Tuesday, February 23, 2016

Hopes Rise if El Nino Eases: 
( Continuation from..We have probably reached the peak...published on 28th January).

" In Meteorological terms, this El Nino is now in decline. But we cannot lower our guard, as it still quite strong and in humanitarian and economic terms, its impacts will continue for many months to come." ..WMO Secratary General Petterri Taalas.
A very straightforward and cautious statement. 

The El Nino is surely on the wane. What we normally should observe initially is the Sea temperatures "below the surface'. If this lower "below sea level" waters start cooling, the cooler waters surface, and the sea surface temperatures drop in the wake of this process. Now, cooling sea water below surface are measured in the Eastern Pacific region.
However, Equatorial Pacific sea surface temperature anomalies (difference from normal) have cooled over the past fortnight. Actual temperature drop in Nino 3.4c is only 0.1c and 
in Nino 3 it is 0.2c.

Since its the anomaly that has dropped, the El Nino levels remain at moderate to strong El Niño levels. So, the virtual disappearance of this El Nino phenomena is still a long time away. April /May/ June may see a transitional Neutral Stage of the ENSO.

In the January period, we generally see a variation and intra-seasonal variability in the atmosphere (wind and pressure). This directly affects the  the Madden-Julian Oscillation (MJO) and OLR parameters. negative anomalies have been observed over the central and/or eastern Pacific.
Anomalous upper-level (200-hPa) easterlies were observed over most of the equatorial Pacific. Anomalous anti-cyclones straddled the equator. 

SOI values cannot be considered as reliable during this ( January) period. Seasonal storm systems cause massive fluctuation, from -23 on 26th Jan.. to -9 on 14th February.

The ONI is based on SST departures from average in the Niño 3.4 region, and is important in monitoring and even forecasting the expected turn of the ENSO event.
Most recent ONI value is 2.3. ( +0.5 and over is El Nino; -0.5 and below indicates La Nina. But for a full fledged La Nina (or El Nino), it must be consistent for at least 5 overlapping seasons. So, a La Nina developing before August does not look possible.

Australian Bureau of Meteorology:- "Based on the 26 El Niño events since 1900, around 50% have been followed by a neutral year, and 40% have been followed by La Niña. International climate models suggest neutral is most likely for the second half of the year. However, La Niña in 2016 cannot be ruled out."

Vagaries would estimate, as stated earlier in its article, the El Nino effect on the Indian climate would wane and decline only after June 2016. This would mean a weak sluggish start to the South West Monsoon. The Monsoon gaining strength after July is possible, and may extend into October. 
This would augur well for India, and would come as a relief after 2 consecutive drought years.

But, while determining the quantum of the 2016 Monsoon, we must understand and remember that ENSO is only 1 of the parameters. The IMD has 6 parameters to consider while giving its April forecast for the SWM. Gowarikar's method (still held in high esteem by Vagaries) has 16 parameters.

Next Part end of March.....

11 comments:

emkay said...

So far so good, we have to keep fingers crossed. Pray SWM doesn't suffer this time

Nilay Wankawala said...

Wonderfully presented as always sir....

rohit aroskar said...

Nice follow-up article Sir

Anuj Arora said...

Some good news even our winter rains were very poor due to this strong el Nino,will it affect the pre monsoon showers too and the western disturbances?

Atul Naik said...

Thanks for the detailed analysis and your precise conclusions.

abizer Kachwala said...

rajesh sir,will it rain in mumbai and north knokan in march and feb-ending?

rajesh said...

abizer: Will put up in weekend estimate on Thursday night.

Vijay Anand said...

Very hot summer in bangalore. Started quite early.
21-Feb 34.5
22-Feb 35.6
23-Feb 34.2
24-Feb 33.4

Never seen 35 degrees in Feb. Quite shocking.

Vijay Anand said...

HOT SUMMER STARTS IN BANGALORE QUITE EARLY:
DETAILS LISTED BELOW:

21-Feb 34.5
22-Feb 35.6
23-Feb 34.2
24-Feb 33.4

Cumulus Arjun said...

As El Niño is declining, the 2016 South West Monsoon of India is going to be good. June will be deficit, July will be near normal, August will be good and September too will be good.

Cumulus Arjun said...

As El Niño declines, the Indian monsoon 2016 will be good. June will be deficit, July will be near normal, August is going to be good and September too is going to be good.