Pyrocumulonimbus cloud in Bolivia

August 18th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.35 µm, bottom) images [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the formation of a pyrocumulonimbus (pyroCb) cloud over far southeastern Bolivia on 18 August 2019. The small anvil cloud briefly surpassed the -40ºC pyroCb threshold from 1800-1820 UTC, attaining a minimum cloud-top infrared brightness temperature of -45.2ºC along the Bolivia/Paraguay border at 1800 UTC. This pyroCb formed over the hottest southern portion of an elongated fire line, as seen in the Shortwave Infrared imagery.

A 1.5-day animation of GOES-16 Shortwave Infrared images (from 12 UTC on 17 August to 2350 UTC on 18 August) revealed the rapid southeastward run of the fire to the Bolivia/Paraguay border on 17 August, followed by the eastward expansion of the fire line on 18 August (below).

GOES-16 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

GOES-16 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

A toggle between Suomi NPP VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images as viewed using RealEarth (below) showed the large and dense smoke plume streaming southeastward, with the small pyroCb along the Bolivia/Paraguay border at 1745 UTC — the brighter white tops of the pyrocumulus and pyrocumulonimbus clouds reached higher altitudes than the tan-colored smoke plume. The coldest cloud-top infrared brightness temperature was about -55ºC (orange enhancement), which corresponded to an altitude around 9 km according to rawinsonde data from Corumbá, Bolivia.

Suomi NPP VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images [click to enlarge]


Strong northerly to northwesterly surface winds were blowing across the region, in advance of an approaching cold front (surface analyses) — at Robore, Bolivia (located just north-northwest of the fires), winds were gusting to 25-28 knots during much of the day (below).

Time series of surface report data from Robore, Bolivia [click to enlarge]

Time series of surface report data from Robore, Bolivia [click to enlarge]

This is likely the second confirmed case of a South American pyroCb (the first being on 29 January 2018) — in addition, it’s the second pyroCb documented in the tropics and the first pyroCb documented during a winter season. Thanks to Mike Fromm (NRL) for bringing this case to our attention!

Super Typhoon Lekima in the West Pacific Ocean

August 8th, 2019 |

Himawari-8

Himawari-8 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.4 µm, right) images [click to play animation | MP4]

JMA 2.5-minute rapid scan Himawari-8 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.4 µm) images (above) showed the eye and eyewall region of Category 4 Super Typhoon Lekima on 07-08 August 2019. Features of interest included surface mesovortices within the eye, eyewall cloud-top gravity waves, and a quasi-stationary “cloud cliff” notch extending northwestward from the eye (infrared brightness temperature contours). This cloud cliff feature has been observed with other intense tropical cyclones (for example, Typhoon Neoguri in 2014).

VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 as viewed using RealEarth are shown below.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

The trochoidal motion (or wobble) of the eye of Lekima became very pronounced as it crossed the Ryukyu Islands, as seen in an animation of 2.5-minute rapid scan Himawari-8  Infrared images (below). The center of the tropical cyclone moved between Miyakojima (ROMY) and Ishigakijima (ROIG), which reported wind gusts to 67 knots and 64 knots respectively.

Himawari-8 Infrared (10.4 µm) images [click to play animation| MP4]

Himawari-8 “Clean” Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 Infrared images with contours and streamlines of deep-layer wind shear at 15 UTC from the CIMSS Tropical Cyclones site (below) indicated that Lekima was moving through an environment of very low shear, which was a factor aiding its intensification.

Himawari-8 "Clean" Infrared Window (10.4 µm) images, with contours and streamlines of deep-layer wind shear at 15 UTC [click to play animation]

Himawari-8 “Clean” Infrared Window (10.4 µm) images, with contours and streamlines of deep-layer wind shear at 15 UTC [click to play animation]

Severe weather in Minnesota and Wisconsin

July 19th, 2019 |

GOES-16 "Red" Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the development and propagation of a Mesoscale Convective System (MCS) that produced hail up to 3.0 inches in diameter in Minnesota and wind gusts to 84 mph and a few tornadoes in Wisconsin (SPC Storm Reports | NWS Twin Cities | MN DNR | NWS Green Bay) on 19 July 2019. Numerous overshooting tops and widespread storm-top gravity waves were evident in the imagery, along with a few Above-Anvil Cirrus Plume features extending northeastward from some of the overshooting tops around sunset. Also notable were the inflow feeder bands that were streaming northward into the southern flank of the MCS across Minnesota.

