Mumbai: Regardless of the monsoon having arrived over Mumbai and adjoining areas on June 11- its regular onset time, town has barely obtained any intense monsoon showers that are in any other case typical at the moment of the 12 months.
As of June 23, as per rainfall knowledge obtainable with the India Meteorological Division (IMD), town’s rainfall deficit for the month up to now stands at a major 47%.
Since June 1, the IMD’s climate station in Santacruz — taken as consultant of town — has obtained 179.8mm of rain, as towards the traditional 342.1mm.
Consultants and officers attributed these circumstances to the absence of low-pressure methods within the Bay of Bengal and a ‘weak’ offshore trough within the Arabian Sea, near the Konkan coast. When the offshore trough is robust, the moisture content material within the ambiance will increase, leading to extra cloud cowl and rainfall. Sturdy low-pressure methods within the Bay of Bengal then ‘pull’ this moisture from the ocean and deposit it over the Konkan area, and play an necessary function in sustaining the energy of offshore troughs.
“Ideally, 12 low-pressure methods are anticipated to type within the 4 months of the southwest monsoon season, so you’d get 3 methods in every month (ie one each 10 days or so). When these methods type, and if they’re robust, they pull the monsoon winds over the Arabian Sea, which strengthens the offshore trough. Sturdy low-pressure methods would possibly even journey to western India, inflicting direct rainfall over Mumbai-MMR. In such a scenario, their presence may set off small vortices over the Arabian Sea close to Mumbai, inflicting continuous rain for a day or two that’s usually heavy. We have not seen any low-pressure system or this motion up to now,” identified Akshay Deoras, an impartial meteorologist and researcher on the College of Studying, UK, who intently tracks the southwest monsoon.
These low-pressure methods are usually not forming as a result of meteorological circumstances over the Bay of Bengal are usually not favorable for a similar at current. “Our analysis has proven that the tropical intra-seasonal oscillations, together with the Madden–Julian Oscillation (MJO), and the Boreal Summer season Intraseasonal Oscillation (BSISO), modulates the formation of those low-pressure methods. However at the moment, there is no such thing as a help by the MJO and BSISO since they don’t seem to be lively over the Bay of Bengal. In consequence, the monsoon winds over complete Maharashtra are weak at current,” Deoras added.
MJO is a band of rain clouds that strikes eastwards over the tropics and is chargeable for most climate variations within the area – together with the southwest and northeast monsoons. BSISO, one of many dominant phenomena over the Asian summer time monsoon area, is characterised by northward/northeastward propagation over the Indian summer time monsoon area.
Different consultants agreed with this evaluation. “There have not been any low-pressure methods throughout the Bay of Bengal this monsoon that would have favored lively monsoon circumstances alongside the Konkan coast, notably in Mumbai. There are three to 4 episodes of extreme rainfall forecasted for the area between June and September, however it’s troublesome to foretell when they’ll happen in the intervening time,” stated Mahesh Palawat, vice-president (meteorology and local weather change) at Skymet Climate, a personal forecaster.
An official with the IMD’s regional forecasting middle in Mumbai, nonetheless, stated that town is prone to see intense downpours on June 25 and 26. “Although there is no such thing as a low-pressure system within the east, there may be an higher air cyclonic circulation forming over the Arabian Sea attributable to which a number of elements of the Maharashtra coast will obtain intense showers. Nevertheless, the depth will quickly scale back after June 26,” the official stated.
