Howdy,

Tony Cristaldi (NWS Florida)  has annotated a nice image of the twin vortices in the Indian Ocean, with the new/second pair forming west of the Malay Peninsula.  It is on his web-page at http://home.cfl.rr.com/tcrist/images/MJO.jpg; and I have also put it on my web page under today's date.

Mark Lander
TC group,

    The MJO continues its journey to the east through the Indian Ocean and
perhaps on over to the western Pacific next week (see Matt Wheeler's
Equatorial modes web page:
http://www.bom.gov.au/bmrc/clfor/cfstaff/matw/maproom/OLR_modes/index.html).
(Current Matt Wheeler/Boy-wonder Hovmoller)
    I'd like to use the attached Fig. to take a swipe at recent ideas
concerning the reason for an observed preference for genesis at the
eastern end of the monsoon trough.  Several authors have suggested that
the eastern end of the trough is a priveleged site for genesis because it
is a collection zone for wave energy moving in from the east.  In the
attached Figure, one can see the existing twin TCs in the western Indian
Ocean, and what appears to be the next two in line for development at the
eastern side of that basin.  The new genesis is certainly at the eastern
end of the monsoon, but does TC genesis here have a need to accumulate
wave energy from points east?  It would seem that the genesis privilege
granted to the vortex at the eastern end of the trough is an artifact of
the eastward moving MJO, and the generation of TC twins by local
excitation of the N=1 Rossby wave mode.

    Regards,  Mark Lander
 

John McBride

Yes, it is an interesting situation.  The easternmost/developing pair has a really nice satellite signature now and there is a well-defined northern hemisphere vortex in the 850 hPa wind field at about 95E, just north of Sumatra (see my web page).

As I discussed a couple of days ago (when Mark Williams first noticed this eastern pair), they showed up initially as a pair of upper level anticyclones.  These have increased in scale and have drifted apart, so that the more coherent equatorial Rossby wave feature now seems to be at the lower levels. (The current 250 hPa chart is also on my web-page).

The low level Darwin chart shows a nice westerly jet in the eastern Indian Ocean as per Mark (L)'s schematic.  However there is not much of a feature westerly burst/jet feature at all on today's CDC NOAA tropical analysis at http://www.cdc.noaa.gov/map/images/fnl/sfcwnd_01b.fnl.html (reproduced on  my web-page) The CDC page also has a sfc wind anomaly chart for the last seven days; but that also has the westerly anomaly in the western Indian Ocean and not in the eastern Indian Ocean.

Unfortunately the Darwin real-time charts cut out at 70E.  Does anyone out there know of a web-page showing good realtime flow charts of the tropical Indian Ocean?  They would be useful for us to be able to follow the Indian monsoon and evolution of TC's and monsoon depressiosn in discussion fora such as this.

cheers

John McB