Satellite signatures of the Notre Dame Cathedral fire in Paris, France

April 15th, 2019 |

EUMETSAT Meteosat-11 Shortwave Infrared (3.92 µm) images, with airport identifiers plotted in red [click to play animation | MP4]

EUMETSAT Meteosat-11 Shortwave Infrared (3.92 µm) images, with airport identifiers plotted in red [click to play animation | MP4]

The subtle thermal anomaly (or “hot spot”) from the Notre Dame Cathedral Fire was evident in 4.8-km resolution (at satellite nadir) EUMETSAT Meteosat-11 Shortwave Infrared (3.92 µm) imagery (above) as a cluster of brighter yellow pixels just north of Paris Orly International Airport (LFPO) near the center of the images on 15 April 2019.

The fire reportedly began around 1650 UTC; the maximum 3.92 µm brightness temperature sensed by Meteosat-11 was 284.5 K (11.35ºC) on the 1745 UTC image, not long after the fire had spread to the large spire of the cathedral (Meteosat-11 was actually scanning the Paris area at 1756 UTC, since the Meteosat Second Generation satellites scan each Full Disk from south to north). Clouds approaching from the west began to mask the fire signature at 1930 UTC.

Even though high clouds had begun to move overhead, a thermal signature (darker black pixel) could still be seen in 1-km resolution Metop-A and Metop-C Shortwave Infrared (3.75 µm) images at 2009 and 2048 UTC (below, courtesy of William Straka, CIMSS). The maximum 3.75 µm brightness temperature detected by Metop was 291.1 K (18.0ºC).

Metop-A and Metop-C Shortwave Infrared (3.74 µm) images at 2009 and 2048 UTC [click to enlarge]

Metop-A and Metop-C Shortwave Infrared (3.75 µm) images at 2009 and 2048 UTC [click to enlarge]

Tropical Storm Iba off the coast of Brazil

March 24th, 2019 |

GOES-16

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

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.3 µm) images (below) showed the formation of Tropical Storm Iba off the east coast of Brazil at 16 UTC on 24 March 2019 (surface analyses). Plots of GLM Groups revealed some intermittent lightning activity. Tropical cyclones in the South Atlantic basin are rare — the last was in 2010, and only one example (Catarina in March 2004) is known to have reached hurricane intensity.

GOES-16 "Clean" Infrared Window (10.3 µm) images [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play animation | MP4]

A toggle between NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) from RealEarth (below) showed Iba at 1610 UTC.

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images at 1610 UTC [click to enlarge]

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images at 1610 UTC [click to enlarge]

GOES-16 Infrared images with an overlay of deep-layer wind shear valid at 18 UTC from the CIMSS Tropical Cyclones site (below) revealed a very tight gradient of shear over Iba. However, the shear gradient began to relax somewhat by 21 UTC.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with an overlay of 18 UTC deep-layer wind shear [click to enlarge]

In a sequence of GOES-16 “Clean” Infrared Window (10.3 µm) and Infrared-Water Vapor (10.3-6.9µm) brightness temperature difference (BTD) images (below), the clusters of deep convection propagating southward — east of Iba’s center of circulation, denoted by “I” — exhibited large negative BTD values (darker shades of red) suggestive of significant cloud-top penetration into the lower stratosphere (reference).

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) and Infrared-Water Vapor (10.3-6.9µm) BTD images [click to enlarge]

GOES-16 Visible images with an overlay of 1138 UTC ASCAT surface scatterometer winds from the Metop-A satellite (below) showed speeds in the 40-49 knot range (yellow barbs).

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with Metop-A ASCAT winds at 1137 UTC [click to enlarge]

The MIMIC Total Precipitable Water product (below) showed that Iba was embedded within a plume of moisture that extended southeastward off the coast of Brazil.

MIMIC Total Precipitable Water product [click to play animation]

MIMIC Total Precipitable Water product [click to play animation]

Sea Surface Temperature values (below) were around 30ºC in the waters where Iba intensified.

