Tropical Storm Rosa formed off the southwest coast of Mexico early in the day on 09 November 2006. In spite of existing in an environment of moderate southwesterly vertical shear, the tropical disturbance was able to intensify and exhibit bursts of convection which were evident on a QuickTime animation of GOES-13 10.7µm IR images (above). The cloud top temperatures were quite cold in these convective bursts, reaching -93 C at 12:15 UTC.

One thing to note on the GOES-13 IR imagery is the improvement in detector-to-detector “striping” (below) when compared to the previous generation of GOES satellites (GOES-11 and GOES-12) — this is due to better IR detector calibration on GOES-13.

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Japan’s deadliest tornado on record struck the town of Saroma (near the northern coast of the island of Hokkaido) around 04:00 UTC (1 PM local time) on 07 November 2006 (CNN news report). QuickTime animations of MTSAT-1R visible channel (above) and 10.7µm IR channel images (below) did not show any typical severe convection signatures such as an “enhanced-v” signature, but these images were only available at 30 minute intervals. Widespread convection was developing over that region in advance of an approaching mid-latitude cyclone that was rapidly intensifying — water vapor channel imagery (QuickTime animation) indicated that the upper level flow was strongly divergent over Hokkaido island, creating an environment favorable to supporting upward vertical motions and subsequent convective development.

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A QuickTime animation of GOES-11 visible channel images (above) revealed multiple plumes of glacial sediment blowing offshore along the coast of Alaska on 06 November 2006. Strong chinook winds in the glacial valleys were lofting dust and carrying it out over the adjacent Gulf of Alaska. This phenomenon had been occurring on other days in early November (as seen on a MODIS true color image 5 days earlier).

A longer (14-hour) animation using the GOES-11 10.7µm – 12.0µm IR difference product (below) shows a subtle blowing dust signal that can be followed during the non-daylight hours as well (when visible channel imagery is not available). The airborne particulate matter associated with the largest dust plume reduced the surface visibility to 2-3 miles at Cordova, Alaska (station identifier PACV) late in the day; also, note the rapid rise in temperature farther to the east at Yakutat, Alaska (station identifier PAYA), as easterly chinook winds arrived and gusted to 18 mph at 20:00 UTC.

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Two interesting semi-linear cloud features were apparent in the vicinity of the Hawaiian Islands on 06 November: (1) a cloud line to the lee of the Big Island of Hawaii, due to easterly “trade winds” within the marine boundary layer converging after flowing around the island (also note the small cyclonic eddy that formed immediately northwest of the Big Island), and (2) a long, narrow “rope cloud” that stretched for a considerable distance across the Pacific Ocean (to the north and northwest of Hawaii), which marked the leading edge of a cold frontal boundary which had become quasi-stationary (large-scale GOES-11 visible image animation).

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