Fort McMurray, Alberta wildfire

May 3rd, 2016

GOES-15 0.63 um Visible (top) and 3.9 um Shortwave Infrared (bottom) images [click to play animation]

GOES-15 0.63 um Visible (top) and 3.9 um Shortwave Infrared (bottom) images [click to play animation]

GOES-15 (GOES-West) Visible (0.63 um) and Shortwave Infrared (3.9 um) images (above) showed the hot spot (dark black to yellow to red pixels) and the development of pulses of pyrocumulonimbus (pyroCb) clouds associated with a large wildfire located just to the west of Fort McMurray, Alberta (station identifier CYMM) on 03 May 2016. The fire caused a mandatory evacuation of the estimated 80,000 residents of the city (the largest fire-related evacuation in Alberta history). Note that the hourly surface plots indicated a temperature of 90 F (32.2 C) at 22-23 UTC — a new daily high temperature record of 32.6 C was set for Fort McMurray (time series plot of surface data).

The corresponding GOES-15 Visible (0.63 um) and Infrared Window (10.7 um) images (below) revealed cloud-top infrared brightness temperature values as cold as -58 C (darker red color enhancement) at 0030 and 0100 UTC on 04 May.

GOES-15 0.63 um Visible (top) and 10.7 um Infrared Window (bottom) images [click to play animation]

GOES-15 0.63 um Visible (top) and 10.7 um Infrared Window (bottom) images [click to play animation]

Suomi NPP VIIRS False-color RGB, Visible (0.64 um), Shortwave Infrared (3.74 um), and Infrared Window (11.45 um) images at 1834 UTC [click to enlarge]

Suomi NPP VIIRS False-color RGB, Visible (0.64 um), Shortwave Infrared (3.74 um), and Infrared Window (11.45 um) images at 1834 UTC [click to enlarge]

A comparison of Suomi NPP VIIRS false-color “Snow vs cloud discrimination” Red/Green/Blue (RGB), Visible (0.64 um), Shortwave Infrared (3.74 um), and Infrared Window (11.45 um) images at 1834 UTC (above) showed that while a large fire hot spot was apparent on the Shortwave Infrared image, there was no clear indication of any pyrocumulus cloud development at that time. However, a similar image comparison at 2018 UTC (below) revealed that a well-defined pyroCb cloud had formed (with a cloud-top infrared brightness temperature as cold as -60 C, dark red color enhancement) which was drifting just to the north of the Fort McMurray airport (whose cyan surface report is plotted near the center of the images). A 2104 UTC NOAA-19 AVHRR image provided by René Servranckx showed a minimum IR brightness temperature of -59.6 C.

Suomi NPP VIIRS false-color RGB, Visible (0.64 um), Shortwave Infrared (3.74 um), and Infrared Window (11.45 um) images at 2018 UTC [click to enlarge]

Suomi NPP VIIRS false-color RGB, Visible (0.64 um), Shortwave Infrared (3.74 um), and Infrared Window (11.45 um) images at 2018 UTC [click to enlarge]

A closer look using Suomi NPP VIIRS true-color RGB and Shortwave Infrared (3.74 um) images from the SSEC RealEarth site (below) showed the initial pyroCb cloud as it had drifted just east of Fort McMurray, with the early stages of a second pyroCb cloud just south of the city.

Suomi NPP VIIRS true-color RGB and Shortwave Infrared (3.74 um) images [click to enlarge]


Suomi NPP VIIRS true-color RGB and Shortwave Infrared (3.74 um) images [click to enlarge]

A nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 um) and Shortwave Infrared (3.74 um) images at 1015 UTC or 3:15 am local time (below; courtesy of William Straka, SSEC) showed the bright glow of the large Fort McMurray wildfire, as well as the lights associated with the nearby oil shale mining activity.

Suomi NPP VIIRS Day/Night Band (0.7 um) and Shortwave Infrared (3.74 um) images at 1014 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 um) and Shortwave Infrared (3.74 um) images at 1014 UTC [click to enlarge]

A sequence of Suomi NPP VIIRS Shortwave Infrared (3.74 um) images covering the 02 April – 04 April period (below) showed the diurnal changes as well as the overall growth of the fire hot spot (darker black pixels).

Suomi NPP VIIRS Shortwave Infrared (3.74 um) images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 um) images [click to enlarge]

Sea ice off the coast of Labrador and Newfoundland, Canada

May 3rd, 2016

Suomi NPP VIIRS true-color and false-color RGB images [click to enlarge]

Suomi NPP VIIRS true-color and false-color RGB images [click to enlarge]

A comparison of Suomi NPP VIIRS true-color and false-color Red/Green/Blue (RGB) images from the SSEC RealEarth site (above) revealed the intricate structure of sea ice off the coast of Labrador, Canada on 03 May 2016. Snow cover and ice appear as shades of cyan in the false-color image (in contrast to supercooled water droplet clouds, which appear as shades of white).

