Actinoform Clouds (Actinae) in the Eastern Pacific Ocean

March 13th, 2007 |

GOES-11 visible image

GOES-11 visible channel (daytime) and 3.9 µm shortwave IR (nighttime) imagery revealed an interesting cyclonic vortex which was propagating westward across the eastern North Pacific Ocean on 13-14 March 2007 (Java animation | QuickTime animation). The radial banded cloud features that form such a cloud “swirl” are known as actinae or actinoform clouds, and they are seen occasionally in the marine stratocumulus cloud field over the Pacific Ocean (one such case was June 1997). This type of cloud pattern was first observed back in 1962 on TIROS V imagery near Hawaii.

Fog in Florida Causes Multiple Vehicle Accident

March 13th, 2007 |

AWIPS images of MODIS and GOES fog product

Thick fog forming in southern portions of Osceola county in Florida was a factor in causing a multiple vehicle accident along the Florida Turnpike during the morning of 13 March 2007. AWIPS images of the MODIS and GOES fog/stratus product several hours before the accident (above) shows how the 1-km resolution MODIS product had better skill at depicting the location and coverage of the fog (compared to the 4-km resolution GOES product).

Smoke from small brush fires in that area on the previous day was thought to have helped to further reduce surface visibilities along with the fog; an AWIPS image of the GOES-12 3.9µm IR channel (below) shows a “hot spot” (red enhancement) associated with a fire that was burning just west of the Florida Turnpike in central Osceola county at 21:31 UTC on 12 March. The GOES-12 3.9µm brightness temperature at that particular hot pixel was +40º C; however, most of the brush fires in that area were apparently too small in size to produce similar hot spots at other image times, and the CIMSS Wildfire ABBA product only indicated a few brief fire pixels in central Florida during the day on 12 March.
AWIPS image of GOES 3.9µm IR