Chase For Intense-Monsoon starts-Conditions Gearing up
-By Sai praneeth
The South-Indian wait??
For the past 2 years, there was a drought-like condition in many parts of country. Inspit of very-heavy rainfall over coastal Tamilnadu and South-coastal Andhra pradesh, drought prevailed over rest of south-india. During 2014-elnino like conditions prevailed and the monsoon systems didn't materialize over india.
We have seen cyclone Komen over Sunderbans last year, which caused a good rainfall in july. But monsoon failed to make its promise during august and September.
2014-Elnino-like conditions
2015-Elnino conditions
During 2014,2015 there were severe conditions, which didn't supplied enough energy to the indian ocean, to trigger an intense monsoonal system.
Hud-Hud Matter??
Cyclone Hud-hud was an exceptional case, it evolved due to the superimposition of rossiby wave and MJO pulse. The MJO and Rossiby wave are the energy banks which containes heat in trapped form and propogates from one place to another. Rossiby travels from east to west and MJO travels from west to east. Some times they meet a point and cause a heavy system irrespective of elnino/lanina.
This Time Monsoon Hit/Miss???
To see this, we have to take main factors like-
ENSO-(ELNINO SOUTHERN OSCILLATION)
Its the matter of pacific and the latent heat stored in the pacific ocean constitutes the changes in the walker circulation. The walker circulation is the sole responsible of seasonal variations of climate and weather. For the sake of brevity, the NOAA divided pacific into 4 divisions. (Nino 1+2,3,3.4,4)
elnino-conditions |
Lanina-conditions |
Latest conditions:
Nino-3-
Nino-3.4-
Nino-4-
Inference-
So, by the end of august, there will be lanina like conditions and the amplitude of south-west monsoonal rainfall concentrates form second-week of august to the end of september. I am expecting a post-monsoon low-pressure to touch the shores of andhra pradesh around october 1st week, as per latest CFS trend.
july- Average rainfall expected
August-Above Normal rainfall expected
September-Above Normal rainfall expected
Madden Julian Oscillation-
Madden julain oscillation is a main constituent future of Rainfall pattern over India. Even in a massive elnino year, there will be some rains over india which is a consequence of Madden julian oscillation. I say it as a gift for monsoonal countries like India, Australia. During Lanina years, more latent heat is transferred to indian ocean and when MJO superimposes with the Sea surface temperatures(Latent heat).
It works on the principle of law of conservation of energy. "Energy can neither be created nor be destroyed but it can be changed from one form to another form". Over a period of 30-90 days, it suppresses the rainfall for some period and gives heavy rainfall or even monsoon systems over a period of time. It will dissipate, when it touches the central portion of pacific. Again, the energy is gathered in the form of latent heat over africa and the pulse with trapped energy, propogates east-wards.
Latest-Conditions-
Inference--
Recently MJO pulse became zero in magnitude and negligible Gain-margin. Now again, the energy is gathering near the east coast of somalia and the amplitude of MJO likely to increase by june.
Quasi-Bennial Oscillation-
Its the upper air directional effect. It influences the Monsoonal flow and the strength of monsoon currents. The clouds develop well if the QBO resultant wind direction and Monsoonal direction are same.
INFERENCE-
It is seen that the Monsoon will be good, if the QBO vector points to westwards, supporting the monsoonal flow at lower-levels. QBO vector is taken at 30-70hPa levels from Base ground (1133hPa).
Latest Observation-(Fight of Mean surface level pressure with a Low in indian ocean)
INFERENCE-
Due to a low persisting over southern indian ocean, the cross equatorial currents are unable to set. The low is expected to clear off by 2-3 days and conditions of Monsoon will be back to normal.