Tropical Cyclone Veronica north of Australia

March 21st, 2019 |

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (1145 µm) images at 1716 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1716 UTC [click to enlarge]

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above) showed Category 4 Cyclone Veronica off the northern coast of Western Australia at 1716 UTC on 21 March 2019. Ample illumination from a Full Moon maximized the “visible image at night” capability of the Day/Night Band.

In a comparison of Microwave images from Suomi NPP ATMS at 1716 UTC and from GCOM-W1 AMSR2 at 1732 UTC (below), an eyewall that was nearly completely closed was apparent. Suomi NPP and GCOM-W1 images courtesy of William Straka, CIMSS.

Microwave images from Suomi NPP ATMS at 1716 UTC and from GCOM-W1 AMSR2 at 1732 UTC [click to enlarge]

Microwave images from Suomi NPP ATMS at 1716 UTC and from GCOM-W1 AMSR2 at 1732 UTC [click to enlarge]

A DMSP-17 SSMIS Microwave (85 GHz) image at 2246 UTC from the CIMSS Tropical Cyclones site is shown below. The deep-layer Wind Shear at 21 UTC was low (green contours), and Sea Surface Temperature values were quite high — both factors favorable for continued intensification as Veronica moved slowly toward the coast.

DMSP-17 SSMIS Microwave (85 GHz) image at 2246 UTC, with an overlay of 21 UTC deep-layer Wind Shear, and Sea Surface Temperature [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 2246 UTC, with an overlay of 21 UTC deep-layer Wind Shear, and Sea Surface Temperature [click to enlarge]

2.5-minute interval rapid scan Himawari-8 Infrared Window (10.4 µm) images (below) showed increasing organization to the eyewall structure. At times the cloud-top infrared brightness temperatures were -90ºC and colder (yellow pixels embedded within darker purple). Note: the rapid scan sector was re-poositioned eastward at 0100 UTC (to monitor Cyclone Trevor), so 10-minute imaging resumed after that time.

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

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

After sunrise, rapid scan Himawari-8 “Red” Visible (0.64 µm) images (below) revealed that the large eye was completely cloud-filled.

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

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

Chemical plant fire near Houston, Texas

March 18th, 2019 |

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]

GOES-16 (GOES-East) Shortwave Infrared (3.9 µm) images (above) revealed the thermal anomaly or “hot spot” of a fire burning at the Intercontinental Terminals Company petrochemical plant in Deer Park, Texas on 18 March 2019. Although the thermal signature was often partially masked by the passage of high clouds overhead, it was still evident for much of the time period (0202-1457 UTC, or 9:02pm-9:57am CDT). The fire started around 1530 UTC (10:30am CDT) on 17 March.

Comparisons of 2-km resolution (at satellite subpoint) GOES-16 Shortwave Infrared and 375-meter resolution VIIRS Shortwave Infrared (3.74 µm) imagery from Suomi NPP (at 0741 UTC) and NOAA-20 (at 0835 UTC) are shown below. The thermal signature is better defined and more accurately located using the higher-resolution VIIRS imagery.

Shortwave Infrared images from Suomi NPP VIIRS (3.74 µm) and GOES-16 (3.9 µm) at 0741 UTC [click to enlarge]

Shortwave Infrared images from Suomi NPP VIIRS (3.74 µm) and GOES-16 (3.9 µm) at 0741 UTC [click to enlarge]

Shortwave Infrared images from NOAA-20 VIIRS (3.74 µm) and GOES-16 (3.9 µm) at 0835 UTC [click to enlarge]

Shortwave Infrared images from NOAA-20 VIIRS (3.74 µm) and GOES-16 (3.9 µm) at 0835 UTC [click to enlarge]

A comparison of 1-km resolution NOAA-19 AVHRR and 2-km resolution GOES-16 Shortwave Infrared images at 1132 UTC is shown below. This happened to be at a time when the GOES-16 thermal signature was being masked by high clouds overhead. The fire was located northeast of the Houston Hobby (station identifier KHOU) and Ellington (station identifier KEFD) airports.

