Neutral ENSO conditions continue to prevail in the Pacific Ocean. Since mid-July most indicators of ENSO have remained close to normal. There are currently no precursors present for a La Niña or El Niño event to develop, and neutral conditions likely to persist through October 2011.
In a weak MJO period (lower above), expecting a system from our seas would be futile, and rare.
The current UAC over Gujarat, long having outlived its capacity, will show signs of waning from the 3rd/4th.
The current Bay UAC will have to decide its course of progress in the next few days. If it moves in by Tuesday/Wednesday, some heavy rainfall is possible for a day (as the UAC is not well established) in Vidarbh and adjoining South-east M.P.
But, as discussed many a times previously, in such a lean MJO phase, the monsoon axis could possibly move north of its normal position.
This could lead to good rains in the U.P. Gangatic plains, Bihar and in Nepal. Heavy rains in central Nepal and Bihar could be possible in the first half of August.
W.Ds are not really effected as such by a weak MJO, and if any W.D. inter-acts ( in the first half of August) with the north bound axis, heavy rains could be a possibility in Kashmir/H.P. Utterakhand and Northern Pakistan.
Rainfall in the central peninsula states (M.P./Gujarat/interior Mah/interior Karnataka) could get weaker, and the west coast rainfall would taper down considerably. South Interior peninsula not expected to revive meaningfully till mid-August.
Southern Pakistan rainfall can get scanty, as it would be bereft of any rain bearing systems, or trough precipitations.
Come Monday, 1st day of August, and the rains slowed down in Mumbai. Cloudy with a few showers, Monday saw 12 mms at Colaba and 5 mms at S'Cruz rain in the day, and the trend will continue into Tuesday/Wednesday. Rain amounting to around 15-20 mms/day.
Its just about possible, that there could be an nominal increase in rains on Thursday night. Say to around 30-35 mms.(Tentative).
Today, to give a forecast Friday onwards, i say a notable decrease in precipitation. Shall observe and review in a few days.
In Mumbai, July measured an average rainfall of 1285 mms between the 2 stations.Vagaries had estimated 800 mms.
Thanks for your views and analysis NT. Normal seasonal rainfall for Colaba has been reduced to 1920 mms From 2146 mms, and S'Cruz normal is 2422mms (2460 mms). July normal is 460 mms at Colaba and 553 mms for S'Cruz.
Looking at the above scenario, for Mumbai, I would expect rainfall to get a bit substantial in the 2nd fortnight of August. I could go wrong, but on the above 50-50 basis for the 2 halves of the month, I would estimate around 575-600 mms average between the 2 stations.