Looking at the recent equatorial sea surface temperatures (SST) records, it seemed that El Niño had started tapering down. However, the deadly phenomenon has once again bounced back.
After dropping consecutively for three weeks, SST in Nino index of 3.4, which is the area of concern for India, has increased again last week. However, despite drop, Nino indices were settling well above the threshold values throughout. Following are current values of various indices across the Pacific Ocean.
Not only this, the Oceanic Niño Index (ONI), which is three months running mean of SST anomaly in the Niño 3.4 region, also continues to be above the threshold values. The most recent ONI value AMJ (April – June) is 0.7°C.
The average value of Oceanic Niño Index (ONI) taken over a period of three months for the last eight consecutive episodes are as follows:
Looking at the continuous drop in SSTs, Australia’s nodal weather agency, Bureau of Meteorology (BOM) had withdrawn the El Niño watch and believed that indices would continue to remain below the threshold value. Unlike rest meteorological agencies across the world who consider 0.5°C as threshold value, BOM follows threshold value at 0.8°C. However, rest of agencies have not lowered the guard.
As per weather models, the probability of El Niño during July still continues to be as high as 70%-75%. In fact, the probability would continue to over 50% throughout the ongoing Monsoon season.
Impact on performance of Monsoon 2019
We have already seen the impact of El Niño over Monsoon season during June, which ended with huge rainfall deficiency of 33%. July did see Monsoon reviving during the first fortnight, but the country is now heading for break Monsoon conditions.
Usually, country witnesses break Monsoon condition in August as by then the Monsoon had covered entire India. Although, this has not been the case so far, but weather conditions are almost akin to what of which we witness during El Niño years.
During an El Niño, we expect more as well as prolonged spells of break Monsoon conditions. Although all the other factors favouring Monsoon such as MJO (Madden–Julian Oscillation) and IOD (Indian Ocean Dipole) are present, but as believed El Niño is the most powerful phenomenon and has the power to dominate all.
Image Credit: NDTV
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