Rapid-scan (2.5-minute interval) Himawari-8 “Clean” Infrared Window (10.4 µm) images (above) showed the formation of a well-defined eye as Typhoon Yutu rapidly intensified from a Category 2 to a Category 4 storm  (ADT | SATCON) east of Guam on 23 October 2018. Cloud-top infrared brightness temperatures were -90ºC or colder (yellow pixels embedded within violet-enhanced areas) — which was several degrees colder than the -84ºC tropopause temperature on rawinsonde data at Guam (below).

During this period of rapid intensification, Yutu was moving over very warm water and through an environment of low (favorable) deep-layer wind shear — and satellite-derived winds from the CIMSS Tropical Cyclones site (below) showed the development of well-defined mid/upper-level outflow channels to the northwest and southeast of the storm, which also aided the intensification process.

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GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images (above) showed Willa during the 48 hours that it rapidly intensified (ADT | SATCON) from a Tropical Storm at 15 UTC on 20 October to a Category 5 Hurricane at 15 UTC on 22 October 2018. Willa  — which became the third Category 5 hurricane of the 2018 season in the northeast Pacific basin (east of 180º longitude) — formed and had been moving over very warm water, with Sea Surface Temperatures of 29-30ºC. Deep-layer wind shear was also light during the 15 hour period lead up to Category 5 intensity.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (below; courtesy of William Straka, CIMSS) showed Category 4 Willa off the west coast of Mexico at 0852 UTC on 22 October. The Moon was in the Waxing Gibbous phase (at 95% of Full), providing ample illumination for a “visible image at night” using the VIIRS Day/Night Band. Intricate cloud-top gravity waves were seen propagating radially outward from the storm center.

1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window images (below) revealed the small eye of the Category 5 hurricane after sunrise, with multiple convective bursts that erupted along the western edge of the eyewall. A continuous series of storm-top waves could be seen propagating radially outward away from the eye on Visible imagery. However, the eye eventually became cloud-filled as Willa began to undergo an eyewall replacement cycle — the formation of a larger-diameter outer eyewall was evident on the MIMIC-TC product — and weaken to a Category 4 intensity.

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

GOES-17 “Red” Visible (0.64 µm) images (below) provided a more direct view of the storm, since the satellite was positioned over the Equator at 89.5º W longitude while in its post-launch testing location.

October 23 is the last full day, for a while, to use GOES-16 and GOES-17 data to produce stereoscopic imagery. GOES-17 is set to cease data transmission on 24 October around 1500 UTC as it starts its motion towards its operational GOES-West position of 137.2º W Longitude. The animation below, starting at 1307 UTC on 23 October, (click here for an animated gif) shows the occasional appearance of an eye within the storm center on 23 October as it approached the coast. To view the image in three dimensions, cross your eyes until 3 images are apparent, then focus on the image in the middle.

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Thanks go out to Jason Alumbaugh from NWS Marquette, who sent the following in an email:

“Previous shift here at NWS Marquette passed along interesting feature on satellite last night. Origin of the feature is approx. 49.23 N and 91.00 W (just west of CWDV – Upsala in Ontario) but eventually the plume spread as far south as south central Upper Michigan and northeast Wisconsin (IMT to MNM). Our meteorologists said it looked like a fire and called Environment Canada overnight but they had not heard of anything reported.”

Taking a look at the initial daytime formation of the plume on 20 October 2018, a very subtle signature could be seen at times in GOES-16 (GOES-East) “Red” Visible (0.64 µm) images, but the plume was more obvious in the Near-Infrared “Snow/Ice” (1.61 µm), Near-Infrared “Cloud Particle Size” (2.24 µm) and Shortwave Infrared (3.9 µm) imagery (above). Emissions from an industrial source (likely a power plant, or perhaps the Domtar paper mill?) acted as cloud condensation nuclei, causing a higher concentration of smaller supercooled cloud droplets downwind of the plume source — and this plume of smaller particles was more reflective and thus appeared brighter in the 1.61/2.24 µm images and warmer (darker gray) in the 3.9 µm images.

Color-enhanced 3.9 µm Shortwave Infrared imagery (below) showed the transition from a warmer (darker red) plume during the day — due to enhanced reflection of incoming solar radiation — to a colder (darker blue) plume at night.

The higher spatial resolution of MODIS and VIIRS imagery from the polar-orbiting Terra/Aqua and NOAA-20/Suomi NPP satellites offered alternative views of the plume. A comparison of Suomi NPP VIIRS Visible (0.64 µm), Day/Night Band (0.7 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images (below) showed the early stage of the plume during the day on 20 October — as was seen with GOES-16, the plume signature was most obvious in the 1.61 µm Snow/Ice and 3.74 µm Shortwave Infrared imagery.

A nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.74 µm), Infrared Window (11.45 µm) and Fog/stratus Brightness Temperature Difference (11.45-3.74 µm) images (below) revealed signatures of the plume at 0716 UTC or 2:16 am CDT on 21 October, after it had traveled nearly 350 miles from the Ontario source to the Green Bay, Wisconsin area. Cloud-top 11.45 µm infrared brightness temperatures of the plume and the surrounding supercooled clouds were generally in the -13º to -16ºC range.

A sequence of nighttime Fog/stratus BTD images from Terra/Aqua MODIS and NOAA-20/Suomi NPP VIIRS (below) showed the plume moving southeastward across the Upper Peninsula of Michigan into northeastern Wisconsin. BTD values associated with the plume were in the 3-5ºC range (darker shades of red). [Note: the NOAA-20 VIIRS images are incorrectly labeled as Suomi NPP]

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Aerolineas Argentinas Flight 1303 encountered severe turbulence while flying from Miami, Florida to Buenos Aires, Argentina on 18 October 2018 (media report). The flight track (above) and flight log data indicated that the aircraft rapidly gained then lost over 2000 feet in altitude around 1823 UTC while over far western Brazil.

GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images (below) showed a cluster of rapidly-developing thunderstorms at that location and time (within the red circle) — cloud-top infrared brightness temperatures were colder than -80ºC (shades of violet).

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