Sea Surface Temperature analysis at 2230 UTC on 23 March [click to enlarge]

Sea Surface Temperature analysis at 2230 UTC on 23 March [click to enlarge]

===== 25 March Update =====

GOES-16

GOES-16 “Red” Visible (0.64 µm) with GLM Groups (left) and “Clean” Infrared Window (10.3 µm, right) images [click to play animation | MP4]

A comparison of GOES-16 Visible and Infrared images (above) showed that increasing deep-layer wind shear had exposed the low-level circulation center of Iba. However, GLM Groups plotted on the Visible images revealed an increasing amount of lightning activity associated with a convective burst that began to wrap around the southern edge of the storm center after 15 UTC — and a brief cloud-top infrared brightness temperature of -90ºC (yellow pixel embedded with darker purple shades) was seen at 1635 UTC.

A timely overpass of the Suomi NPP satellite at 1639 UTC provided 375-meter resolution VIIRS True Color RGB and Infrared Window (11.45 µm) images (below), which showed a large overshooting top that exhibited infrared brightness temperatures of -90ºC and colder (yellow), with a warmer ring of compensating subsidence immediately surrounding it. The coldest pixel had a brightness temperature of -103.7ºC — which is almost 1ºC colder than the -102.96ºC value noted over Australia in 2008.

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

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

The explosive growth of that convective burst was very apparent in a toggle between VIIRS Infrared images from NOAA-20 at 1549 UTC and Suomi NPP at 1639 UTC (below, courtesy of William Straka, CIMSS). Note that the images use a slightly different variant of the color enhancement. A comparison of VIIRS True Color and Infrared images from NOAA-20 and Suomi NPP viewed using RealEarth is available here.

VIIRS Infrared (11.45 µm) images from NOAA-20 at 1549 UTC and Suomi NPP at 1639 UTC [click to enlarge]

VIIRS Infrared (11.45 µm) images from NOAA-20 at 1549 UTC and Suomi NPP at 1639 UTC [click to enlarge]

Tehuano wind event

March 5th, 2019 |

GOES-17 (left) and GOES-16 (right)

GOES-17 (left) and GOES-16 (right) “Red” Visible (0.64 µm) images, with plots of surface wind barbs (speed in knots) [click to play animation | MP4]

After a strong arctic cold front plunged southward across the US, the Gulf of Mexico, and then southern Mexico during the previous two days (surface analyses), GOES-17 (GOES-West) and GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) revealed the hazy plume of dust-laden Tehuano gap wind flow as it emerged from the southern coast of Mexico and spread southwestward across the Gulf of Tehuantepec and the Pacific Ocean on 05 March 2019. An image of the topography of southeastern Mexico shows the location of Chivela Pass, through which these gap winds flow. Along the Gulf of Mexico coast, surface winds gusted to 30 knots and higher after the cold front moved through Minatitlán/Coatzacoalcos International Airport (station identifier MMMT); off the Pacific coast, a ship in the Gulf of Tehuantepec reported a sustained wind speed of 30 knots at 12 UTC.

The GOES-16 Aerosol Optical Depth product (below) showed lightly enhanced AOD values toward the outer edges of the swath of Tehuano winds. Note the gap in the product during the afternoon hours, when large amounts of sun glint were present.

GOES-16 Aerosol Optical Depth product [click to play animation | MP4]

GOES-16 Aerosol Optical Depth product [click to play animation | MP4]

The GOES-16 Dust Detection product (below) did portray Low to Medium-Confidence areas of dust within the gap wind flow.

GOES-16 Dust Detection product [click to play animation | MP4]

GOES-16 Dust Detection product [click to play animation | MP4]

An overpass of the Suomi NPP satellite after 19 UTC provided numerous NUCAPS sounding profiles both within and outside of the perimeter of the Tehuano winds (below).

