Hurricane Cristobal and the Saharan Air Layer

August 28th, 2014
Meteosat-10 Saharan Air Layer product (click to play animation)

Meteosat-10 Saharan Air Layer product (click to play animation)

The CIMSS Saharan Air Layer (SAL) product (above; click image to play animation) showed a large pocket of SAL (yellow to red color enhancement) drifting westward over the far western Atlantic Ocean and toward the Gulf of Mexico on 28 August 2014.

On GOES-13 0.63 µm visible channel images (below; click image to play animation), the hazy signature of the SAL dust could be seen surging westward, not far to the south of Category 1 intensity Hurricane Cristobal.

GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

The SAL also exhibited a warm/dry signature (yellow to orange color enhancement) on the corresponding GOES-13 6.5 µm water vapor channel images (below; click image to play animation).

GOES-13 6.5 µm water vapor channel images (click to play animation)

GOES-13 6.5 µm water vapor channel images (click to play animation)

At 17:16 UTC, a Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image from the SSEC RealEarth web map server (below) showed that Hurricane Cristobal had developed an eye formation.

Suomi NPP VIIRS true-color image

Suomi NPP VIIRS true-color image

A comparison of AWIPS-2 images of Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel data (below) revealed that the coldest cloud-top IR brightness temperatures (-77º C, lighter gray color enhancement) were located within convection just southwest and southeast of the eye.

Suomi NPP VIIRS 0.64 µm visible image and 11.45 µm IR channel image

Suomi NPP VIIRS 0.64 µm visible image and 11.45 µm IR channel image

Air Algerie Plane Crash in Mali

July 24th, 2014
Meteosat-10 10.8 µm infrared channel images (click to enlarge)

Meteosat-10 10.8 µm infrared channel images (click to enlarge)

An Air Algerie Flight AH5017 crashed less than an hour after taking off from Ouagadougou, Burkina Faso (the southern asterisk in the animation above). Contact was lost at 0155 UTC (Press Report) and wreckage was found southeast of the Gossi, Mali (the northern asterisk in the animation above). Cloud-top IR Brightness Temperatures in the Mesoscale Convective System through which the plane flew were as cold as -78º C.

Suomi NPP was flying over Mali and Burkina Faso at 0152 UTC on 24 July and provided high-resolution infrared and Day/Night Band imagery along the flight path. The toggle below, of the VIIRS 11.45 µm infrared and 0.70 µm Day/Night Band (Imagery courtesy of William Straka, UW CIMSS) shows the convective storm. The bright lights of Ouagadougou are evident, as well as lightning streaks within the storm. (Click for zoomed-in versions of 11.45 µm and Day Night Band images)

Suomi NPP VIIRS 11.45 µm infrared and 0.7 µm Day/Night Band images (click to enlarge)

Suomi NPP VIIRS 11.45 µm infrared and 0.7 µm Day/Night Band images (click to enlarge)

============================= Added 28 July 2014 =========================

Suomi NPP VIIRS 0.7 µm Day/Night Band image (click to enlarge)

Suomi NPP VIIRS 0.7 µm Day/Night Band image (click to enlarge)

The image above includes the light flare from the actual plane crash, circled in red. Suomi NPP was passing over the crash site between 1:55:00 and 1:55:30 UTC on 24 July 2014 (Link, navigation computed from Two Line Element files). The animation below shows Day/Night Band imagery (also courtesy of William Straka, UW CIMSS) from before the crash (21 July), the time of the crash on the 24th, and after the crash (25 July).

Suomi NPP VIIRS 0.7 µm Day/Night Band imagery on three days in July (click to Animate)

Suomi NPP VIIRS 0.7 µm Day/Night Band imagery on three days in July (click to Animate)

Saharan Air Layer dust over the Gulf of Mexico

June 21st, 2014
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

McIDAS images of GOES-13 0.63 µm visible channel data on 20 June 2014 (above; click image to play animation; also available as an MP4 movie file) and on 21 June 2014 (below; click image to play animation; also available as an MP4 animation file) revealed the hazy signature of a veil of Saharan Air Layer (SAL) dust aloft over much of the southern and western portions of the Gulf of Mexico.

GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

The hazy dust signature also showed up well in Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images, as visualized using the SSEC RealEarth web map server (below).

Suomi NPP VIIRS true-color RGB images

Suomi NPP VIIRS true-color RGB images

The SAL tracking product showed the strong pulse of SAL dust emerging from the African continent on 10 June, then moving rapidly westward across the Atlantic Ocean and over the Caribbean Sea by 17 June (below; click image to play animation).

Meteosat-10 Saharan Air Layer tracking product (click to play animation)

Meteosat-10 Saharan Air Layer tracking product (click to play animation)

Thunderstorms producing very large hail near Paris, France

June 9th, 2014
Meteosat-10 0.7 µm visible channel images (click to play animation)

Meteosat-10 0.7 µm visible channel images (click to play animation)

Severe thunderstorms developed over parts of France on 09 June 2014, some of which produced very large hail (photos). EUMETSAT Meteosat-10 1-km resolution 0.7 µm visible channel images (above; click image to play animation; also available as an MP4 movie file) and 3-km resolution 10.8 µm IR channel images (below; click image to play animation; also available as an MP4 movie file) revealed some interesting details in the thunderstorm structure: a narrow flanking line was seen on the visible imagery, and the storms exhibited well-defined “enhanced-V” signatures and thermal couplets on the IR imagery. For reference, the asterisk marks the location of the Charles De Gaulle Airport in Paris.

Meteosat-10 10.8 µm IR channel images (click to play animation)

Meteosat-10 10.8 µm IR channel images (click to play animation)

The Suomi NPP satellite overpass of the region occurred around 12:15 UTC, allowing the VIIRS instrument to provide a 375-meter resolution true-color Red/Green/Blue (RGB) image of the developing thunderstorms (below, visualized using the SSEC RealEarth web map server).

Suomi NPP VIIRS true-color RGB image

Suomi NPP VIIRS true-color RGB image