Persistent fog and stratus over southern California

September 8th, 2010 |
MODIS fog/stratus product + GOES-11 fog/stratus product

MODIS fog/stratus product + GOES-11 fog/stratus product

AWIPS images of the 1-km resolution MODIS fog/stratus product and the 4-km resolution GOES-11 fog/stratus product (above) revealed the presence of fog and stratus clouds that extended fairly far inland across much of southern California around 06 UTC on 08 September 2010 (11 pm local time on 07 September). The improvement in spatial resolution on the MODIS image allowed a more accurate assessment of the location of the stratus cloud edges, as well as the location of the cloud holes immediately offshore.

McIDAS images of the GOES-15 0.63 µm visible channel data (below) showed how persistent this deck of stratus clouds was during the daytime hours. In fact, these clouds held down temperatures such that the daily high temperature was only 68º F at Burbank (station identifier KBUR, located near the center of the images) — their normal high temperature for the date is 88º F, and they had a high temperature of 102º F just 4 days earlier.

GOES-15 0.63 µm visible channel images

GOES-15 0.63 µm visible channel images

10-km resolution GOES-11 sounder Cloud Top Height product images (below) showed that there was a high amount of variability in the heights of these stratus cloud tops (which was also evident in the appearance of the stratus cloud deck on the GOES-15 visible imagery above).

GOES-11 sounder Cloud Top Height product

GOES-11 sounder Cloud Top Height product

Igor forms in the far eastern Atlantic

September 8th, 2010 |

Tropical Storm Igor has formed in the far eastern Atlantic, just south of the Cape Verde Islands. GOES-12 imagery from today (above) shows a sheared system with persistent and abundant convection southwest of a low-level swirl of clouds. (That low-level swirl is most evident in the 1145 UTC image). Igor formed just north of a region of significant shear (shown here) and the shear may slow intensification of the storm.

Other environmental factors favor strengthening. For example, MIMIC total precipitable water (from this website) shows abundant moisture surrounding the developing storm. An analysis of the Saharan Air Layer shows little signal in the region of the storm. Igor’s forecast path is over warm water. Forecasts from the National Hurricane Center suggest slow strengthening as the system moves westward across the tropical Atlantic.

For more information on Igor, visit the CIMSS Tropical Weather Website and the National Hurricane Center Website.

(Added: Click here for views centered on Igor from GOES-12, GOES-13 and GOES-15, satellites over the Equator at 60 W, 75 W and 89 W, respectively)