A larger-scale view using GOES-13 (GOES-East) Visible (0.63 µm) images (below) showed the motion of this sea ice, which extended farther south off the coast of Newfoundland. The general southeastward ice motion was driven by the flow of the Labrador Current.

GOES-13 Visible (0.63 µm) images [click to play animation]

GOES-13 Visible (0.63 µm) images [click to play animation]

According to data from the Canadian Ice Service, the concentration of this medium to thick “first year ice” (Labrador | Labrador/Newfoundland) was as high as 9/10 to 10/10 (below). The departure of normal of portions of this ice was as high as 9/10 to 10/10 above normal.

Ice concentration off the Labrador coast [click to enlarge]

Ice concentration off the Labrador coast [click to enlarge]

Ice concentration off the coast of Labrador and Newfoundland [click to enlarge]

Ice concentration off the coast of Labrador and Newfoundland [click to enlarge]

Cyclone Fantala in the Indian Ocean

April 16th, 2016

Advanced Dvorak Technique intensity plot for Cyclone Fantala [click to enlarge]

Advanced Dvorak Technique intensity plot for Cyclone Fantala [click to enlarge]

A plot of the Advanced Dvorak Technique (ADT) hurricane intensity estimate (above) revealed that Indian Ocean Cyclone Fantala (19S) exhibited a period of rapid intensification on 15 April 2016, reaching Category 4 intensity with maximum sustained winds of 135 knots at 14 UTC.

EUMETSAT Meteosat-7 Infrared Window (11.5 µm) images (below) showed the formation of a well-defined eye after about 03 UTC.

Meteosat-7 Infrared (11.5 µm) images [click to play animation]

Meteosat-7 Infrared (11.5 µm) images [click to play animation]

A comparison of Meteosat-7 Infrared (11.5 µm) and DMSP-18 SSMI Microwave (85 GHz) images from the CIMSS Tropical Cyclones site (below) showed the eye structure around 15 UTC.

Meteosat-7 Infrared (11.5 µm) and DMSP-18 SSMI Microwave (85 GHz) images [click to enlarge]

Meteosat-7 Infrared (11.5 µm) and DMSP-18 SSMI Microwave (85 GHz) images [click to enlarge]

===== 18 April Update =====

Meteosat-7 Infrared Window (11.5 µm) images [click to play animation]

Meteosat-7 Infrared Window (11.5 µm) images [click to play animation]

During the 17-18 April period Cyclone Fantala reached Category 5 intensity (ADT plot), with maximum sustained winds of 150 knots (making it the strongest tropical cyclone on record in the South Indian Ocean); Fantala also became the longest-lived hurricane-strength tropical cyclone on record for that ocean basin. Meteosat-7 Infrared Window (11.5 µm) images (above) showed the storm reaching peak intensity as it moved just north of the island of Madagascar.

A comparison of Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images (below) offered a detailed nighttime view of the eye of Fantala at 2249 UTC on 17 April. Side lighting from the Moon (in the Waxing Gibbous phase, at 81% of full) helped to cast a distinct shadow within the eye, and also provided a good demonstration of the “visible image at night” capability of the Day/Night Band.

 

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm images [click to enlarge]

Middle and upper-atmospheric wave structures in the vicinity of a subtropical jet stream

April 4th, 2016

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with ECMWF model maximum wind isotachs [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with ECMWF model maximum wind isotachs [click to enlarge]

A strong (120-knot) subtropical jet stream was moving eastward across the Gulf of Mexico during the 03 April – 04 April 2016 period. During the overnight hours between these 2 days, a Suomi NPP VIIRS Day/Night Band (0.7 µm) image at 0753 UTC (above) revealed a large packet of arc-shaped mesospheric airglow waves south of the axis of the jet stream (as indicated by isotachs of the maximum tropospheric wind speed from the ECMWF model). Note how there were no cloud features which corresponded to these waves in the 0753 UTC VIIRS Infrared Window (11.45 µm) image; since the Moon was in the waning Gibbous phase (at 13% of Full), there was very little lunar illumination of cloud features, so airglow — essentially the “night glow” emitted from a variety of high-altitude (80-105 km) gases (primarily the sodium layer) near the mesopause — was allowing these high-altitude waves to be detected using the sensitive Day/Night Band (reference: “Suomi satellite brings to light a unique frontier of nighttime environmental sensing capabilities”).

During the subsequent daytime hours on 04 April, more interesting (tropospheric) waves were seen in the vicinity of this subtropical jet stream — small packets of waves that were propagating westward, against the ambient flow –one over Florida/Georgia/South Carolina, and another over South Texas. Unfortunately, these features fall into the “What the heck is this?” blog category, so no coherent explanation of them can be offered at this time.

GOES-13 Water Vapor (6.5 µm) images, with ECMWF model maximum wind isotachs [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with ECMWF model maximum wind isotachs [click to play animation]

An interesting question from Shea Gibson: