First organised pulses of 2026 south-west monsoon appear to be gathering with Myanmar pencilling in a near-normal onset even as twin low-pressure systems threaten to stir the Bay of Bengal into early-season action.
The monsoon may set in over southern Myanmar during May 13 to May 17, almost in line with the climatological date of May 18, before steadily advancing into the country’s deltaic regions between May 18 and May 22, according to the latest outlook issued by the Myanmar Department of Meteorology and Hydrology.
Twin systems seen
The Myanmar agency also hinted at an increasingly energetic Bay of Bengal during the next fortnight beginning Monday, with two low-pressure areas expected to form over the basin, one of them possibly intensifying into a depression. Such a sequence, it said, would support a monsoon of moderate strength during the period.
First ‘low’ forms
Closer home, the India Meteorological Department (IMD) on Monday morning confirmed the formation of a low-pressure area over the south-west Bay off the north Sri Lanka coast, and immediately placed it under watch for further intensification during the next two days.
Weather forecasters are closely tracking future course of the system, which could offer the first meaningful indication of how the larger monsoon circulation intends to organise itself over the region. Under normal May conditions, prevailing monsoonal flows tend to shepherd such systems east-north-eastwards, away from the Sri Lanka and Tamil Nadu coasts and into the central Bay on a path leading towards Myanmar and Bangladesh.
Pre-monsoon complexity
But the atmosphere may not yield so easily this time. Numerical weather models are yet to converge on the exact movement and evolution of the nascent system, reflecting complexity typical of the pre-monsoon transition phase .Complicating matters further is a supportive circulation in place over the south-east Arabian Sea and adjoining Lakshadweep off Kerala coast. The IMD has identified a cyclonic circulation there, linked to an elongated trough extending across Coastal and South Interior Karnataka into North Interior Karnataka.
Encouraging precursor
Meteorologists believe the interaction between the Bay system and this Arabian Sea circulation could prove decisive in determining whether the ‘low’ escapes into the open central Bay or remains tethered closer to the southern peninsula for longer than usual. This has injected fresh momentum into monsoon discussions, especially after weeks of intense pre-monsoon heating over the subcontinent. Any sustained organisation of low-pressure systems over the Bay at this stage is generally regarded as an encouraging precursor to seasonal rains, though forecasters caution that the atmosphere is still in its formative phase and prone to abrupt shifts.
Rain, thunderstorms
Even as the Bay begins to stir with early weather activity, widespread thunderstorm outbreaks and heavy rain are entrenching themselves across large parts of the peninsula and North-West India, signalling an increasingly volatile transition into the monsoon. Heavy overnight rain lashed isolated pockets of Tamil Nadu, Puducherry and Karaikal through Monday into the early hours of Tuesday, with the India Meteorological Department (IMD) warning that more intense spells are likely over the southern peninsula during the coming week.
Isolated heavy falls
The IMD has forecast isolated heavy rainfall over Tamil Nadu, Puducherry, Karaikal, Kerala and Mahe during the next six days as moisture-laden winds from both the Arabian Sea and Bay of Bengal wallop the region.
Scattered to fairly widespread thunderstorms accompanied by lightning and gusty winds with speeds of 30-50 km/hr are expected over Tamil Nadu, Puducherry and Karaikal on Tuesday; and Kerala and Mahe; Interior Karnataka; and Coastal Andhra Pradesh and Yanam over the next four days. Similar weather may prevail over Rayalaseema through Thursday, while Telangana and Lakshadweep are likely to witness thunderstorm activity during the immediate short term.
Help from seas
The IMD has also retained a watch for persistent thunderstorm activity over Tamil Nadu, Puducherry and Karaikal for three more days beginning Tuesday, while Coastal Karnataka may experience unstable weather conditions for at least four days. The broadening rain belt across the peninsula comes against the backdrop of the ‘low’ over the south-west Bay and an active cyclonic circulation over the south-east Arabian Sea near Lakshadweep, both of which are helping pump enormous quantities of moisture inland.
Western disturbance
Farther north, the atmosphere remains equally restless under the influence of a fresh western disturbance positioned as a trough along an alignment that links Multan in Pakistan and Ludhiana in Punjab. Supporting upper-air cyclonic circulations persist over West Madhya Pradesh and West Rajasthan, while an elongated trough stretches eastward across East Madhya Pradesh, Chhattisgarh and Jharkhand into the plains of northern West Bengal.
Volatile weather
These interacting systems are expected to trigger isolated to scattered light and moderate rainfall accompanied by thunderstorms, lightning and gusty winds reaching 30-60 km/hr across Punjab; and Haryana, Chandigarh and Delhi during the next four days. Rajasthan is likely to remain under the influence of the system through Wednesday, while West Uttar Pradesh may see thunderstorm activity on Tuesday and Wednesday, spreading into East Uttar Pradesh during Wednesday and Thursday.
In the western Himalayan region, weather conditions are expected to turn markedly turbulent. Scattered to fairly widespread rain and snowfall accompanied by thunderstorms, lightning and gusty winds of 40-60 km/hr are forecast over Jammu-Kashmir-Ladakh-Gilgit-Baltistan-Muzaffarabad during next three days; over Himachal Pradesh for five days; and Uttarakhand for four days.
Monsoon theatre
The IMD has also warned of isolated hailstorms over Jammu-Kashmir-Ladakh-Gilgit-Baltistan-Muzaffarabad through Tuesday, with Himachal Pradesh and Uttarakhand likely to witness hail activity during Wednesday and Thursday .Taken together, the simultaneous activation of Bay systems, Arabian Sea circulations and western disturbances points to a highly dynamic weather phase across the subcontinent. This could likely serve as a precursor to the larger seasonal reorganisation associated with the advancing south-west monsoon.
Published on May 11, 2026