MAPUSA
Despite an early onset on May 25 and a promising start, the southwest monsoon in Goa has recorded a 1.3 per cent rainfall deficit by the end of July, marking one of the weakest performances in recent years.
Weather experts attribute this shortfall to a combination of unfavourable synoptic conditions and atmospheric anomalies that disrupted typical rainfall patterns across the State.
The season began on an encouraging note, with widespread and fairly equitable rainfall during the first fortnight of June.
However, the momentum soon waned. As July progressed – typically the peak monsoon month – rainfall began to diminish, with long spells of dry weather and bright sunshine, unusual for this time of year.
Dr M R Ramesh Kumar, a noted meteorologist, explained the causes behind the weakening monsoon.
“Rainfall started decreasing from July 26 onwards due to multiple factors. The Monsoon Trough and the Off-Shore Trough from Kerala to Gujarat coast remained weak. The Low-Level Jet Stream, which plays a crucial role in monsoon intensity, was also subdued,” he said.
He added that a lack of convective systems – storm-like formations that drive rainfall – in both the Arabian Sea and Bay of Bengal contributed to the break in monsoon conditions.
“Only four convective systems formed over the Bay of Bengal in July, all short-lived. These are critical to sustaining rainfall across the subcontinent and their absence was felt across Goa as well,” he said.
Another major factor was the dominance of northwesterly and northerly upper-level winds (between 1,000 to 3,000 meters altitude), which brought in dry air masses instead of moisture-laden winds from the ocean.
“These dry winds suppress cloud formation and can even lead to temperature inversion over the Arabian Sea, further reducing rainfall,” Dr Kumar explained.
The impact of these weak systems is reflected in the rainfall data.
Only four stations in Goa – Sanquelim, Dharbandora, Quepem and Sanguem –recorded over 2,000 mm of rainfall.
Dharbandora registered the highest total at approximately 2,744 mm, while Mormugao recorded the lowest with just 1,303.9 mm – less than half of the Dharbandora total.
“This shows the wide intra-state variability in rainfall,” said Dr Kumar, pointing to the uneven distribution that has marked this year’s monsoon in Goa.
What is particularly worrying, he added, is that July and August typically account for around 61 percent of Goa’s average seasonal rainfall.
A significant drop during this period could impact groundwater recharge, agriculture, and reservoir levels going forward.
Last year, by contrast, July saw one of the highest rainfall totals in over 125 years, making this year’s performance stand out for all the wrong reasons.
With August underway and monsoon conditions still subdued, all eyes are on weather systems in the Bay of Bengal and Arabian Sea to see whether Goa’s rains can recover in the weeks ahead.
