An unusual weather system is currently impacting large parts of India, Pakistan and Afghanistan, bringing widespread thunderstorms, gusty winds, rainfall and even hailstorms at a time when summer conditions typically begin to set in.
The ongoing event is being driven by an active western disturbance that has formed a nearly straight, linear low-pressure trough stretching about 1,000 kilometres—from Afghanistan, across Pakistan, and into India. This formation is considered atypical, as most western disturbances usually follow a curved path.
Western disturbances are generally extratropical systems originating near the Mediterranean region and are more common during winter months, when they bring snowfall and cold weather to northern India. However, this system stands out both for its timing in late March and its distinct structure.
Widespread weather activity across regions
The system is associated with an upper-air cyclonic circulation over northern Pakistan, which is leading to widespread thunderstorms and winds ranging between 40 and 80 kmph across northwest India. Isolated hailstorms and light-to-moderate rainfall or snowfall have also been reported.
Heavy to very heavy rainfall has already occurred in sub-Himalayan West Bengal and Sikkim, while southern states including Karnataka, Andhra Pradesh, Kerala and Tamil Nadu have received significant showers. Hailstorm activity has also been observed in multiple regions.
Meteorological conditions indicate that the western disturbance includes a trough in the middle and upper atmospheric levels. This is interacting with several low-level cyclonic circulations over regions such as north Madhya Pradesh, east Uttar Pradesh, west Rajasthan, Haryana, northeast Assam, coastal Andhra Pradesh, and parts of Tamil Nadu and Kerala, intensifying weather activity.
System likely to weaken, another disturbance ahead
The current disturbance is expected to remain active over the Western Himalayas and adjoining plains through Friday, after which its intensity is likely to decrease.
However, forecasts suggest that another weaker western disturbance may approach the region around March 22, potentially bringing further weather changes.
Moisture sources behind the system
The primary moisture feeding this system originates from evaporation over multiple water bodies, including the Mediterranean Sea, Caspian Sea, Black Sea, and the Persian Gulf.
As the system moves eastward, it gathers additional moisture from the Arabian Sea. This moisture is further enhanced due to orographic lifting along the Himalayas. Simultaneously, existing troughs and cyclonic features over regions such as Gujarat and the Mannar area are contributing to increased low-level convergence, leading to intensified rainfall and storm activity.
Delhi-NCR sees cooler conditions and rainfall
In Delhi-NCR, light-to-moderate rainfall accompanied by thunderstorms and winds of 30–50 kmph is expected to continue until Friday. Daytime temperatures are likely to remain between 25 and 28 degrees Celsius, which is below the seasonal average.
Why late-March disturbances are uncommon
Climatologically, western disturbances are most frequent between December and February, with India typically experiencing four to six such systems per month during winter.
By late March, their frequency usually declines sharply as the jet stream weakens and shifts northward. Historically, only one or two such systems occur during this period each year.
However, recent trends suggest a gradual extension of the western disturbance season into April. Experts attribute this to changes in atmospheric patterns, including stronger subtropical jet streams and broader climate variability.