A comparison of GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (below) revealed cloud-top infrared brightness temperatures as cold as -86ºC over northwestern Wisconsin.

GOES-16

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play MP4 animation]

As the MCS persisted into the subsequent nighttime hours, GOES-16 Infrared images (below) showed the large canopy of cold cloud tops, with infrared brightness temperatures of -80ºC or colder (violet pixels).  Some of the embedded storms exhibited well-defined Enhanced-V storm top signatures (for example, at 2219 UTC).

GOES-16

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

===== 22 July Update =====

Terra MODIS True Color RGB images, 11 July vs 22 July [click to enlarge]

Terra MODIS True Color RGB images, 11 July vs 22 July [click to enlarge]

A comparison of Terra MODIS True Color Red-Green-Blue (RGB) images from 11 July and 22 July (above) showed the subtle NW-SE oriented swath of downed trees across northeastern Wisconsin. A 14 July vs 22 July comparison as viewed using RealEarth is shown below — the swath extended from approximately Pickerel to Mountain.

14 July and 22 July Terra MODIS True Color RGB images [click to enlarge]

Terra MODIS True Color RGB images, 14 July vs 22 July [click to enlarge]

In 22 July Terra MODIS images displayed using AWIPS (below), the swath of downed trees was brighter (more reflective) in the Near-Infrared “Snow/Ice” (1.61 µm), warmer (darker shades of orange to red) in the Shortwave Infrared (3.7 µm) and Land Surface Temperature, and lighter shades of green in the Normalized Difference Vegetation Index.

Terra MODIS Visible (0.65 µm), Near-Infrared "Snow/Ice" (1.61 µm), Shortwave Infrared (3.7 µm), Land Surface Temperature and Normalized Difference Vegetation Index images on 22 July [click to enlarge]

Terra MODIS Visible (0.65 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.7 µm), Land Surface Temperature and Normalized Difference Vegetation Index images on 22 July [click to enlarge]

The swath of downed trees was also seen in GOES-16 Normalized Difference Vegetation Index images (below), showing up as a darker shade of green with that product’s default enhancement.

GOES-16 Normalized Difference Vegetation Index images [click to play animation]

GOES-16 Normalized Difference Vegetation Index images on 22 July [click to play animation]

Eruption of the Raikoke volcano in the Kuril Islands

June 21st, 2019 |

Himawari-8 False Color RGB images [click to play animation | MP4]

Himawari-8 False Color RGB images [click to play animation | MP4]

For the first time since 1924, a major eruption of the Raikoke volcano occurred around 1800 UTC on 21 June 2019. Himawari-8 False Color Red-Green-Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed — via the brighter yellow areas — that a large portion of the volcanic plume was rich in both ash and sulfur dioxide (SO2). The Tokyo VAAC estimated the maximum ash height to be 43,000 feet (~13 km) above ground level — and CALIPSO CALIOP data indicated a maximum ash height around 12 km shortly after 02 UTC on 22 June (between 45-50º N latitude and 159-161º E longitude).

A comparison of an Aqua MODIS False Color RGB image with the corresponding Ash Height, Ash Loading and Ash Effective Radius retrieved products at 0310 UTC on 22 June (below) indicated maximum ash height values of 18-20 km (black pixels) immediately downwind of the eruption site. Maximum Himawari-8 Ash Height values were in the 16-18 km range.

Aqua MODIS False Color RGB, Ash Height, Ash Loading and Ash Effective Radius at 0310 UTC on 22 June [click to enlarge]

Aqua MODIS False Color RGB image with Ash Height, Ash Loading and Ash Effective Radius retrieved products [click to enlarge]

In a comparison of Himawari-8 Upper-level (6.2 µm), Mid-level (6.9 µm) and Low-level (7.3 µm) Water Vapor images (below), since the 7.3 µm spectral band is also sensitive to SO2 absorption, those images showed a good signature of the leading filament of volcanic SO2 as it was transported east-southeastward over the North Pacific Ocean.

