English: Tropical Storm Igor has gone through cycles of strengthening and weakening over the last few days. Upper level winds and dust blowing off of Africa caused atmospheric shearing of the storm over the previous 24 hours, reducing Igor's intensity. Those winds have weakened today (Sept. 10, 2010) and the storm is intensifying once again. Shown here are two images taken by the GOES-East satellite, 24 hours apart (both at 0945z on Sept 9th and 10th, 2010) using both visible and infrared water vapor channels. In the colorized water vapor imagery, red-orange areas indicate dry air, whereas moist areas are indicated by blue colors. The dust blowing off of Africa can be seen in both the visible imagery as a faint cloud-like haze coming off the African coast, and as dry air in the water vapor imagery. Notice that in the recent imagery, the intensity of the dry air has lessened, and the storm's moisture has increased, along with the organized cyclone shape of intensifying tropical storms.