Further Analysis of the parameters as discussed in MW-1.
Let me explain, that the winds on crossing the equator break into 2 branches. i) gushing into the Arabian Sea, and ii) moving into the Bay of Bengal.
ii) In the eastern sector, in the Bay Branch, the Cross equatorial winds are perfectly diverted and change direction towards SW after just crossing the Equator. Thunder cloud (Cb) developments are seen near the region South of the Equator.
We prefer the Bay Branch to be better organised, as the SW Monsoon is normally expected there in 22-25 days…
Mascarene high pressure zones in the South Indian Ocean. Main High reading now 1024 mb and another one at 1023mb has been observed between Madagascar and Australia.
Indicator : normal
2. Seasonal Low:
The current temperature anomaly. Most of India is in the 4-7c above normal range and pockets shooting to 15 c above normal ...
Earlier than normal,the night temperatures have also crossed the 30c mark ! Barmer in Rajasthan recorded 30.4c as minimum on 15th April ,Kurnool (Andhra) saw a low of 31 c on 19th morning and Jhansi (UP) saw a low of 31.6 c on 21st morning.
But, in 2011, 2012, 2013 and 2014, till date, temperatures were yet to reach 45c anywhere in the Sub-Continent .
2015...Into the 3rd. week of April , we had seen 48c in Pakistan on 19th April in Larkana,and 46.5c in Moen Jo Daro. In India had just topped 44.6c in Barmer on 19th April.
2016....touched 46c in Bankura on 16th April...and was constantly hot in Eastern region with almost daily ,a place touching 46c.. Bhubaneshwar and Titlagarh in India and Dadu in Pakistan had touched 46c. Several large regions in Vidharbh, Telengana and MP were in the 44/43c range.
The seasonal Low, as a result of good heating, is shaping up fast. It has shown good progress after MW 1 when it was 1008 mb.
Last 2 days, the lowest pressure, in the core (Thar Desert) region was at 998/1000 mb. (In 2011/2014 was 1006 mb, 2010/2012 was at 1002 mb this time. 2015/2016 it was at 1000-1002 mb).
As mentioned, it normally should reach a low nadir of 994 mb in June in the Thar Desert, and with 1008mb in the South Arabian Sea, a perfect gradient is created to attract the south -west winds towards the coast.
Thunderstorm activity in Southern Tibet is seen to be picking up.
This enhances the speed of the Seasonal Low formation. Normally is required to start taking shape for the monsoon by the second week of April.
3. ENSO: This year also, like last year, we also base our observations on the Multivariate ENSO Index (MEI). An attempt is made to monitor ENSO by basing the Multivariate ENSO Index (MEI) on the six main observed variables over the tropical Pacific.
These six variables are: sea-level pressure (P), zonal (U) and meridional (V) components of the surface wind, sea surface temperature (S), surface air temperature (A), and total cloudiness fraction of the sky (C). (Negative values of the MEI represent the cold ENSO phase, a.k.a.La Niña, while positive MEI values represent the warm ENSO phase (El Niño).The MEI is computed separately for each of twelve sliding bi-monthly seasons (Dec/Jan, Jan/Feb,..., Nov/Dec).
Negative values of the MEI represent the cold ENSO phase, a.k.a.La Niña, while positive MEI values represent the warm ENSO phase (El Niño).
The updated (Feb-Mar) MEI is at -0.08 (in Jan-Feb was -0.056), for a slightly decreased ranking.
30 day SOI has fallen, and is now at -3.1 ( SOI of -7 to 7 is neutral. Above 7 is La Nina, and below -7 is El Nino ).
4. The Bay has hosted a pre monsoon low during mid April.
As discussed, we should normally see a low sometime after the 15th of April. The high pressure region in the Bay, at sea level, no longer prevails.
A strong MJO would hasten the favourable formations and lows, with enhanced precipitation. But the MJO, it seems will remain stalled (without eastward propagation) for the next 10 days .
Hence, not much progress is expected on this front during the next 10 days.
We prefer the Bay parameters to show progress faster , as the SW Monsoon is expected there in 22-25 days…
5. To bring the existing SE winds above the equator (as SW), the ITCZ should move northwards. Around 1st. of May, this should cross the equator. The ITCZ should now come back to its Northward position, as the effective "Lows" created by the Rossby Wave are reducing.
ITCZ is just south of the equator (1 s).
Parameter: 1) Normal 2) Normal 3) Neutral 4) -ve 5) Normal.
Summary : One parameter is -ve as of today . Parameters have improved compared to MW 1 .
We will put up the estimated date of arrival in the MW-3.
But, situations can change fast, and by the time we discuss the next MW, some factors can suddenly become +ve or -ve. So, MW discusses and follows the developments as they emerge, and discuss the parameters as is where is.
No model can commit today when the Monsoon can arrive.
Quantum of rain forecasting in April for June right through September is an impossible task. Things get clearer by last week of April. Vagaries' (in MW) normally remains true to estimates around early May.
Next MW up on 2nd May with Dates of Monsoon Arrival.