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.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. 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. 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. 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).
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.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.
EUMETSAT Meteosat-7 Infrared Window (11.5 µm) images (below) showed the formation of a well-defined eye after about 03 UTC.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.
===== 18 April Update =====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.
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.An interesting question from Shea Gibson:
— Shea Gibson (@WeatherFlowCHAS) April 5, 2016