and 400 hPa with a southward extension into the Arabian Sea. Notable features of this event include a significant drop of 2-4 hPa in mean sea level pressure over Northwest India on 9th July with deep moist southwesterlies impacting NWI. The eastern end of the monsoon trough initially received moisture from the Bay of Bengal (BoB) but ceased this influx on 9th July as the trough moved northward. As a result, moisture was only transported from the Arabian Sea, leading to intense rainfall over NWI. The interaction between the WD, southwesterlies from the Arabian Sea, BoB easterlies peaked during the 9th and 10th July although the moisture transport from the BoB remained lesser after 8th July. The WD trough remained quasi-stationary along at around 66°E from 7th to 10th July, likely influenced by strong anticyclonic systems on either side, contributing to the sustained weather conditions. This unusual atmospheric setup led to widespread record-breaking rainfall over NWI.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/127323
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Springer Verlag
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