Water Vapor images from Himawari-8: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Water Vapor images from Himawari-8: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Similarly, the GOES–17 (GOES-West) Low-level Water Vapor (7.3 µm) images also showed the filament of volcanic SO2 that was being drawn into the circulation of a Gale Force Low south of the Aleutian Islands. As a result, the Anchorage VAAC issued aviation Volcanic Ash Advisories that covered large areas of the North Pacific Ocean and southern Bering Sea; they continued to estimate the maximum ash height to be 43,000 feet. Around 16 UTC on 22 June, CALPSO CALIOP data sampled a small portion of the ash at an altitude near 17 km (between 45-50º N latitude, 155-157º W longitude).

Water Vapor images from GOES-17: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Water Vapor images from GOES-17: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth are shown below at approximately 01 UTC, 02 UTC and 03 UTC on 22 June. The combination of True Color and Infrared imagery indicated that volcanic ash was present a multiple altitudes.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP at 01, 02 and 03 UTC on 22 June [click to enlarge]

Due to the highly-oblique satellite viewing angle of GOES-17, multiple Raikoke eruption pulses of significant vertical extent were clearly evident in GOES-17 “Red” Visible (0.64 µm) images (below).

GOES-17

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

A somewhat less oblique view from the west was provided by the NSMC FY-2G satellite (below).

NSMC FY-2G Visible (0.73 µm) images [click to play animation | MP4]

NSMC FY-2G Visible (0.73 µm) images [click to play animation | MP4]

Himawari-8 “Red” Visible (0.64 µm) images (below) provided another interesting view of the multiple eruption pulses — and since the eruption began around 5 AM local time, long early morning shadows were cast by the initial bursts of tall volcanic clouds. A faster animation revealed shock waves propagating radially outward from the eruption site.

Himawari-8

Himawari-8 “Red” Visible (0.64 µm) images [click to play animation | MP4]




Incidentally, an astronaut aboard the International Space Station took a photo of the volcanic cloud at 2246 UTC on 21 June — and the two Visible images that bracket that time (2240 and 2250 UTC) from GOES-17 and Himawari-8 are shown below.

Photo taken by an astronaut on the International Space Station [click to enlarge]

Photo taken by an astronaut on the International Space Station at 2246 UTC [click to enlarge]

GOES-17 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

GOES-17 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

Himawari-8 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

Himawari-8 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

===== 23 June Update =====

Himawari-8 False Color RGB images [click to play MP4 animation]

Himawari-8 False Color RGB images [click to play MP4 animation]

A 2-day animation of 10-minute Himawari-8 False Color images (above) showed the ash- and SO2-rich volcanic plume (brighter shades of yellow) eventually being transported northeastward across the western Aleutian Islands and circulating cyclonically over the Bering Sea. Similarly, this volcanic cloud transport was also seen in the corresponding GOES-17 False Color imagery.

===== 24 June Update =====

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB imagery (above) continued to show a signature of the volcanic cloud (brighter shades of yellow) from the Raikoke eruption over a large portion of the Bering Sea on 24 June. Volcanic ash advisories were issued for flight altitudes as high as 40,000 feet — and a pilot report of SO2 over the Bering Sea at 47,000 feet was received at 1822 UTC (below).

GOES-17 SO2 RGB, Split Clout Top Phase (11.2-8.4 µm) and Dust RGB images, with a pilot report of SO2 [click to enlarge]

GOES-17 SO2 RGB, Split Clout Top Phase (11.2-8.4 µm) and Dust RGB images, with a pilot report of SO2 [click to enlarge]

===== 25 June Update =====

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images (above) showed the persistent signature of the SO2-rich volcanic cloud as much of it remained within the circulation of a quasi-stationary low pressure system in the Bering Sea.

An interesting Pilot Report north of the Aleutians at 36,000 feet (below) noted thin grey-colored layers below the altitude of the aircraft. GOES-17 Air Mass RGB images showed a subtle brown/tan plume — could this have been a thin filament of ash from the Raikoke eruption that was drawn into the circulation of the Bering Sea low?

GOES-17 SO2 RGB, Air Mass RGB, Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2008 UTC Pilot Report [click to enlarge]

GOES-17 SO2 RGB, Air Mass RGB, Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2008 UTC Pilot Report [click to enlarge]

Another Pilot Report farther to the west at 2119 UTC (below) was close to the southern edge of the GOES-17 SO2 signatures, but no sulphur odor was reported; however, they did note the presence of an apparent ash layer south of Shemya in the western Aleutian Islands.

GOES-17 SO2 RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2119 UTC Pilot Report [click to enlarge]

GOES-17 SO2 RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2119 UTC Pilot Report [click to enlarge]