Shortwave Infrared images from NOAA-19 (3.7 µm) and GOES-16 (3.9 µm) at 1132 UTC [click to enlarge]

Shortwave Infrared images from NOAA-19 (3.7 µm) and GOES-16 (3.9 µm) at 1132 UTC [click to enlarge]

In a sequence of GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below), the dark-colored smoke plume was most obvious in the Near-Infrared imagery — this is due to the fact that vegetation is more reflective at those wavelengths, helping to enhance the smoke/surface contrast. The smoke had drifted as far westward as Austin and Kerrville, a distance of over 100 miles.

GOES-16 "Red" Visible (0.64 µm), Near-Infrared "Vegetation" (0.86 µm) and Near-Infrared "Snow/Ice" (1.61 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

===== 19 March Update =====

GOES-16 "Red" Visible (0.64 µm), Near-Infrared "Vegetation" (0.86 µm), and Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

The Deer Park Fire continued to burn uncontrolled on 19 March — 1-minute Mesoscale Domain Sector GOES-16 Visible, Near-Infrared and Shortwave Infrared images (above) showed that while the passage of mid/upper-level clouds often obscured the dark-colored smoke plume, a signature of the hot thermal anomaly was seen almost continuously. Note that the color enhancement applied to the Shortwave Infrared imagery is different from the one used in the 18 March examples.

Flooding in South Dakota, Nebraska and Iowa

March 15th, 2019 |

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Vegetation” (0.86 µm) and “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) Near-Infrared “Vegetation” (0.86 µm) and “Snow/Ice” (1.61 µm) images (above) revealed widespread river flooding (in the wake of rapid snow melt and heavy rainfall) across parts of southeastern South Dakota, eastern Nebraska and western/central Iowa on 15 March 2019. Water and flooded land appear as darkest shades of gray to black on both sets of images —  remaining snow cover also appeared as darker shades on the 1.61 µm imagery. Additional information regarding the flooding is available from NWS Sioux Falls

In a toggle between Suomi NPP VIIRS Visible (0.64 µm) and “Snow/Ice” (1.61 µm) images at 1821 UTC (below),1.61 µm imagery showed the darker shades of flooding over a north/south portion of Interstate 29 that was closed from State Highway 34 (west of Glenwood, Iowa) to the Iowa/Missouri border (south of Hamburg, Iowa).

Suomi NPP VIIRS Near-Infrared "Vegetation" (0.86 µm) and "Snow/Ice" (1.61 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and “Snow/Ice” (1.61 µm) images; Interstate Highways are plotted in red, while State Highways are plotted in gray [click to enlarge]

Comparisons of Terra MODIS True Color and False Color Red-Green-Blue (RGB) images at 1720 UTC viewed using RealEarth are shown below. In the False color imagery, snow cover appears as lighter shades of cyan, while water appears as darker shades of blue.

Terra MODIS True Color and False Color RGB images [click to enlarge]

Terra MODIS True Color and False Color RGB images, centered over eastern Nebraska [click to enlarge]

Terra MODIS True Color and False Color RGB images, centered near Vermillion, South Dakota [click to enlarge]

Terra MODIS True Color and False Color RGB images, centered near Vermillion, South Dakota [click to enlarge]

Terra MODIS True Color and False Color RGB images, centered near Ames, Iowa [click to enlarge]

Terra MODIS True Color and False Color RGB images, centered near Ames, Iowa [click to enlarge]

===== 16 March Update =====

Landsat-8 False Color image. centered to the east of Sioux City, Iowa [click to enlarge]

Landsat-8 False Color image centered to the east of Sioux City, Iowa [click to enlarge]

An overpass of the Landsat-8 satellite at 1706 UTC on 16 March provided 30-meter resolution False Color imagery — 2 sections of the swath are shown above and below. The RealEarth link to interactively view the image is here.

