Prepare for thundershowers: Met dept warns of rough start to monsoon in Mumbai

The city woke up to the third bout of strong pre-monsoon rains on Thursday. The India Meteorological Department (IMD) has issued a weather warning that forecasted ‘extremely heavy rain’ between Saturday and Monday (June 9 to June 11). This could mean there is a possibility of 200m or more rain during a 24-hour period.

While the city recorded no rainfall on Tuesday and Wednesday, gusty winds lashed the city from 3.30am on Thursday. Santacruz, representative of the suburbs, recorded 35.8mm between 3.30am and 8.30am on Thursday; Colaba (south Mumbai) recorded 18.8mm.

Under the weather department’s classification, 15.6mm to 64.4mm of rain is considered ‘moderate’, 64.5mm to 115.5mm is ‘heavy’, 115.6mm to 204.4mm is ‘very heavy’ and more than 204.5mm is ‘extreme’.

From 8.30am onward, intermittent showers were recorded across the city with a few spells of heavy rain. While Santacruz recorded 39mm rain, 27.6mm was recorded in Colaba between 8.30am and 5.30pm.

Due to overcast skies and intermittent rain, day temperatures at Colaba and Santacruz fell four degrees Celsius below normal. While Colaba recorded 29.5 degrees Celsius, 29.2 degrees Celsius was recorded at Santacruz. The night temperature at Colaba was 23.5 degrees Celsius (3.5 degree Celsius below normal), while 25.2 degrees Celsius was recorded at Santacruz (1.6 degree Celsius below normal).

Moisture levels were high, with 95% humidity at Colaba and 90% at Santacruz.

Mumbai suburbs have recorded 96.7mm rain since June 1, which is 55.9mm above normal for the period; and south Mumbai has recorded 50.6mm rain, 12mm above normal.

The weather bureau said these were still pre-monsoon showers but conditions were favourable for the southwest monsoon to set in over Maharashtra by Friday and over Mumbai by Saturday.

The southwest monsoon had made its landing over Goa on Thursday. The normal onset date for the southwest monsoon over Mumbai is June 10.

The warning issued on Thursday stated: “The widespread rainfall activity is likely to continue till June 10. It is very likely to extend to north coastal Maharashtra, including Mumbai from Friday. Extremely heavy rainfall at isolated places in these regions is also very likely during this period.”

The weather advisory issued for June 9 and 10 on Thursday read, “As rainfall activity is likely to enhance from June 9 with further increase on June 9, people are advised to abstain from outdoor activities as much as possible during the period and also watch for weather updates from Regional Meteorological Centre, Mumbai.”

KS Hosalikar, deputy director general western region India Meteorological Department, said, “Apart from the monsoon current there is a weather system over central Maharashtra, which is being pulled closer to an offshore trough (another weather system) extending from south Konkan to north Kerala, allowing more moisture incursions over the west coast. During the confluence of these two weather systems, the heavy rainfall activity is expected.”

On Friday, the city could expect thundershowers accompanied by gusty winds at many places with very heavy rain likely at isolated places, read the IMD forecast.