Heavy Rainfall in Southeast Texas

May 27th, 2016

GOES-13 Infrared Window (10.7 µm) images [click to play animation]

GOES-13 Infrared Window (10.7 µm) images [click to play animation]

4-km resolution GOES-13 (GOES-East) Infrared Window (10.7 µm) images (above) showed the cold cloud tops associated with training and back-building thunderstorms that produced very heavy rainfall (along with some hail and damaging winds) in parts of Southeast Texas during the 26 May27 May 2016 period. The images are centered on Brenham, Texas (station identifies K11R), where over 19 inches of rainfall was reported in a 24-hour period (NWS Houston PNS). Note the presence of very cold cloud-top IR brightness temperatures of -80º C or colder (violet color enhancement).

During the overnight hours, a comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0801 UTC or 3:01 am local time (below) revealed cloud-top gravity waves propagating northwestward away from the core of overshooting tops (which exhibited IR brightness temperatures as cold as -84º C) located just to the west of Brenham. Due to ample illumination from the Moon — which was in the Waning Gibbous phase, at 71% of Full — the “visible image at night” capability of the VIIRS Day/Night Band (DNB) was well-demonstrated. The bright white streaks seen on the DNB image are a signature of cloud-top illumination by intense lightning activity.

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

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

A time series plot of surface weather conditions at Brenham is shown below.

Time series plot of surface weather conditions at Brenham, Texas [click to enlarge]

Time series plot of surface weather conditions at Brenham, Texas [click to enlarge]

===== 28 May Update =====

Landsat-8 false-color RGB image [click to enlarge]

Landsat-8 false-color RGB image [click to enlarge]

A 30-meter resolution Landsat-8 false-color Red/Green/Blue (RGB) image viewed using the RealEarth web map server (above) showed widespread areas of inundation (darker shades of blue) along the Brazos River and some of its tributaries, just to the east and north of Brenham, Texas.

 

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 µm Visible (top) and 3.9 µm Shortwave Infrared (bottom) images [click to play animation]

GOES-15 (GOES-West) Visible (0.63 µm) and Shortwave Infrared (3.9 µm) 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 — which started on 01 May (Wikipedia) — caused a mandatory evacuation of the nearly 90,00 residents of the city (the largest fire-related evacuation in Alberta history). Note that the hourly surface plots indicated a temperature of 90º F (32.2º C) at 22-23 UTC — in fact, a new daily record high temperature of 32.6º C was set for Fort McMurray (time series plot of surface data).

The corresponding GOES-15 Visible (0.63 µm) and Infrared Window (10.7 µm) images (below) revealed cloud-top infrared brightness temperature values as cold as -58º 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 µm Visible (top) and 10.7 µm 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 µm), Shortwave Infrared (3.74 µm), and Infrared Window (11.45 µm) 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 µm), Shortwave Infrared (3.74 µm), and Infrared Window (11.45 µm) 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 -60º 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 -59.6º 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 µm), Shortwave Infrared (3.74 µm), and Infrared Window (11.45 µm) images at 2018 UTC [click to enlarge]

A closer look using Suomi NPP VIIRS true-color RGB and Shortwave Infrared (3.74 µm) 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 µm) images [click to enlarge]

A nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) 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 µm) and Shortwave Infrared (3.74 µm) images at 1014 UTC [click to enlarge]

A sequence of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) 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 µm) images [click to enlarge]

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

===== 05 May Update =====

The GOES-14 satellite was operating in Super Rapid Scan Operations for GOES-R (SRSOR) mode, providing images at 1-minute intervals — and the scan sector was positioned to monitor the Fort McMurray wildfire on 05 May. GOES-14 Visible (0.63 µm) and Shortwave Infrared (3.9 µm) images (below; also available as a large 133 Mbyte animated GIF) showed the growth of the smoke plume and fire hot spot signature (black to yellow to red pixels).

GOES-14 0.63 µm Visible (top) and 3.9 µm Shortwave Infrared (bottom) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (top) and 3.9 µm Shortwave Infrared (bottom) images [click to play MP4 animation]


A 30-meter resolution Landsat-8 false-color Red/Green/Blue (RGB) image (below) showed the size of part of the fire burn scar (darker brown) as well as the active fires (bright pink) along the perimeter of the burn scar.

Landsat-8 false-color image [click to enlarge]

Landsat-8 false-color image [click to enlarge]

===== 06 May Update =====

The Fort McMurray fire continued to produce a great deal of smoke on 06 May, and the coverage and intensity of fire hot spots increased during the afternoon hours as seen on 1-minute GOES-14 Visible (0.63 µm) and Shortwave Infrared (3.9 µm) images (below; also available as a large 180 Mbyte animated GIF).

