Monday, May 04, 2015

Pre monsoon rainfall a precurser of SWM RF?

 The IO high pressure system lies at 90 Deg East. with core pressure a woofing 1036 hPa.
Winds liberated from this "high" will engulf south Indian peninsula from South to SW. That is the Power House of SWM is drifted towards EAST and the western planch lies exactly at 90 Deg East.

Usually whenever there is excess rainfall in pre monsoon period it can indirectly indicate below than NORMAL SWM rainfall for India.
This indicates that deficient rainfall for SWM 2015 as predicted by IMD.

Weather Instagram at May 04, 2015 at 06:37PM

6pm, Bhubaneswar - after a heavy electric shower another one approaching. #weather

from Instagram

May 04, 2015 at 06:47PM

RT @Venky1971: @weatherofindia Heavy to heavy Rain now with hail stones Hubballi / Hubli (Karnataka) 6pm. #iwm

Weather Instagram at May 04, 2015 at 06:03PM

5:30pm, Heavy rain in Pollachi, Tamilnadu. #weather

from Instagram

Weather Instagram at May 04, 2015 at 06:01PM

5:20pm, Heavy rain in Tumkur. #weather

from Instagram

Weather Instagram at May 04, 2015 at 05:59PM

5:11pm, Bangalore - a huge T cell seen over NW. #weather

from Instagram

Weather Instagram at May 04, 2015 at 05:57PM

4pm, its very dark in Bhubaneshwar. #weather

from Instagram

Weather Instagram at May 04, 2015 at 05:52PM

4pm, a T shower plodding thru plains near Dohnavur as seen from hills. #weather

from Instagram

May 04, 2015 at 03:39PM

2:55pm, Badlapur 39°C with 30% humidity. Hot. 😰 #iwm

May 04, 2015 at 03:38PM

42°C Now In Malout , Punjab. 2:54pm. #iwm

Weather Instagram at May 04, 2015 at 03:37PM

3:20pm, smashing rains In thiruvattar Marthandam belt in kanyakumari district. #weather

from Instagram

May 04, 2015 at 02:53PM

Chennai - 2:30pm, less hot today at 34C feels like 41.5 C. #iwm

Weather Instagram at May 04, 2015 at 02:17PM

10:45am, Naraikadu, S Tamilnadu... At 4800 ft above sea. #weather

from Instagram

South West Monsoon 2015 - update #1 - Parameters check

The feared "El Nino" - South West Monsoon killer is almost here !!
Further warming of the central Pacific ocean has created a right scenario for El Nino in next 1 or 2 months. This parameter is really not good for our important South West Monsoon.

Here's the latest, 29-Apr-2015, report from BOM-Australia ( ...

ENSO indicators in the tropical Pacific are approaching El Niño levels. Sea surface temperatures now exceed El Niño thresholds and trade winds have remained weaker than average for several weeks. This suggests some coupling between the ocean and atmosphere may be occurring. If these patterns persist or strengthen, El Niño will become established. Based upon model outlooks and current observations, the Bureau's ENSO Tracker is at ALERT status. This indicates that there is triple the normal chance of El Niño in 2015."
The Indian Ocean Dipole (IOD) ...

Climate models surveyed in the model outlooks favour a continuation of a neutral phase of the IOD over at least the next few months. Positive IOD events are more likely to occur in conjunction with El Niño, therefore climatologists will closely monitor the Indian Ocean for any early signs of a developing event. "

In fact, a positive IOD along with El Nino will actually counteract with the negative effect of the El Nino on SW Monsoon... click here for more on this

Central, N-W India Heat LOW

As of today, 3-May-2015, the LOW pressure generated by HEAT over N-W, Central, East India is around 1006mb and this is HIGH at this time of year. It should be around 1000 / 1002mb.
Heating has just started over N-W, central, East India after a long wet April due to strong W.Ds.

This heating is further expected to be disturbed by more W.Ds from 6-May to 12-May. .

Sea Surface Temperature(SST) over Bay and Arabian sea

SST over most of Bay is around or above 30 C, meanwhile there's almost NO reduction in SST seen along Somali seas, this is sign that less winds are reaching Somali coast from Mascarene HIGH pressure. Note, around 25-May, the SST along Somali coast should be around 20 C.


The expected Bay LOW during 2nd or 3rd week of April did not materialize and till now there's less signs of it. Today, a weak low-level circulation seen over S-W Bay and Srilanka, this is expected to persist and drift West into Gulf Mannar and S Tamilnadu during next 2 or 3 days. A Bay LOW is an important parameter before the onset of Monsoon winds into S,S-E Bay and S Andaman Islands.

Latest GFS run, suggests that Monsoon winds / Cross equatorial winds will reach S,S-E Bay by 16/17-May !

Mascarene HIGH pressure system and Cross Equatorial Winds

A good high pressure system with pressure up to 1028mb is seen over South Indian Ocean, slightly East to the expected position, and this is OK at this point of time.

As of now very less winds are reaching the Horn of Africa, this is expected to pickup around or after 10-May-2015.

Long Range Forecast by JAMSTEC

For your info, a Long range model of 24-Apr-2015 predicts a above normal rainfall for Kerala, Karnataka coast, Andaman Islands and East, E-central and N-E zones of India from June to August 2015.