Posted by Mike Doran on 3/5/2009, 4:26 pm, in reply to "Cyclone Hamish Forms off Northeast Australian Coast"

SOI flattened out a bit and is at real near zero for two days in a row. My view on that is the tropical entity becomes the low impedence event in the region and there isn't enough displacement currents to cause the extreme low or high pressures in EITHER the west of the east. Remember the SOI is a relative pressure measure of two data points--Tahiti and Darwin, and this storm essentially sits inbetween those locations, even though it is obviously closer to Darwin. But both locations are connected by the warm tropical Pacific ocean, and this is warm, highly conductive salt water. I think such a strong, coupling organization electrically impairs any extremes of pressure in EITHER region and hence the SOI stays near zero. What that THEN means is that there are no significant pulses of potential difference globally that impact something occurring locally, so there isn't going to be a falling SOI impact for severe weather for the next couple of days with this storm doing what it is doing.