During the period from August 1-10, 2005, the African portion of the Intertropical Convergence Zone was located near 19.0 degrees north latitude, compared to the long term mean position of 18.5N, and the previous dekad's location of 18.1N. Though the next dekad normally signifies the peak northward position of the ITCZ, that corresponding latitude was reached roughly four dekads ago. This is not to say that the 2005 seasonal ITCZ reached its northward peak four dekads ago, since the current dekadal location is the furthest north of the season to date. In the west (from 10W-10E), the ITCZ was located near 19.6N during the current period, compared to a long term mean of 19.4N and a position last dekad of 18.5N. In the east (from 20-35E), the ITCZ was located near 18.6N, compared to a long term mean of 17.2N and a position last dekad of 18.0N. All in all, it is yet undetermined if the ITCZ has reached its northward peak for the 2005 season.
Now the latest has come out and it looks like the eastern portion of the ITCZ in Africa has peaked in it's northward progress.. Normal but a FAR cry from the 1995 postion and duration we experienced during that busy season..
What a ride for the western region of the African ITCZ during the period from August 11-20 2005! Though Figure 2 shows a near constant latitude, compared to the previous dekad, of the region averaged from 10 degrees west to 10 degrees east, this is highly misleading due to the fact that the position is averaged for the ten day period. The fact is, that two strong Easterly Waves passed thru the region beginning on August 14th, brought rainfall to much of western Africa, and caused a very large daily fluctuation in the ITCZ. For example, the ITCZ near 5 degrees west longitude fluctuated from nearly 28 degrees north on August 16th to around 18 degrees north on August 17th. Strong northerly winds accompanied this movement, with dry air plunging southward to southern Burkina on the 16th. For the record, the ITCZ was located near 18.8N during the dekad, compared to a normal position of around 18.7N, and a position last dekad of 19.0N. Judging on the latest analysis, it appears that the ITCZ has reached its maximum northerly peak, at least in the eastern areas of Africa, though it is yet to be determined if such is the case in the west.
http://www.cpc.noaa.gov/products/fews/ITCZ/itcz.html
This should be an interesting second half of the season..
Paul