Landsat-8 False Color image. centered to the south of Omaha, Nebraska [click to enlarge]

Landsat-8 False Color image centered to the south of Omaha, Nebraska [click to enlarge]

Closer views centered at the NWS Omaha forecast office — which had to be evacuated due to flooding — and just west of Offutt Air Force Base are shown below.

Landsat-8 False Color image. centered at the NWS forecast office in Valley, Nebraska [click to enlarge]

Landsat-8 False Color image centered at the NWS forecast office in Valley, Nebraska [click to enlarge]

Landsat-8 False Color image. centered near Offutt Air Force Base, Nebraska [click to enlarge]

Landsat-8 False Color image centered just west of Offutt Air Force Base, Nebraska [click to enlarge]

Cyclone Idai makes landfall in Mozambique

March 14th, 2019 |

Meteosat-8 Infrared (10.8 µm) and DMSP-17 SSMIS Microwave (85 GHz) images of Cyclone Idai at 1630 UTC [click to enlarge]

Meteosat-8 Infrared Window (10.8 µm) and DMSP-17 SSMIS Microwave (85 GHz) images of Cyclone Idai at 1630 UTC [click to enlarge]

Cyclone Idai — which had been slowly intensifying over warm water within the Mozambique Channel since 09 March — made landfall as a Category 2 storm along the coast of Mozambique on 14 March 2019. A toggle between Meteosat-8 Infrared Window (10.8 µm) and DMSP-17 SSMIS Microwave (85 GHz) images from the CIMSS Tropical Cyclones site (above) revealed a large and well-defined eye and eyewall structure at 1630 UTC. Idai had been rated at Category 3 intensity during 3 periods of time during its life cycle, most recently at 12 UTC on the day of landfall.

At 1911 UTC, Metop-A ASCAT winds in excess of 60  knots were sampled just west of the eyewall region (below).

Meteosat-8 Infrared Window (10.8 µm) image, with plots of Metop-A ASCAT winds at 1911 UTC [click to enlarge]

Meteosat-8 Infrared Window (10.8 µm) image, with plots of Metop-A ASCAT winds at 1911 UTC [click to enlarge]

A comparison of VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP, visualized using RealEarth, is shown below.

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

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

Idai had been moving through an environment of very low deep-layer wind shear — a favorable factor for maintaining its intensity — as shown in an animation of Meteosat-8 Infrared Window (10.8 µm) images (below).

Meteosat-8 Infrared Window (10.8 µm) images with contours of satellite-derived Deep-Layer Wind Shear valid at 18 UTC [click to enlarge]

Meteosat-8 Infrared Window (10.8 µm) images with contours of satellite-derived Deep-Layer Wind Shear valid at 18 UTC [click to enlarge]

The MIMIC TC product (below) suggested that Idai might have been in the early stage of an eyewall replacement cycle (ERC) just prior to making landfall. This, after completing a separate ERC during the preceding 48 hours.

MIMIC TC morphed microwave imagery [click to enlarge]

MIMIC TC morphed microwave image product [click to enlarge]

The eye of Idal was becoming cloud-filled as it approached the Mozambique coast, as seen on EUMETSAT Meteosat-8 High Resolution Visible (0.8 µm) images (below).

Meteosat-8 High Resolution Visible (0.8 µm) images [click to play animation]

Meteosat-8 High Resolution Visible (0.8 µm) images [click to play animation]

A time series of surface data from the port city of Beira FQBR (below) showed deteriorating conditions before observations ceased at 15 UTC.

Surface observation data from Beira, Mozambique [click to enlarge]

Surface observation data from Beira, Mozambique [click to enlarge]


Incidentally, an overpass of the Landsat-8 satellite on 11 March provided a 30-meter resolution view of the eye (below), soon after Idai’s first period of rapid intensification to Category 3 strength (SATCON). Surface mesovortices were apparent within the eye.

Landsat-8 False Color image of the eye of Idai on 11 March [click to play a zooming animation]

Landsat-8 False Color image of the eye of Idai on 11 March [click to play a zooming animation]