GOES-14 0.63 µm (top) and 3.9 µm Shortwave Infrared (bottom) images [click to play MP4 animation]

GOES-14 0.63 µm (top) and 3.9 µm Shortwave Infrared (bottom) images [click to play MP4 animation]

===== 13 May Update =====

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

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

A comparison of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images at 0906 UTC or 3:06 am local time (above) showed the fire hot spots (dark gray to yellow to red pixels) and their nighttime glow.

A time series of VIIRS Shortwave Infrared (3.74 µm) images covering the 04-13 May period (below) revealed the rapid early growth of the fire, and the continued slow spread of the fire periphery toward the Alberta/Saskatchewan border. On 13 May the total size of the area burned by the Fort McMurray fire was estimated to be 241,000 hectares or 595,524 acres.

Time series of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images, covering the 04-13 May period [click to enlarge]

Time series of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images, covering the 04-13 May period [click to enlarge]

===== 16 May Update =====

GOES-15 0.63 µm Visible (left) and 3.9 µm shortwave Infrared (right images [click to play animation]

GOES-15 0.63 µm Visible (left) and 3.9 µm shortwave Infrared (right images [click to play animation]

Strong southerly winds ahead of an approaching trough axis (surface analyses) created favorable conditions for rapid fire growth on 16 May — GOES-15 Visible (0.63 µm) and Shortwave Infrared (3.74 µm) images (above) showed the development of pyrocumulus clouds (first on the far western flank of the fire around 1930 UTC, then later in the eastern portion of the fire area). This new flare-up of fire activity prompted additional evacuations of some oil sands work camps and facilities north of Fort McMurray.

A comparison of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 1932 UTC (below) showed that a small pyroCb had developed, which exhibited a cloud-top IR brightness temperature of -41.48 C.

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm), and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm), and Infrared Window (11.45 µm) images [click to enlarge]

A toggle between the corresponding VIIRS true-color RGB image and Shortwave Infrared images is shown below.

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

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

A time series plot of surface weather conditions for Fort McMurray (below) shows that during prolonged periods of light winds, the surface visibility dropped below 1 mile at times. The air quality at Fort McMurray was rated as “extreme“, and deemed unsafe for residents to return to the city.

Time series of weather conditions at Fort McMurray on 16 May [click to enlarge]

Time series of weather conditions at Fort McMurray on 16 May [click to enlarge]

===== 17 May Update =====

GOES-15 0.63 µm Visible (left) and 3.9 µm Shortwave Infrared (right) images [click to play animation]

GOES-15 0.63 µm Visible (left) and 3.9 µm Shortwave Infrared (right) images [click to play animation]

A shift to westerly winds followed the passage of a surface trough axis on 17 May (surface analyses), which slowed the northward progress of the fire. GOES-15 Visible (0.63 µm) and Shortwave Infrared (3.9 µm) images (above; also available as an MP4 animation) continued to show a great deal of thick smoke over the region, with hot spots from active fires.

However, during the afternoon hours multiple pyroCb clouds were seen to develop along the eastern flank of the fire. A comparison of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 2054 UTC (below) revealed the pyroCb clouds, which exhibited cloud-top IR Window brightness temperatures as cold as -57º C (darker orange color enhancement).

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 m) and Infrared Window (11.45 ) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 m) and Infrared Window (11.45 ) images [click to enlarge]

A comparison of GOES-15 Shortwave Infrared (3.9 µm) and Infrared Window (10.7 µm) images (below; also available as an MP4 animation) showed the development of the pyroCb clouds around 2000 UTC, whose anvil debris moved rapidly southeastward; these pyroCb clouds exhibited a darker gray appearance on the shortwave IR images, along with cloud-top IR Window brightness temperatures as cold as -52º C (light orange color enhancement). Lightning strikes were detected during the early stages of pyroCb growth.

GOES-15 3.9 µm Shortwave Infrared (left) and 10.7 µm Infrared Window (right) images [click to play animation]

GOES-15 3.9 µm Shortwave Infrared (left) and 10.7 µm Infrared Window (right) images [click to play animation]

===== 18 May Update =====

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images covering the 04-18 May 2016 period [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images covering the 04-18 May 2016 period [click to enlarge]

Daily Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images covering the period 04 May to 18 May 2016 are shown above. The rapid growth of the perimeter of fire hot spots (yellow to red color enhancement) is quite evident during the first few days; patches of thick cloud cover tended to mask the fire hot spots during the middle of the period, but then another increase in hot spot growth is seen beginning on 16 May.

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]