GOES-16 Aerosol Optical Depth product, with plots of available NUCAPS sounding profiles [click to enlarge]

GOES-16 Aerosol Optical Depth product, with plots of available NUCAPS sounding profiles [click to enlarge]

A comparison between a dry NUCAPS sounding (Point D) where the gap winds were first exiting the coast over the Gulf of Tehuantepec and a more “undisturbed” moist sounding (Point M) northwest of the gap wind flow is shown below. The dry air of the Tehuano wind flow was very shallow, but its presence could be seen in differences between the marine boundary layer dew point profile and the resulting height of the Lifting Condensation Level (LCL).

Comparison of Dry (D) and Moist (M) NUCAPS soundings [click to enlarge]

Comparison of Dry (D) and Moist (M) NUCAPS soundings [click to enlarge]

A NOAA-20 VIIRS True Color Red-Green-Blue (RGB) image viewed using RealEarth (below) also showed the hazy signature of dust-laden air.

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) image [click to enlarge]

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) image [click to enlarge]

===== 06 March Update =====

GOES-16 Shortwave Infrared (3.9 µm) image, with Metop-A ASCAT winds [click to enlarge]

GOES-16 Shortwave Infrared (3.9 µm) image, with Metop-A ASCAT winds [click to enlarge]

GOES-16 Shortwave Infrared (3.9 µm) images with overlays of Metop-A ASCAT winds around 0338 UTC (above) and 1607 UTC (below) revealed a secondary surge of Tehuano winds on 06 March. The highest wind speed at 0338 UTC was 44 knots, with 38 knots being measured at 1607 UTC.

GOES-16 Shortwave Infrared (3.9 µm) image, with Metop-A ASCAT winds [click to enlarge]

GOES-16 Shortwave Infrared (3.9 µm) image, with Metop-A ASCAT winds [click to enlarge]

GOES-16 Shortwave Infrared images (below) were useful to monitor the spread of cooler water (shades of yellow) as the strong surface winds induced upwelling — especially since the resulting strong gradient in water temperatures was falsely interpreted as cloud by the GOES-16 Sea Surface Temperature product.

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-17 and GOES-16 Visible images (below) showed how the swath of Tehuano winds had spread out toward the south and southwest compared to the previous day.

GOES-17 (left) and GOES-16 (right) "Red" Visible (0.64 µm) images, with plots of surface wind barbs (speed in knots) [click to play animation | MP4]

GOES-17 (left) and GOES-16 (right) “Red” Visible (0.64 µm) images, with plots of surface wind barbs (speed in knots) [click to play animation | MP4]

In contrast to the previous day, the GOES-16 Dust Detection product (below) showed a larger coverage of dust on 06 March — with significantly more Medium Confidence areas.

GOES-16 "Red" Visible (0.64 µm) images + Dust Detection product [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images + Dust Detection product [click to play animation | MP4]

A Suomi NPP VIIRS True Color RGB image at 1930 UTC (below) showed the hazy corridor of Tehuano winds bracketed by rope clouds.

Suomi NPP VIIRS True Color RGB image [click to enlarge]

Suomi NPP VIIRS True Color RGB image [click to enlarge]

Hurricane Force low in the West Pacific

January 10th, 2019 |
GOES-17

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

* GOES-17 images shown here are preliminary and non-operational *

GOES-17 “Red” Visible (0.64 µm) images (above) revealed the low-level circulation of an occluded Hurricane Force low (surface analyses) over the West Pacific Ocean on 09 January – 10 January 2019. This storm was forecast to produce wave heights up to 40-60 feet.

GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (below) showed the circulation of the storm at higher altitudes.

GOES-17 Low-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images [click to play animation | MP4]

GOES-17 Low-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images [click to play animation | MP4]

Metop-A ASCAT surface scatterometer wind speeds were as high as 67 knots southwest of the storm center and 63 knots to the northeast (below).

GOES-17 Mid-level Water Vapor (6.9 µm) image with Metop-A ASCAT surface scatterometer winds [click to enlarge]

GOES-17 Mid-level Water Vapor (6.9 µm) image with Metop-A ASCAT surface scatterometer winds [click to enlarge]

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

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

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