3 tropical cyclones in the Atlantic Basin: Igor, Julia, and Karl

September 14th, 2010
Atlantic Basin GOES-13 IR images

Atlantic Basin GOES-13 IR images

GOES-13 10.7 µm IR images (above) showed 3 tropical cyclones in the Atlantic Basin on 14 September 2010: from left to right, Tropical Storm Karl, Hurricane Igor, and Hurricane Julia. Real-time visible and IR images covering the Tropical Atlantic are available from NOAA/NESDIS/OSDPD/SSD.

A comparison of geostationary-orbiting satellite IR images and polar-orbiting microwave images (from the CIMSS Tropical Cyclones site) for each of the 3 tropical cyclones are shown below. Note that there is a 1-2 hour difference between the IR images and the microwave images — however, these comparisons show the utility of the microwave images for showing tropical cyclone structures that are often masked by the cold convective cloud shield.

Tropical Storm Karl: geostationary IR image + polar microwave image

Tropical Storm Karl: geostationary IR image + polar microwave image

Hurricane Igor: geostationary IR image + polar microwave image

Hurricane Igor: geostationary IR image + polar microwave image

Hurricane Julia: geostationary IR image + polar microwave image

Hurricane Julia: geostationary IR image + polar microwave image

An AWIPS image of EUMETSAT METOP Advanced Scatterometer (ASCAT) winds (below) indicated surface winds as high as 63 knots near the center of Hurricane Igor at 13:28 UTC; however, ASCAT winds are known to have a low speed bias (which increases as winds get to higher speeds).

EUMETSAT METOP ASCAT winds

EUMETSAT METOP ASCAT winds

As part of the GOES-15 Post Launch Science Test, the satellite was placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5 minutes during the day. The evolution of the eye of Hurricane Igor is seen on GOES-15 0.63 µm visible channel images (below; also available as a QuickTime movie) — note the occasional presence of small mesovortices within the eye region.

GOES-15 0.63 µm visible channel images

GOES-15 0.63 µm visible channel images

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