Hurricane Danny

August 21st, 2015

GOES-14 visible (0.63 um) images [click to play MP4 animation]

GOES-14 visible (0.63 um) images [click to play MP4 animation]

1-minute interval GOES-14 SRSO-R visible images (above; click to play MP4 animation; also available as a 130 Mbyte animated GIF) showed the eye and surrounding cloud structure of Category 2 Hurricane Danny on 21 August 2015. The hazy signature of a dust-laden Saharan Air Layer (SAL) could be seen to the west, northwest, and north of the storm.

Meteosat-10 Saharan Air Layer (SAL) product [click to play animation]

Meteosat-10 Saharan Air Layer (SAL) product [click to play animation]

The compact circulation of Danny remained fairly “isolated” from the multiple pockets of SAL which stretched westward across much of the tropical Atlantic Ocean (above). The relatively clear dust-free air surrounding Danny was tropical moisture being wrapped northward into the circulation from the Intertropical Convergence Zone (ITCZ), as seen with the MIMIC Total Precipitable Water product (below).

MIMIC Total Precipitable Water product [click to enlarge]

MIMIC Total Precipitable Water product [click to enlarge]

A close-up view of Hurricane Danny (below; click image to play MP4 animation) showed some interesting detail in the convective bursts within the eyewall region, in spite of the very oblique satellite viewing angle. There is also a large (165 Mbyte) animated GIF available here.

GOES-14 visible (0.63 µm) images [click to play MP4 animation]

GOES-14 visible (0.63 µm) images [click to play MP4 animation]

Tornado in Lake Geneva, Wisconsin

August 19th, 2015
GOES-14 (left) and GOES-13 (right) 10.7 µm IR images.  Lake Geneva Wisconsin is indicated by the small white box [click to play animated GIF]

GOES-14 (left) and GOES-13 (right) 10.7 µm IR images. Lake Geneva Wisconsin is indicated by the small white box [click to play animated GIF]

An EF-1 Tornado struck Lake Geneva, WI after sunset on 18 August 2015 (SPC Storm Reports; NWS MKX report). GOES-14 was in SRSO-R mode, providing 1-minute imagery over the region; additionally, GOES-13 was in RSO mode, providing imagery about every 7 minutes. Unfortunately, GOES-14 requires two 15-minute breaks in scanning to perform housekeeping (Link); one of those periods is from 0130-0145 UTC, 13 minutes before the tornado touchdown at 0158 UTC. (GOES-R will not require these 15-minute breaks). The animation above pauses during that housekeeping time; it also slows for the ten minutes surrounding 0158 UTC. (Click here for an animation without the White Box signifying Lake Geneva).

The 0158 UTC imagery from GOES-14 (paired with the 0155 UTC imagery from GOES-13 is shown below. An overshooting top that is associated with the tornado is apparent (northeast of Lake Geneva because of the parallax shift). This overshoot is easily traceable in the 1-minute imagery, above, as it moves northeastward towards Lake Michigan. The feature also appears and can be tracked in GOES-13.

GOES-14 (left) and GOES-13 (right) 10.7 µm IR images, 0158 UTC 19 August 2015.  Lake Geneva Wisconsin is indicated by the small white box [click to enlarge]

GOES-14 (left) and GOES-13 (right) 10.7 µm IR images. Lake Geneva Wisconsin is indicated by the small white box [click to enlarge]

Automated detection of Overshooting Tops (and thermal couplets) (from this website) showed a cluster of Overshooting Tops moving over southeast Wisconsin at the time of the tornado. The number of Overshoots detected jumped about an hour before the tornado touchdown.

GOES-13 Automated Detection of Overshooting Tops (blue) and Thermal Couplets (Red) 2330 UTC 18 August 2015 - 0225 19 August 2015 [click to enlarge]

GOES-13 Automated Detection of Overshooting Tops (blue) and Thermal Couplets (Red) 2330 UTC 18 August 2015 – 0225 19 August 2015 [click to enlarge]

GOES-14 SRSO-R: central Montana wildfire

August 15th, 2015

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 µm shortwave IR images [click to play MP4 animation]

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 µm shortwave IR images [click to play MP4 animation]

A comparison of 4-km resolution GOES-15 (GOES-West), GOES-14, and GOES-13 (GOES-East) 3.9 µm shortwave infrared images (above; click to play MP4 animation; also available as a 9.4 Mbyte animated GIF) showed the development and evolution of the “hot spot” (dark black to yellow to red color enhancement) associated with a small wildfire that formed near the border of Fergus and Petroleum counties in central Montana during the afternoon hours on 15 August 2015. With GOES-15 Routine Scan mode “SUB-CONUS” sectors, images were available up to 6 times per hour (at :00, :11, :15, :30, :41, and :45); with GOES-13 in Rapid Scan Operations (RSO) mode, images were available up to 8 times per hour (at :00, :07, :15, :25, :30, :37, :45, and :55). The GOES-14 satellite had been placed into Super Rapid Scan Operations for GOES-R (SRSO-R) mode, providing images at 1-minute intervals to emulate what will be available with mesoscale sectors from the ABI instrument on GOES-R.

For the central Montana wildfire, the first unambiguous signature of a darker black wildfire hot spot began to appear on each satellite after about 1945 UTC, with the first color-enhanced pixels (signifying a shortwave IR brightness temperature of 331.9 K) showing up on the 2026 UTC GOES-14 image. The hottest fire pixel  on the GOES-15 images was 336.5 K at 2130 UTC, while the hottest fire pixel on GOES-13 images was 329.8 K at 2125 UTC. From 2120 to 2130 UTC, the hottest GOES-14 fire pixels were 341.2 K (the saturation temperature of the 3.9 µm detectors on that satellite).

With the finer spatial resolution of the shortwave IR detectors on the polar-orbiting MODIS (1-km) and VIIRS (375-meter) instruments, a fire hot spot was first detected on the 1857 UTC VIIRS image (below).

Terra/Aqua MODIS and Suomi NPP VIIRS 3.7 µm shortwave IR images [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS 3.7 µm shortwave IR images [click to enlarge]

GOES-14 SRSO-R: Wildfire in southern Washington

August 12th, 2015

GOES-14 visible (0.63 µm) images [click to play MP4 animation]

GOES-14 visible (0.63 µm) images [click to play MP4 animation]

1-minute interval GOES-14 SRSO-R visible (0.63 µm) images (above; click image to play animation) revealed the pulsing nature of the large Cougar Creek wildfire complex burning in southern Washington (not far southwest of Yakima) on 12 August 2015. The MP4 movie file is also available as a very large (128 Mbyte) animated GIF. The second fire blow-up that began around 1700 UTC apparently produced a pyrocumulonimbus cloud, with cloud-top IR Brightness Temperature (BT) values cooling past -40º C. Large amounts of smoke were transported northward and then northeastward away from the fire source region.

During the preceding overnight hours, a comparison of  1003 UTC Suomi  NPP VIIRS shortwave Infrared (3.74 µm), Day/Night Band (0.8 µm), and Infrared (11.45 µm) images (below) showed a very large shortwave IR fire “hot spot” (yellow to red to black pixels), with the large fire glowing very brightly on the Day/Night Band image; the coldest IR BT value of the cloud streaming northward from the fire was -53º C.

Suomi NPP VIIRS shortwave Infrared (3.74 µm), Day/Night Band (0.8 µm), and Infrared (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS shortwave Infrared (3.74 µm), Day/Night Band (0.8 µm), and Infrared (11.45 µm) images [click to enlarge]