Hurricane Noel remained a minimal Category 1 hurricane early in the day on 02 November 2007, although the satellite presentation was starting to deteriorate (GOES-12 IR animation) as the storm began the transition to an extratropical system. SeaWinds scatterometer data from the QuikSCAT satellite around 10:48 UTC (above, and below) did show two wind retrievals of 74 knots just to the northwest of the storm center. However, those two 74 knot wind speed points had the “Rain Flag” active (all the wind barbs with circles on the CIMSS Tropical Cyclones TCTrak display have the Rain Flag active), meaning that the presence of rainfall may have contaminated the data at those points — energy backscattered from large rain drops can constitute a significant (but unknown) portion of the measured echo energy.

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Tropical Storm Noel intensified late in the day on 01 November 2007 to become a minimal Category 1 hurricane just north of the Bahamas. AWIPS images of the GOES-12 10.7µm IR channel (above) show that the circular area of very cold cloud top temperatures (colder than -80º C, green enhancement) became more well-defined and moved closer to the surface circulation during the intensification process.

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After spending some time meandering over Cuba and just off the northern coast of the island, Tropical Storm Noel began to intensify a bit and produce bursts of convection within its eastern semicircle as it started to move slowly northward during the day on 31 October 2007. AWIPS images of the GOES-12 10.7 µm IR channel (above) revealed a significant increase in the areal coverage of very cold cloud top temperatures (below -80ºC, light green enhancement); in fact, isolated IR brightness temperatures as cold as -92º C (white pixels) were noted at 04:01 UTC on 01 November.

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Tropical Storm Noel formed in the Caribbean Sea on 28 October 2007. A GOES-12 visible image with ASCAT winds sourced from the CIMSS Tropical Cyclones site (above) shows the cloudiness associated with the tropical storm, which was centered just south of Hispaniola. An animation of GOES-12 IR channel images (below) shows that a few bursts of convection developed in the northern quadrant of Noel during the day (also apparent in a 1-km resolution GOES-12 visible image animation).

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