El-Nino Still Holding Grip on Monsoon Estimate:
Monsoon 2010 ! How is this year's Monsoon going to behave ? This unknown factor is of utmost importance today. 2009 was disastrous, (see Oct 7th. post in this link),with -23% rains, one of the lowest in Indian history. and we certainly cannot afford another scarce monsoon, leave alone a deficient one.
For guaging the initial development of the current of the ensuing monsoon, whether it will achieve the required momentum, at this stage today, we should primarily keep track on the El-Nino.
El-Nino strenght/Weakness will help us then chase and monitor the other parameters that develop subsequently in April/May.
March is the time of year when existing El-Nino events are often in their waning phase, and should either dissipate or persist for up to a maximum of two more months. This year, it seems most likely that El Niño conditions will persist at least through April 2010.
IRI forecasts-"Presently, the models and observations taken together indicate probabilities of about 85% for maintaining El Niño conditions and about 14% for dissipation to ENSO-neutral conditions for the Mar-Apr-May season in progress. Going forward, probabilities for El Niño decrease to approximately 50% by Apr-May-Jun."
Reason given by BoM:- Sea surface temperatures across the central tropical Pacific have shown little change over the past fortnight, and hence remain at levels typical of an El Niño event. Trade winds in the tropical Pacific have remained weak, allowing the Pacific to remain warm and hence slowing the decay of the El Niño event, and the SOI has also remained at El Niño levels.
The latest approximate 30-day value of the SOI is −8. The SOI has remained steady over the past week, after increasing in value after a rapid fall during February.
Another important factor are the trade winds.They are slightly weaker than normal across most of the tropical Pacific.
However, most international computer models are predicting a return to neutral conditions during the coming months.
Next update on El-Nino on 3rd.April.
More feedbacks and cross references always welcome on this crucial and important topic.