Hurricane Igor intensifies to a Category 2 storm

September 12th, 2010
SSMI/S 85 GHz microwave brightness temperature image

SSMI/S 85 GHz microwave brightness temperature image

An SSMI/S 85 GHz microwave brightness temperature image from the CIMSS Tropical Cyclones site (above) displayed a well-defined eyewall structure associated with Hurricane Igor ar 11:32 UTC on 12 September 2010.

GOES-13 1-km resolution 0.63 µm visible channel images (below) showed an improving appearance to the eye of Igor during the morning hours.

GOES-13 0.63 µm visible channel images

GOES-13 0.63 µm visible channel images

========== UPDATE ==========

GOES-13 10.7 µm IR images

GOES-13 10.7 µm IR images

Igor rapidly intensified into a Category 4 hurricane later in the day. GOES-13 4-km resolution 10.7 µm IR images (above) displayed a well-defined eye, while a plot of the CIMSS Advanced Dvorak Technique (below) showed the trend of rapid intensification.

Plot of the CIMSS Advanced Dvorak Technique (ADT)

Plot of the CIMSS Advanced Dvorak Technique (ADT)

1-km resolution GOES-13 0.63 µm visible channel images (below) showed a fairly nice eye structure during the daytime hours.

GOES-13 0.63 µm visible channel images

GOES-13 0.63 µm visible channel images

Igor becomes the 4th Atlantic Basin hurricane of the 2010 season

September 11th, 2010
GOES-13 10.7 µm IR images

GOES-13 10.7 µm IR images

Hurricane Igor became the 4th hurricane of the season in the Atlantic Basin late in the day on 11 September 2010. GOES-13 10.7 µm IR images from the CIMSS Tropical Cyclones site (above) displayed an increasingly organized structure to the convection surrounding the center of the storm. Igor existed in an environment of low deep layer wind shear, which was a favorable factor for further intensification.

The development of a few convective bursts near the center of Igor’s circulation could be seen on GOES-13 0.63 µm visible images (below), suggesting the formation of an eyewall.

GOES-13 0.63 µm visible images

GOES-13 0.63 µm visible images

A 22:56 UTC microwave image from the SSMI/S instrument (below) revealed a well-defined convective ring around the center of Igor.

SSMI/S 85 GHz mircrowave brightness temperature

SSMI/S 85 GHz mircrowave brightness temperature

Deadly natural gas explosion and fire in San Bruno, California

September 10th, 2010
GOES-11 / GOES-15 / GOES-13 3.9 µm shortwave IR images

GOES-11 / GOES-15 / GOES-13 3.9 µm shortwave IR images

A large natural gas explosion occurred in San Bruno, California on the evening of 09 September 2010, which killed 4 people and destroyed 38 homes. McIDAS images of GOES-11 (GOES-West), GOES-15, and GOES-13 (GOES-East) 3.9 µm shortwave IR channel data (above) showed the resulting fire “hot spots” (black to yellow color enhancement) during the 01:00 UTC to 04:00 UTC time period (6 pm to 9 pm local time).

The plot below shows that the maximum 3.9 µm shortwave IR pixel brightness temperatures were seen on the 01:15 UTC (6:15 pm local time) GOES-15 and GOES-13 images, and 30 minutes later at 01:45 UTC (6:45 pm local time) on the GOES-11 images.

Plot of GOES-11, GOES-15, and GOES-13 3.9 µm IR brightness temperatures

Plot of GOES-11, GOES-15, and GOES-13 3.9 µm IR brightness temperatures

A comparison of the 1-km resolution NOAA-16 AVHRR 3.7 µm and the 4-km resolution GOES-11 3.9 µm shortwave IR images (below) showed the fire hot spot (black pixels) around 02:00 UTC (7:00 pm local time). Note the more accurate placement of the fire hot spot on the AVHRR image — San Bruno is located more toward the eastern side of the San Francisco Peninsula.

NOAA-16 AVHRR 3.7 µm shortwave IR and GOES-11 3.9 µm shortwave IR images

NOAA-16 AVHRR 3.7 µm shortwave IR and GOES-11 3.9 µm shortwave IR images

AWIPS images of the 1-km resolution MODIS 3.7 µm shortwave IR channel and the 4-km resolution GOES-11 3.9 µm shortwave IR data around 06:00 UTC (11:00 pm local time) can be seen below. Although no fire hot spot was evident on the GOES-11 image, a small cluster of yellow pixels could still be seen on the MODIS image.

MODIS 3.7 µm shortwave IR and GOES-11 3.9 µm shortwave IR images

MODIS 3.7 µm shortwave IR and GOES-11 3.9 µm shortwave IR images

Development of a “warm conveyor belt” signature near the back edge of Tropical Storm Earl?

September 4th, 2010
GOES-13 6.5 µm water vapor images (with surface fronts analyses)

GOES-13 6.5 µm water vapor images (with surface fronts analyses)

AWIPS images of the GOES-13 6.5 µm water vapor channel data (above) showed Hurricane / Tropical Storm Earl as it moved inland across the Canadian Maritime provinces on 04 September05 September 2010. However, at the same time a large mid-latitude cyclone was intensifying over far western Quebec — and the water vapor imagery began to display what appeared to be a warm conveyor belt signature (below) that stretched northwestward across Quebec and over Hudson Bay. It was somewhat surprising to see such a warm conveyor belt signature develop so close to the proximity of the back edge of the cloud shield of Earl.

GOES-13 water vapor image (with surface front analysis)

GOES-13 water vapor image (with surface front analysis)

The GFS40 model winds within the 315-325 K isentropic layer (below) indicated that there was a strong 60-knot jet moving across the region where the warm conveyor belt signature formed on the water vapor imagery.

GOES-13 water vapor image + GFS 315-325 K layer winds

GOES-13 water vapor image + GFS 315-325 K layer winds

A pair of 1-km resolution MODIS 6.7 µm water vapor images (below) showed greater detail of the structure of the warm conveyor belt signature as it was forming.

MODIS 6.7 µm water vapor images

MODIS 6.7 µm water vapor images

A sequence of four 1-km resolution POES AVHRR 10.8 µm IR images (below) showed the banding structure that was forming within the conveyor belt feature.

AVHRR 10.8 µm IR images

AVHRR 10.8 µm IR images