Bay watch

It shows an unsettled setting from the southeastern Arabian Sea and southern India to western Indonesia and the Malay Peninsula. Ill-defined cores seem to be near southern India and near Sumatra. The pattern of high cloud (whitest is coldest and thus highest) to the west suggests upper winds about a ridge, aloft, fanning these clouds westward and northward; the ridge would be anchored over eastern India. This radial flow could be supportive for the growth of a tropical depression in the area, most likely west of southern India, were it to persist.

Lowest pressure now has two centers: one is east of Sri Lanka and the other over the Laccadive Sea. I believe that the one to watch here is the western one, given what I am seeing on numerical weather forecasts. Make no mistake about it, though: there is not yet a consensus as to where and when any depression or cyclone would happen. Indeed, I do not see this as a `done deal` yet.

Latest numerical forecasts include the GFS, which is slow to grow a low over the Arabian Sea. It eventually (after November 5th) brings rain to southern Oman. It also suggests a southern Bay low, but the timing is different--later by 2-3 days--than had been earlier shown.

The NOGAPS has two lows developing including a Bay low that lands in SE India at about Oct 28. This is once again slower than earlier forecast runs. The NOGAPS has a stronger Arabean Sea low--further west and faster--than the GFS.

The ECMWF from earlier Tuesday shows a strong low (if true, it would be an important tropical cyclone) ominously near to southern Oman by October 30th. As for the Bay, the trend is in line with the other models: a low (depression or cyclone) that is shown to be slower to form than on earlier model runs.

It is still a waiting game without much confidence. The time of year is right for a depression or cyclone--and so is the overall weather setting. Yet it may take another few days to get a basic idea of where any such weather system, or systems, takes shape.