5th August 2004: 12UTC
We have used the air mass RGB to help identify the key features and to enable us to identify tropopause differences as well as the warm and cool air sources associated with the development of Alex.
In the air mass RGB (channels 6.2-7.3,9.7-10.8,6.2i), dry descending stratospheric air related to an advection jet appears in a reddish colour.
Warm air mass with high tropopause appear in a greenish colour and cold air mass in a blueish colour.
5th August 2004: 15UTC
We have used the air mass RGB to help identify the key features and to enable us to identify tropopause differences as well as the warm and cool air sources associated with the development of Alex.
In the air mass RGB (channels 6.2-7.3,9.7-10.8,6.2i), dry descending stratospheric air related to an advection jet appears in a reddish colour.
Warm air mass with high tropopause appear in a greenish colour and cold air mass in a blueish colour.
5th August 2004: 18UTC
We have used the air mass RGB to help identify the key features and to enable us to identify tropopause differences as well as the warm and cool air sources associated with the development of Alex.
In the air mass RGB (channels 6.2-7.3,9.7-10.8,6.2i), dry descending stratospheric air related to an advection jet appears in a reddish colour.
Warm air mass with high tropopause appear in a greenish colour and cold air mass in a blueish colour.
5th August 2004: 21UTC
In these images we can clearly see the dry stratospheric air to the north of the Tropical cyclone associated with the polar front jet and in the top right corner of the image the weak frontal band. To the south of the depression there is a further jet evident, which is the sub tropical jet. Alex is clearly seen in the center of the image with a large cirrus shield.
6th August 2004: 00UTC
In these images we can clearly see the dry stratospheric air to the north of the Tropical cyclone associated with the polar front jet and in the top right corner of the image the weak frontal band. To the south of the depression there is a further jet evident, which is the sub tropical jet. Alex is clearly seen in the center of the image with a large cirrus shield.
6th August 2004: 03UTC
In these images we can clearly see the dry stratospheric air to the north of the Tropical cyclone associated with the polar front jet and in the top right corner of the image the weak frontal band. To the south of the depression there is a further jet evident, which is the sub tropical jet. Alex is clearly seen in the center of the image with a large cirrus shield.
6th August 2004: 06UTC
There appears to be some warmer air to the east and southeast of the hurricane at low levels indicated by the greenish cloud on right of the frame. This area is coincident with the warm tropical air which has been drawn northwards as the hurricane has moved east over the Atlantic.
6th August 2004: 09UTC
We can now observe that the cirrus shield is eroding and appears detached from the lower level cloudiness. The low level cloud shield appears green in colour. This area is associated with the low level, high dew point air. The upper cirrus shield begins to move southwestwards with the lower level high dew point air moves northwards towards to Polar jet.
6th August 2004: 12UTC
In this final image the cirrus shields continues to move southwest as the lower level high humidity air moves closer to the jet. At this time all the elements are in present for explosive deepening to take place.
Upper level trough, associated with the pre-existing weak system to the north.
