Kant et al. (2025) Case study on exceptionally heavy rainfall episode over Northwest Uttar Pradesh & adjoining Uttarakhand (India) during Monsoon 2024

Identification

• Journal: Bulletin of Atmospheric Science and Technology
• Year: 2025
• Date: 2025-12-01
• Authors: Shashi Kant, Rizwan Ahmed, Naveen Kumar, Ram Singh Yadav, Rohit Thapliyal, R. K. Jenamani
• DOI: 10.1007/s42865-025-00115-z

Research Groups

• India Meteorological Department, Ministry of Earth Sciences, Mausam Bhavan, New Delhi, Delhi, India
• Regional Meteorological Centre, India Meteorological Department, Ministry of Earth Sciences, Nagpur, Maharashtra, India
• Meteorological Centre, India Meteorological Department, Ministry of Earth Sciences, Dehradun, Uttarakhand, India

Short Summary

This study analyzes an exceptionally heavy rainfall event over Northwest Uttar Pradesh and Uttarakhand in July 2024, detailing its complex meteorological causes, associated impacts, and the effective performance of India Meteorological Department's forecasts, while also evaluating various reanalysis precipitation products.

Objective

• To analyze the meteorological setting, associated impacts, and the performance of forecasts and warnings issued by the India Meteorological Department (IMD) for an exceptionally heavy rainfall event over Northwest Uttar Pradesh and Uttarakhand during 7–8 July 2024.

Study Configuration

• Spatial Scale: Northwest Uttar Pradesh and adjoining Uttarakhand, India (specifically districts like Bareilly, Champawat, Udham Singh Nagar).
• Temporal Scale: The exceptionally heavy rainfall event occurred on 7–8 July 2024, with meteorological analysis and warning assessments spanning July 4–8, 2024.

Methodology and Data

• Models used:
  • Fifth-Generation European Centre for Medium-Range Weather Forecasts Atmospheric Reanalysis (ERA5)
  • Indian Monsoon Data Assimilation and Analysis reanalysis (IMDAA)
• Data sources:
  • Manual observatories (India Meteorological Department - IMD) for rainfall.
  • Satellite observations: INSAT-3D/3DR (IR1 blended imagery, Hydro Estimator Precipitation (HEM) maps, Improved Multispectral Rainfall Algorithm (IMSRA)).
  • Reanalysis/Satellite-Gauge datasets: ERA5 (0.25° × 0.25° resolution), IMDAA (0.12° × 0.12° resolution), Daily Merged Satellite–Gauge Rainfall (GPM) product (0.25° × 0.25° resolution), Integrated Multi-satellite Retrievals for Global Precipitation Measurement (IMERG) (0.1° × 0.1° resolution).
  • Synoptic information: All India Weather Bulletins (AIWB), Weekly Weather Reports, and press releases from IMD.
  • Wind data: 3-hourly 10 m wind data from synoptic stations (Palam, Safdarjung, Bareilly, Pantnagar).
  • Impact data: Situation reports from the Ministry of Home Affairs.
  • Dynamic conditions: Meteosat 9 (for upper-level divergence, lower-level convergence, wind shear, relative vorticity).
  • Upper air observations: University of Wyoming (for thermodynamic parameters like CAPE, Showalter index, Lifted Index, Total Precipitable Water).

Main Results

• Exceptionally heavy rainfall (ExHR) occurred on 7–8 July 2024, with 24-hour accumulations exceeding 400 mm at some stations (e.g., Baheri: 461 mm; Banbasa: 431 mm).
• The event impacted approximately 34,730 people across 53 villages in three districts of Uttar Pradesh and caused one landslide, two flash floods, and damage to 63 houses in Uttarakhand.
• Key meteorological conditions included an upper-air cyclonic circulation over southwest Uttar Pradesh and adjoining northeast Rajasthan, an upper air trough extending to the northeast Arabian Sea, and interaction between mid-tropospheric westerlies (Western Disturbance) and low-level monsoonal easterlies.
• The monsoon trough was in a near-normal position from July 4–7, supporting deep convection, and shifted southward on July 8, correlating with a reduction in rainfall intensity.
• Satellite observations (INSAT-3D/3DR) revealed intense convective activity, cloud-top temperatures below -80 °C, and precipitation rates exceeding 30 mm/h, indicating deep convective systems and orographic lifting.
• Among the evaluated reanalysis/satellite-gauge datasets, the Daily Merged Satellite–Gauge Rainfall (GPM) product provided the most accurate rainfall estimates compared to ground observations, while IMERG, ERA5, and IMDAA generally underestimated intensity and/or misrepresented spatial distribution.
• The India Meteorological Department (IMD) successfully anticipated the event, issuing quantitative precipitation forecasts and impact-based warnings with a lead time of three to five days (e.g., Red warnings for extremely heavy rainfall issued three days in advance for Uttarakhand). Skill scores for heavy rainfall warnings were high (Probability of Detection (POD) of 0.8–0.9 for West Uttar Pradesh and Uttarakhand).

Contributions

• Provides the first scientific investigation and detailed documentation of the specific exceptionally heavy rainfall event over Northwest Uttar Pradesh and Uttarakhand during July 7–8, 2024.
• Offers a comprehensive analysis of the complex interplay of synoptic and mesoscale meteorological systems responsible for the extreme rainfall, including cyclonic circulation, Western Disturbance interaction, and monsoon trough dynamics.
• Conducts a critical assessment of various reanalysis and satellite-gauge precipitation datasets (GPM, IMERG, ERA5, IMDAA) against ground observations, identifying the most reliable product for this region and event.
• Evaluates the performance of the India Meteorological Department's early warning system, demonstrating its effectiveness in anticipating and communicating severe weather threats.
• Underscores the vital role of satellite data (INSAT-3D/3DR) in real-time monitoring, understanding, and operational forecasting of extreme rainfall events in monsoon-prone regions.
• Contributes to a better understanding of the favorable environmental conditions for exceptionally heavy rainfall events in Northwest Uttar Pradesh and adjoining Uttarakhand during the monsoon season.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Citation

@article{Kant2025Case,
  author = {Kant, Shashi and Ahmed, Rizwan and Kumar, Naveen and Yadav, Ram Singh and Thapliyal, Rohit and Jenamani, R. K.},
  title = {Case study on exceptionally heavy rainfall episode over Northwest Uttar Pradesh & adjoining Uttarakhand (India) during Monsoon 2024},
  journal = {Bulletin of Atmospheric Science and Technology},
  year = {2025},
  doi = {10.1007/s42865-025-00115-z},
  url = {https://doi.org/10.1007/s42865-025-00115-z}
}