The 2007 tropical cyclone season has been rather boring quiet in both the Atlantic and East Pacific basins so far…but on 16 July 2007, Cosme became the first East Pacific hurricane of the season (about 1600 miles east-southeast of Hawaii). It is interesting to note that only 4 previous East Pacific tropical cyclone seasons have had their first hurricane form later than Cosme. An animation of GOES-11 visible imagery (above) showed some hints of an eye from 19:00-21:00 UTC, but subsequent convective bursts around the core of the storm masked the presence of an eye after that time. The CIMSS “TCTrak” analysis tool (below) indicated that Hurricane Cosme existed in an environment of relatively weak deep-layer (200-850 hPa) wind shear, which was a factor that aided in the slow intensification to hurricane strength during the day. The “TCTrak” tool is a feature on the newly-revised CIMSS Tropical Cyclones website that allows the user to select a variety of satellite views and meteorological product overlays.

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As much as we enjoy evangelizing satellite imagery and demonstrating all its useful applications, there are situations when satellite imagery simply is not as helpful as we would hope it might be. On 11 July 2007, a lightning strike started a fire at the Sunoco Oil Refinery near West Deptford, New Jersey (just south of Philadelphia, Pennsylvania, station identifier KPHL). An AWIPS image of the GOES-12 10.7µm IR channel with cloud-to-ground lightning strike data overlaid (above) was rather unremarkable in it’s presentation of the convection that was producing the lighting just prior to the time that the fire reportedly started. While there were some cloud top brightness temperatures as cold as -62º C (dark red enhancement) located a bit farther to the north between KPHL and KPNE, there was no other IR signature (such as an “enhanced-v”) that would suggest a severe convective potential; in fact, IR brightness temperatures in the area of the southernmost cluster of oil refinery lightning strikes were as “warm” as about -48º C (light green enhancement). In addition, the storm was producing just over 100 cloud to ground lightning strikes every 15 minutes, but that number is by no means extraordinary. Finally, cloud cover in the hours following the start of the fire prevented a “hot spot” from being detected on the GOES-12 3.9µm IR channel imagery.

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A GOES-12 imager “decontamination procedure” was performed on 02 July 2007, where certain internal optical components were heated in an attempt to drive off contaminants that had been accumulating for several years. One obvious problem associated with this internal contamination was a “rollover” of warm 3.9µm IR brightness temperatures, such that they were incorrectly displayed as very cold temperatures. This problem made it impossible to determine the hottest brightness temperatures associated with areas of intense fire activity (see recent examples from the Lake Tahoe, Lake Okeechobee, New Jersey, and Georgia fires).

Two sequences of daily GOES-12 3.9µm IR images show regions of sun glint off the Pacific coast of Mexico at 20:45 UTC (above), and also off the coast of Washington / British Columbia at 03:45 UTC (below). Prior to the decontamination procedure at 12:34 UTC on 02 July, portions of the sun glint that should have exhibited very warm IR brightness temperatures (black enhancement) were instead displayed as very cold areas (yellow enhancement); following the decontamination, the regions of daily sun glint were correctly displayed as having warm IR brightness temperatures, indicating that the procedure was successful.

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An AWIPS image of the MODIS sea surface temperature (SST) product on 06 July 2007 (above) showed a nice view of the complex structure of the water temperatures on that relatively cloud-free day over the western Great Lakes– the MODIS product indicated that SST values were as warm as 81.5º F (red enhancement) in western Lake Erie, and as cold as 35.6º F (dark blue enhancement) in western Lake Superior. Of particular interest was the north-to-south oriented plume of warmer SSTs across west-central Lake Michigan (70-75º F, yellow to orange enhancement).

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